Abstract: In this study we investigated the molecular mechanism of glutathionylation on isolated human cardiac myofibrils using several pro-glutathionylating agents. Total glutathionylated proteins appeared significantly enhanced with all the pro-oxidants used. The increase was completely reversed by the addition of a reducing agent, demonstrating that glutathione binding occurs by a disulfide and that the process is reversible. A sensitive target of glutathionylation was alpha-actin, showing a different reactivity to the several pro-glutathionylating agents by ELISA. Noteworthy, myosin although highly sensitive to the in vitro glutathionylation does not represent the primary glutathionylation target in isolated myofibrils. Light scattering measurements of the glutathionylated alpha-actin showed a slower polymerisation compared to the non-glutathionylated protein and force development was depressed after glutathionylation, when the myofibrils were mounted in a force recording apparatus. Interestingly, confocal laser scanning microscopy of cardiac cryosections indicated, for the first time, the constitutive glutathionylation of alpha-cardiac actin in human heart. Due to the critical location of alpha-actin in the contractile machinery and to its susceptibility to the oxidative modifications, glutathionylation may represent a mechanism for modulating sarcomere assembly and muscle functionality under patho-physiological conditions in vivo.
Abstract: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by homozygous mutations of the SMN1 gene. Three forms of SMA are recognized (type I-III) on the basis of clinical severity. All patients have at least one or more (usually 2-4) copies of a highly homologous gene (SMN2), which produces insufficient levels of functional SMN protein, because of alternative splicing of exon 7. Recently, evidence has been provided that SMN2 expression can be enhanced by pharmacological treatment. However, no reliable biomarkers are available to test the molecular efficacy of the treatments. At present, the only potential biomarker is the dosage of SMN products in peripheral blood. However, the demonstration that SMN full-length (SMN-fl) transcript levels are reduced in leukocytes of patients compared with controls remains elusive (except for type I). We have developed a novel assay based on absolute real-time PCR, which allows the quantification of SMN1-fl/SMN2-fl transcripts. For the first time, we have shown that SMN-fl levels are reduced in leukocytes of type II-III patients compared with controls. We also found that transcript levels are related to clinical severity as in type III patients SMN2-fl levels are significantly higher compared with type II and directly correlated with functional ability in type II patients and with age of onset in type III patients. Moreover, in haploidentical siblings with discordant phenotype, the less severely affected individuals showed significantly higher transcript levels. Our study shows that SMN2-fl dosage in leukocytes can be considered a reliable biomarker and can provide the rationale for SMN dosage in clinical trials.
Abstract: Rebuilding brain structure and neural circuitries by transplantation of fetal tissue is a strategy to repair the damaged nervous system and is currently being investigated using striatal primordium in Huntington's disease (HD) patients. Four HD patients underwent bilateral transplantation with human fetal striatal tissues (9-12 week gestation). Small blocks of whole ganglionic eminencies were processed to obtain cell suspension and then stereotactically grafted in the caudate head and in the putamen. Follow-up period ranged between 18 and 34 months (mean, 24.7 months). Surgery was uneventful. Starting from the fourth month after grafting, neo-generation of metabolically active tissue with striatal-like MRI features was observed in 6 out of 8 grafts. The increase in D2 receptor binding suggested striatal differentiation of the neo-generated tissue in 3 patients. New tissue, connecting the developing grafts with the frontal cortex and, in one case, with the ventral striatum, was also observed. The new tissue growth halted after the ninth month post transplantation. All patients showed stabilization or improvement in some neurological indices. No clinical and imaging signs, suggestive of graft uncontrolled growth, were seen. This study provides the first evidence in humans that neuroblasts of a striatal primordium can develop and move into the brain after neurotransplantation. Primordium development resulted in the building of a new structure with the same imaging features as the corresponding mature structure, combined with short- and long-distance targeted migration of neuroblasts. The results of this study support both the reconstructive potential of fetal tissue and the remarkably retained plasticity of adult brain. Further studies are necessary to assess the clinical efficacy of the human fetal striatal transplantation.
Abstract: The motor skills of patients with spinal muscular atrophy, type I (SMA-I) are very limited. It is difficult to quantify the motor abilities of these patients and as a result there is currently no validated measure of motor function that can be utilized as an outcome measure in clinical trials of SMA-I. We have developed the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders ("CHOP INTEND") to evaluate the motor skills of patients with SMA-I. The test was developed following the evaluation of 26 infants with SMA-I mean age 11.5months (1.4-37.9months) with the Test of Infant Motor Performance and The Children's Hospital of Philadelphia Test of Strength in SMA, a newly devised motor assessment for SMA. Items for the CHOP INTEND were selected by an expert panel based on item mean and standard deviation, item frequency distribution, and Chronbach's alpha. Intra-rater reliability of the resulting test was established by test-retest of 9 infants with SMA-I over a 2month period; Intraclass correlation coefficient (ICC) (3,1)=0.96. Interrater reliability was by video analysis of a mixed group of infants with neuromuscular disease by 4 evaluators; ICC (3,4)=0.98 and in a group of 8 typically developing infants by 5 evaluators ICC (3,5)=0.93. The face validity of the CHOP INTEND is supported by the use of an expert panel in item selection; however, further validation is needed. The CHOP INTEND is a reliable measure of motor skills in patients with SMA-I and neuromuscular disorders presenting in infancy.
Abstract: Limb-girdle muscular dystrophies (LGMDs) are a genetically heterogeneous group of neuromuscular disorders with a selective or predominant involvement of shoulder and pelvic girdles. We clinically examined 19 members in a four-generation Italian family with autosomal-dominant LGMD. A total of 11 subjects were affected. Clinical findings showed variable expressivity in terms of age at onset and disease severity. Five subjects presented with a slowly progressive proximal muscle weakness, in both upper and lower limbs, with onset during the fourth-fifth decade of life, which fulfilled the consensus diagnostic criteria for LGMD. Earlier onset of the disease was observed in a group of patients presenting with muscle weakness and/or calf hypertrophy, and/or occasionally high CK and lactate serum levels. Two muscle biopsies showed morphological findings compatible with MD associated with subsarcolemmal accumulation of mitochondria and the presence of multiple mitochondrial DNA deletions. A genome-wide scan performed using microsatellite markers mapped the disease on chromosome 3p23-p25.1 locus in a 25-cM region between markers D3S1263 and D3S3685. The highest two-point LOD score was 3.26 (theta=0) at marker D3S1286 and D3S3613, whereas non-parametric analysis reached a P-value=0.0004. Four candidate genes within the refined region were analysed but did not reveal any mutations. Our findings further expand the clinical and genetic heterogeneity of LGMDs.European Journal of Human Genetics advance online publication, 13 January 2010; doi:10.1038/ejhg.2009.235.
Abstract: Autosomal recessive spastic paraplegia with thinning of corpus callosum (ARHSP-TCC) is a complex form of HSP initially described in Japan but subsequently reported to have a worldwide distribution with a particular high frequency in multiple families from the Mediterranean basin. We recently showed that ARHSP-TCC is commonly associated with mutations in SPG11/KIAA1840 on chromosome 15q. We have now screened a collection of new patients mainly originating from Italy and Brazil, in order to further ascertain the spectrum of mutations in SPG11, enlarge the ethnic origin of SPG11 patients, determine the relative frequency at the level of single Countries (i.e., Italy), and establish whether there is one or more common mutation. In 25 index cases we identified 32 mutations; 22 are novel, including 9 nonsense, 3 small deletions, 4 insertions, 1 in/del, 1 small duplication, 1 missense, 2 splice-site, and for the first time a large genomic rearrangement. This brings the total number of SPG11 mutated patients in the SPATAX collection to 111 cases in 44 families and in 17 isolated cases, from 16 Countries, all assessed using homogeneous clinical criteria. While expanding the spectrum of mutations in SPG11, this larger series also corroborated the notion that even within apparently homogeneous population a molecular diagnosis cannot be achieved without full gene sequencing.
Abstract: Yap is a small protein that binds to many transcription factors and modulates their activity. Yap was described to increase the ability of p73 in inducing apoptosis as a consequence of damage to the DNA, and therefore its activity was thought to favor tumor-suppression. However, other studies have recently shown a role for Yap in cell differentiation, cell transformation and in the regulation of organ size. It has been demonstrated that the Drosophila Hippo pathway has a mammalian equivalent, and that Yap is part of this pathway, where it might stimulate proliferation. In light of these new findings we ought to re-consider the role of Yap, which seems to be in service of several masters, and whose regulation--likely at the level of PTM--and cellular context might have a pivotal role in the choice of its partners and consequently on the final outcome.
Abstract: Menkes disease (MD) is a rare and severe X-linked recessive disorder of copper metabolism. The MD gene, ATP7A (ATPase Cu++ transporting alpha polypeptide), encodes an ATP-dependent copper-binding membrane protein. In this report, we describe a girl with typical clinical features of MD, carrying a balanced translocation between the chromosomes X and 16 producing the disruption of one copy of ATP7A gene and the silencing of the other copy because of the chromosome X inactivation. Fluorescence in situ hybridization experiments with bacterial derived artificial chromosome probes revealed that the breakpoints were located within Xq13.3 and 16p11.2. Replication pattern analysis demonstrated that the normal X chromosome was late replicating and consequently inactivated, whereas the der(X)t(X;16), bearing the disrupted ATP7A gene, was active. An innovative approach, based on FMR1 (fragile X mental retardation 1) gene polymorphism, has been used to disclose the paternal origin of the rearrangement providing a new diagnostic tool for determining the parental origin of defects involving the X chromosome and clarifying the mechanism leading to the cytogenetic rearrangement that occurred in our patient.
Abstract: The neuronal ceroid lipofuscinoses (NCL) are a group of genetically heterogeneous neurodegenerative disorders. The recent identification of the MFSD8/CLN7 gene in a variant-late infantile form of NCL (v-LINCL) in affected children from Turkey prompted us to examine the relative frequency of variants in this gene in Italian patients with v-LINCL. We identified nine children harboring 11 different mutations in MFSD8/CLN7. Ten mutations were novel and included three nonsense (p.Arg35Stop, p.Glu381Stop, p.Arg482Stop), four missense (p.Met1Thr, p.Gly52Arg, p.Thr294Lys, p.Pro447Leu), two splice site mutations (c.863+3_4insT, c.863+1G>C), and a 17-bp deletion predicting a frameshift and premature protein truncation (c.627_643del17/p.Met209IlefsX3). The clinical phenotype, which was similar to that of the Turkish v-LINCL cases, was not influenced by type and location of the mutation nor the length of the predicted residual gene product. As well as identifying novel variants in MFSD8/CLN7, this study contributes to a better molecular characterization of Italian NCL cases, and will facilitate medical genetic counseling in such families. The existence of a subset of v-LINCL cases without mutations in any of the known NCL genes suggests further genetic heterogeneity.
Abstract: BACKGROUND: Periventricular heterotopia (PH) is an etiologically heterogeneous disorder characterized by nodules of neurons ectopically placed along the lateral ventricles. Most affected patients have seizures and their cognitive level varies from normal to severely impaired. At present, two genes have been identified to cause PH when mutated. Mutations in FLNA (Xq28) and ARFGEF2 (20q13) are responsible for X-linked bilateral PH and a rare autosomal recessive form of PH with microcephaly. Chromosomal rearrangements involving the 1p36, 5p15, and 7q11 regions have also been reported in association with PH but the genes implicated remain unknown. Fourteen additional distinct anatomoclinical PH syndromes have been described, but no genetic insights into their causes have been gleaned. METHODS: We report the clinical and imaging features of three unrelated patients with epilepsy, mental retardation, and bilateral PH in the walls of the temporal horns of the lateral ventricles, associated with a de novo deletion of the 5q14.3-15 region. We used microarray-based comparative genomic hybridization to define the boundaries of the deletions. RESULTS: The three patients shared a common deleted region spanning 5.8 Mb and containing 14 candidate genes. CONCLUSION: We identified a new syndrome featuring bilateral periventricular heterotopia (PH), mental retardation, and epilepsy, mapping to chromosome 5q14.3-q15. This observation reinforces the extreme clinical and genetic heterogeneity of PH. Array comparative genomic hybridization is a powerful diagnostic tool for characterizing causative chromosomal rearrangements of limited size, identifying potential candidate genes for, and improving genetic counseling in, malformations of cortical development.
Abstract: DMD gene exons duplications account for up to 5-10 % of Duchenne (DMD) and up to 5-19% of Becker (BMD) muscular dystrophies; as for the more common deletions, the genotype-phenotype correlation and the genetic prognosis are generally based on the "reading frame rule". Nevertheless, the transcriptional profile of duplications, abridging the genomic configuration to the eventual protein effect, has been poorly studied. We describe 26 DMD gene duplications occurring in 33 unrelated patients and detected among a cohort of 194 mutation-positive DMD/BMD patients. We have characterized at the RNA level 16 of them. Four duplications (15%) behave as exception to the reading frame rule. In three BMD cases with out-of-frame mutations, the RNA analysis revealed that exon skipping events occurring in the duplicated region represent the mechanism leading to the frame re-establishment and to the milder phenotype. Differently, in a DMD patient carrying an in-frame duplication the RNA behaviour failed to explain the clinical phenotype which is probably related to post-transcriptional-translational mechanisms. We conclude that defining the RNA profile in DMD gene duplications is mandatory both for establishing the genetic prognosis and for approaching therapeutic trials based on hnRNA modulation.
Abstract: The acronym COACH defines an autosomal recessive condition of Cerebellar vermis hypo/aplasia, Oligophrenia, congenital Ataxia, Coloboma and Hepatic fibrosis. Patients present the "molar tooth sign", a midbrain-hindbrain malformation pathognomonic for Joubert Syndrome (JS) and Related Disorders (JSRDs). The main feature of COACH is congenital hepatic fibrosis (CHF), resulting from malformation of the embryonic ductal plate. CHF is invariably found also in Meckel syndrome (MS), a lethal ciliopathy already found to be allelic with JSRDs at the CEP290 and RPGRIP1L genes. Recently, mutations in the MKS3 gene (approved symbol TMEM67), causative of about 7% MS cases, have been detected in few Meckel-like and pure JS patients. Analysis of MKS3 in 14 COACH families identified mutations in 8 (57%). Features such as colobomas and nephronophthisis were found only in a subset of mutated cases. These data confirm COACH as a distinct JSRD subgroup with core features of JS plus CHF, which major gene is MKS3, and further strengthen gene-phenotype correlates in JSRDs.
Abstract: BACKGROUND: Congenital muscular dystrophies (CMD) with reduced glycosylation of alpha-dystroglycan (alpha-DG) are a heterogeneous group of conditions associated with mutations in six genes encoding proven or putative glycosyltransferases. OBJECTIVES: The aim of the study was to establish the prevalence of mutations in the six genes in the Italian population and the spectrum of clinical and brain MRI findings. METHODS: As part of a multicentric study involving all the tertiary neuromuscular centers in Italy, FKRP, POMT1, POMT2, POMGnT1, fukutin, and LARGE were screened in 81 patients with CMD and alpha-DG reduction on muscle biopsy (n = 76) or with a phenotype suggestive of alpha-dystroglycanopathy but in whom a muscle biopsy was not available for alpha-DG immunostaining (n = 5). RESULTS: Homozygous and compound heterozygous mutations were detected in a total of 43/81 patients (53%), and included seven novel variants. Mutations in POMT1 were the most prevalent in our cohort (21%), followed by POMT2 (11%), POMGnT1 (10%), and FKRP (9%). One patient carried two heterozygous mutations in fukutin and one case harbored a new homozygous variant in LARGE. No clear-cut genotype-phenotype correlation could be observed with each gene, resulting in a wide spectrum of clinical phenotypes. The more severe phenotypes, however, appeared to be consistently associated with mutations predicted to result in a severe disruption of the respective genes. CONCLUSIONS: Our data broaden the clinical spectrum associated with mutations in glycosyltransferases and provide data on their prevalence in the Italian population.
Abstract: Systemic lupus erythematosus (SLE) is an autoimmune disease mediated by autoantibodies and preferentially affecting women of childbearing age. Because the offspring of mothers with SLE show a high frequency of learning disorders, we hypothesized that maternally transferred autoantibodies that bind DNA and the N-methyl-D-aspartate receptor (NMDAR) could have a pathogenic role during fetal brain development. Here we describe a maternal SLE mouse model wherein pregnant dams harbored DNA-specific, NMDAR-specific autoantibodies throughout gestation. High titers of these autoantibodies in maternal circulation led to histological abnormalities in fetal brain and subsequent cognitive impairments in adult offspring. These data support a paradigm in which in utero exposure to neurotoxic autoantibodies causes abnormal brain development with long-term consequences. This paradigm may apply to multiple congenital neuropsychiatric disorders.
Abstract: This paper covers genetic and biochemical aspects of mitochondrial bioenergetics dysfunction in hereditary neurological disorders associated with complex I defects. Three types of hereditary complex I dysfunction are dealt with: (i) homozygous mutations in the nuclear genes NDUFS1 and NDUFS4 of complex I, associated with mitochondrial encephalopathy; (ii) a recessive hereditary epileptic neurological disorder associated with enhanced proteolytic degradation of complex I; (iii) homoplasmic mutations in the ND5 and ND6 mitochondrial genes of the complex, coexistent with mutation in the nuclear PINK1 gene in familial Parkinsonism. The genetic and biochemical data examined highlight different mechanisms by which mitochondrial bioenergetics is altered in these hereditary defects of complex I. This knowledge, besides clarifying molecular aspects of the pathogenesis of hereditary diseases, can also provide hints for understanding the involvement of complex I in sporadic neurological disorders and aging, as well as for developing therapeutical strategies.
Abstract: Friedreich's ataxia (FRDA) is an autosomal recessive disorder caused by mutations in the gene encoding frataxin, a mitochondrial protein implicated in iron metabolism. Current evidence suggests that loss of frataxin causes iron overload in tissues, and increase in free-radical production leading to oxidation and inactivation of mitochondrial respiratory chain enzymes, particularly Complexes I, II, III and aconitase. Glutathione plays an important role in the detoxification of ROS in the Central Nervous System (CNS), where it also provides regulation of protein function by glutathionylation. The cytoskeletal proteins are particularly susceptible to oxidation and appear constitutively glutathionylated in the human CNS. Previously, we showed loss of cytoskeletal organization in fibroblasts of patients with FRDA found to be associated with increased levels of glutathione bound to cytoskeletal proteins. In this study, we analysed the glutathionylation of proteins in the spinal cord of patients with FRDA and the distribution of tubulin and neurofilaments in the same area. We found, for the first time, a significant rise of the dynamic pool of tubulin as well as abnormal distribution of the phosphorylated forms of human neurofilaments in FRDA motor neurons. In the same cells, the cytoskeletal abnormalities co-localized with an increase in protein glutathionylation and the mitochondrial proteins were normally expressed by immunocytochemistry. Our results suggest that in FRDA oxidative stress causes abnormally increased protein glutathionylation leading to prominent abnormalities of the neuronal cytoskeleton.
Abstract: Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.
Abstract: Splicing mutations occurring outside the invariant GT and AG dinucleotides are frequent in disease genes and the definition of their pathogenic potential is often challenging. We have identified four patients affected by Ullrich congenital muscular dystrophy and carrying unusual mutations of COL6 genes affecting RNA splicing. In three cases the mutations occurred in the COL6A2 gene and consisted of nucleotide substitutions within the degenerated sequences flanking the canonical dinucleotides. In the fourth case, a genomic deletion occurred which removed the exon8-intron8 junction of the COL6A1 gene. These mutations induced variable splicing phenotypes, consisting of exon skipping, intron retention and cryptic splice site activation/usage. A quantitative RNA assay revealed a reduced level of transcription of the mutated in-frame mRNA originating from a COL6A2 point mutation at intronic position +3. At variance, the transcription level of the mutated in-frame mRNA originating from a genomic deletion which removed the splicing sequences of COL6A1 exon 8 was normal. These findings suggest a different transcriptional efficiency of a regulatory splicing mutation compared to a genomic deletion causing a splicing defect.
Abstract: Phosphotidylinositol (PtdIns) signaling is tightly regulated both spatially and temporally by subcellularly localized PtdIns kinases and phosphatases that dynamically alter downstream signaling events. Joubert syndrome is characterized by a specific midbrain-hindbrain malformation ('molar tooth sign'), variably associated retinal dystrophy, nephronophthisis, liver fibrosis and polydactyly and is included in the newly emerging group of 'ciliopathies'. In individuals with Joubert disease genetically linked to JBTS1, we identified mutations in the INPP5E gene, encoding inositol polyphosphate-5-phosphatase E, which hydrolyzes the 5-phosphate of PtdIns(3,4,5)P3 and PtdIns(4,5)P2. Mutations clustered in the phosphatase domain and impaired 5-phosphatase activity, resulting in altered cellular PtdIns ratios. INPP5E localized to cilia in major organs affected by Joubert syndrome, and mutations promoted premature destabilization of cilia in response to stimulation. These data link PtdIns signaling to the primary cilium, a cellular structure that is becoming increasingly recognized for its role in mediating cell signals and neuronal function.
Abstract: The aim of this study was to investigate the suitability of the North Star Ambulatory Assessment as a possible outcome measure in multicentric clinical trials. More specifically we wished to investigate the level of training needed for achieving a good interobserver reliability in a multicentric setting. The scale was specifically designed for ambulant children with Duchenne Muscular Dystrophy and includes 17 items that are relevant for this cohort. Thirteen Italian centers participated in the study. In the first phase of the study we provided two training videos and an example of the scale performed on a child. After the first session of training, all the 13 examiners were asked to send a video with an assessment performed in their centre and to score all the videos collected. There were no difficulties in performing the items and in obtaining adequate videos with a hand held camera but the results showed a poor interobserver reliability (<.5). After a second training session with review and discussion of the videos previously scored, the same examiners were asked to score three new videos. The results of this session had an excellent interobserver reliability (.995). The level of agreement was maintained even when the same videos were rescored after a month, showing a significant intra-observer reliability (.95). Our results suggest that the NSAA is a test that can be easily performed, completed in 10 min and can be used in a multicentric setting, providing that adequate training is administered.
Abstract: A brief and comprehensive review on mitochondrial cytopathies is reported showing the extreme clinical and genetic heterogeneity of these disorders. Syndromes of mitochondrial cytopathiesencompass most of the medical specialties and diagnosis of mitochondrial cytopathies is complicated,needing the combination of multiple expertise: muscle morphology, neuroradiology, biochemistry(enzymology, chemical analysis), and genetics.
Abstract: Mitochondrial ATP synthase plays a central role in cell function by synthesising most of the ATP in human tissues. In different cells, active regulation of mitochondrial ATP synthase in response to cellular energy demand has been demonstrated, as well as its alteration under several pathological conditions affecting oxidative phosphorylation (OXPHOS). Traditionally, detection of OXPHOS defects is based on the spectrophotometric measurement of respiratory chain complex activities in muscle biopsies. Considering the broad clinical spectrum of mitochondrial disorders, and the difficulty in arriving at a single diagnostic method, in this study we propose measurement of ATP synthesis in mitochondria from skin fibroblasts as an effective screening tool. In the light of our results this assessment emerges as a useful marker of impaired energy production in primary OXPHOS disorders of childhood and as a tool with the potential to drive further molecular genetic studies.
Abstract: Aicardi-Goutières syndrome is a mendelian mimic of congenital infection and also shows overlap with systemic lupus erythematosus at both a clinical and biochemical level. The recent identification of mutations in TREX1 and genes encoding the RNASEH2 complex and studies of the function of TREX1 in DNA metabolism have defined a previously unknown mechanism for the initiation of autoimmunity by interferon-stimulatory nucleic acid. Here we describe mutations in SAMHD1 as the cause of AGS at the AGS5 locus and present data to show that SAMHD1 may act as a negative regulator of the cell-intrinsic antiviral response.
Abstract: Pelizaeus-Merzbacher disease (PMD) is an X-linked myelination disorder most frequently caused by duplication of a genomic segment of variable length containing the PLP1 gene. We studied five PMD male patients affected by the classic PMD form carrying a PLP1 gene duplication. On the basis of clinical and neuroradiological features, two of the five patients appeared to be the most severely affected. In order to establish a possible genotype-phenotype correlation, the extent of the duplication was determined in each patient and in the respective mother by quantifying the copy number of genomic markers surrounding the PLP1 gene by a real-time PCR-based approach. Duplications, ranging in size from 167-195 to 580-700 kb, were in the same genomic interval of the majority of the reported duplications. The extent of the duplicated genomic segments does not correlate with the clinical severity. Interestingly enough, each duplication had one of the two breakpoints in or near to low copy repeats (LCRs), supporting recent evidence concerning a possible role of LCRs in the generation of the duplications in PMD.
Abstract: We describe the clinical features, muscle pathology features, and molecular studies of seven patients with Chanarin-Dorfman syndrome (CDS) or neutral lipid storage disease and ichthyosis (NLSDI), a multisystem triglyceride storage disease with massive accumulation of lipid droplets in muscle fibers. All patients presented with congenital ichthyosiform erythroderma, cytoplasmic lipid droplets in blood cells, mild to severe hepatomegaly, and increased serum CK levels and liver enzymes. Three patients showed muscle symptoms and three had steathorrea. Molecular analysis identified five mutations, three of which are novel. These findings expand the clinical and mutational spectrum and underline the genetic heterogeneity of this disease.
Abstract: This review focuses on congenital myopathies, a distinct but markedly heterogeneous group of muscle disorders that present with muscle weakness and typically appear at birth or in infancy. These myopathies have characteristic histopathologic abnormalities on muscle biopsy, allowing a preliminary morphologic classification. Advances in molecular genetics have allowed a more rational classification of these disorders and have reshuffled taxonomy for some of these conditions. Here, we focus on recent research advances in specific congenital myopathies, including nemaline myopathy, myotubular myopathy, centronuclear myopathy, central core myopathy, multi-minicore myopathy, congenital fiber-type disproportion myopathy, and hyaline body myopathy. Scientific progress has not only elucidated the pathologic mechanisms of these disorders, but it has also provided the basis for therapeutic strategies.
Abstract: Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous inherited disorders characterized by impaired neuromuscular transmission. Mutations in the acetylcholinesterase (AChE) collagen-like tail subunit gene (COLQ) cause synaptic basal-lamina associated CMS with end-plate AChE deficiency. Here we present the clinical and molecular genetic findings of 22 COLQ-mutant CMS patients, carrying a total of 20 different COLQ mutations, 11 of them had not previously been reported. Typically, patients with esterase deficiency suffer from a severe, progressive weakness with onset at birth or in early infancy. In addition, patients with a late onset showing a mild course of disease are described. AChE inhibitor therapy, beneficial for other forms of CMS, is of no effect in cases of esterase deficiency. The large cohort of COLQ patients studied here enabled us to define additional clinical presentations associated with COLQ mutations that differ from the 'classical' phenotypes: several patients with disease onset at birth or in early infancy presented an unexpected, mild disease course without significant progression of weakness. Moreover, many patients had clinical features reminiscent of limb-girdle CMS with mutations in the recently discovered DOK7 gene, including sparing of eye movements and a predominantly proximal muscle weakness. There was no long-term objective benefit from esterase inhibitors treatment in COLQ patients. Surprisingly, a short-term beneficial effect was observed in four patients and a Tensilon test was positive in two. Treatment with ephedrine was efficient in all five cases where it was administered. The variability of phenotypes caused by COLQ mutations, the divergence from the previously published classical clinical features and an initial positive response to esterase inhibitors in some patients may obscure AChE deficiency as the molecular cause of the disease and delay the start of appropriate therapy. Moreover, overlap with other CMS subtypes and potentially absence of a repetitive compound muscle action potential should be considered in the diagnosis of COLQ-mutated patients.
Abstract: Limb-girdle muscle dystrophy type 2I is associated with mutations in the gene encoding Fukutin-related protein. Clinical phenotypes are heterogeneous, ranging from isolated hyperCkemia to severe congenital muscular dystrophy. Affected patients frequently develop dilated cardiomyopathy, depending on evolution of their skeletal myopathy. We report on an 8 years-old boy presenting a severe dilated cardiomyopathy requiring heart transplantation. The child harbored a homozygous p.Leu276Ile mutation in Fukutin-related protein gene (FKRP). At the current age of 20 years, the patient shows persistent hyperCKemia but no clinical muscle weakness, CT scan showing very mild features of muscle involvement. Our findings add to the array of clinical presentations of FKRP mutations.
Abstract: The aim of the study was to conduct a survey using a dedicated questionnaire to assess feeding difficulties and weight gain in a population of 122 Spinal Muscular Atrophy (SMA) type II patients, aged between 1 and 47 years. All the answers were entered in a database and were analysed subdividing the cohort into age groups (1-5, 6-10, 11-14, 15-19, 20-29, and 30-50 years). Six out of our 122 patients (5%), all younger than 11 years, had weights more than 2SD above the median for age matched controls, whilst 45 (37%) had weights less than 2SD below the median. Chewing difficulties were reported in 34 of the 122 patients (28%) and limitation in the ability to open the mouth in 36 (30%) and both were increasingly more frequent with age. Swallowing difficulties were reported in 30 patients (25%). The results of our survey suggest that a number of patients with SMA type II have limited jaw opening, and chewing and swallowing difficulties. Our findings raise a few issues concerning standards of care that should be implemented in the monitoring and management of feeding difficulties and weight gain.
Abstract: BACKGROUND AND AIM: Oxidative stress is an important pathophysiological mechanism in non-alcoholic steatohepatitis, where hepatocyte apoptosis is significantly increased correlating with disease severity. Protein glutathionylation occurs as a response to oxidative stress, where an increased concentration of oxidized glutathione modifies post-translational proteins by thiol disulfide exchange. In this study, we analyzed the protein glutathionylation in non-alcoholic fatty liver disease (NAFLD) and evaluated a potential association between glutathionylation, fibrosis, and vitamin E treatment. METHODS: Protein glutathionylation was studied in the livers of 36 children (mean age 12.5 years, range 4-16 years) subdivided into three groups according to their NAFLD activity score (NAS) by Western blot analysis and immunohistochemistry, using a specific monoclonal antibody. In addition, we identified the hepatocyte ultrastructures involved in glutathionylation by immunogold electron microscopy. RESULTS: Our findings showed that protein glutathionylation increases in the livers of patients with NAFLD and it is correlated with steatohepatitis and liver fibrosis. Its increase appears mainly in nuclei and cytosol of hepatocytes, and it is reversed by antioxidant therapy with reduced fibrosis. CONCLUSION: Protein glutathionylation significantly increases in livers with NAFLD, strongly suggesting that oxidative injury plays a crucial role in this disease. Furthermore, the marked increase of protein glutathionylation, in correlation with collagen VI immunoreactivity, suggests a link between the redox status of hepatic protein thiols and fibrosis.
Abstract: Extensive intracranial calcifications and leukoencephalopathy are seen in both Coats plus and leukoencephalopathy with calcifications and cysts (LCC; Labrune syndrome). Coats plus syndrome is additionally characterized by the presence of bilateral retinal telangiectasia and exudates while LCC shows the progressive formation of parenchymal brain cysts. Despite these apparently distinguishing features, recent evidence suggests that Coats plus and LCC represent the same clinical entity with a common primary pathogenesis involving a small vessel obliterative microangiopathy. Here, we describe eight previously unreported cases, and present an update on one of the original Coats plus patients to highlight the emerging core clinical features of the "cerebroretinal microangiopathy with calcification and cysts" (CRMCC) phenotype.
Abstract: BACKGROUND: Pelizaeus-Merzbacher-like disease (PMLD) is a genetically heterogeneous disorder within the group of hypomyelinating leukoencephalopathies. Mutations of the gap junction protein alpha 12 (GJA12) gene are known to cause one autosomal recessive PMLD form. Few patients with GJA12 mutated PMLD have been reported, and to date, the frequency as well as the genotypic and phenotypic spectrum of GJA12 related PMLD is unclear. METHODS: We report mutation analysis of the GJA12 gene in a clinical and radiologic well-characterized multiethnic cohort of 193 patients with PMLD from 182 families. RESULTS AND CONCLUSIONS: Only 16 patients (8.3%) from 14 families (7.7%) carry GJA12 mutations including five families where we detected only one mutated allele. Among those, we identified 11 novel alterations. Thus, GJA12 mutations are a rather rare cause for Pelizaeus-Merzbacher-like disease. The clinical phenotype of patients with a GJA12 mutation was evaluated and is overall comparable to the clinical features seen in mild forms of proteolipid protein 1 (PLP1) related disorder but with better cognition and earlier signs of axonal degeneration.
Abstract: We report clinical and molecular studies on a large American family of Norwegian descent with X-linked nonprogressive congenital ataxia (XCA) in six affected males over three generations. Neuroimaging showed global cerebellar hypoplasia without evidence of supratentorial anomalies. Linkage analysis resulted in a maximum LOD score Z = 3.44 for marker DXS1192 at Theta = 0.0 with flanking markers DXS1047 and DXS1227 defining a region of 12 cM in Xq25-q27.1. The clinical and neuroradiological findings in the present family are very similar to those described in two reported X-linked families [Illarioshkin et al., 1996; Bertini et al., 2000]; however, the newly identified locus does not overlap with the one defined previously, indicating that there are at least two genes responsible for this rare form of X-linked congenital cerebellar ataxia with normal intelligence.
Abstract: A balanced redox status is necessary to optimize force production in contractile apparatus, where free radicals generated by skeletal muscle are involved in some basic physiological processes like excitation-contraction coupling. Protein glutathionylation has a key role in redox regulation of proteins and signal transduction. Here we show that myosin is sensitive to in vitro glutathionylation and MALDI-TOF analysis identified three potential sites of glutathione binding, two of them locating on the myosin head. Glutathionylation of myosin has an important impact on the protein structure, as documented by the lower fluorescence quantum yield of glutathionylated myosin and its increased susceptibility to the proteolytic cleavage. Myosin function is also sensitive to glutathionylation, which modulates its ATPase activity depending on GSSG redox balance. Thus, like the phosphorylation/dephosphorylation cycle, glutathionylation may represent a mechanism by which glutathione modulates sarcomere functions depending on the tissue redox state, and myosin may constitute a muscle redox-sensor.
Abstract: OBJECTIVE: Mutations in the gene encoding phospholipase A(2) group VI (PLA2G6) are associated with two childhood neurologic disorders: infantile neuroaxonal dystrophy (INAD) and idiopathic neurodegeneration with brain iron accumulation (NBIA). INAD is a severe progressive psychomotor disorder in which axonal spheroids are found in brain, spinal cord, and peripheral nerves. High globus pallidus iron is an inconsistent feature of INAD; however, it is a diagnostic criterion of NBIA, which describes a clinically and genetically heterogeneous group of disorders that share this hallmark feature. We sought to delineate the clinical, radiographic, pathologic, and genetic features of disease resulting from defective phospholipase A(2). METHODS: We identified 56 patients clinically diagnosed with INAD and 23 with idiopathic NBIA and screened their DNA for PLA2G6 mutations. RESULTS: Eighty percent of patients with INAD had mutations in PLA2G6, whereas mutations were found in only 20% of those with idiopathic NBIA. All patients with two null mutations had a more severe phenotype. On MRI, nearly all mutation-positive patients had cerebellar atrophy, and half showed brain iron accumulation. We observed Lewy bodies and neurofibrillary tangles in association with PLA2G6 mutations. CONCLUSION: Defects in phospholipase A(2) lead to a range of phenotypes. PLA2G6 mutations are associated with nearly all cases of classic infantile neuroaxonal dystrophy but a minority of cases of idiopathic neurodegeneration with brain iron accumulation, and genotype correlates with phenotype. Cerebellar atrophy predicts which patients are likely to be mutation-positive. The neuropathologic changes that are caused by defective phospholipase A(2) suggest a shared pathogenesis with both Parkinson and Alzheimer diseases.
Abstract: Several clinical trials assessing children with hereditary neuromuscular disorders have been performed over the last decade. These studies highlighted issues related to design and performance of clinical studies assessing children with this group of disorders. This article reviews recent literature and clinical experience in this area, highlighting methodological shortcomings and disease-specific clinical confounding factors that should be considered for future study design. The state of the art of outcome measures in neuromuscular disorders will be discussed, and suggestions for future clinical trials are presented.
Abstract: The aim of this open pilot study was to establish the profile of tolerability and clinical response of salbutamol (albuterol) in a cohort of young children affected by type II spinal muscular atrophy (SMA). Twenty-three children between 30 months and 6 years of age were treated with salbutamol (2 mg three times a day) for 1 year. All children were longitudinally assessed using the Hammersmith motor functional scale 6 months before treatment started (T0), at baseline (T1) and 6 and 12 months later. There was no significant change in function between T0 and T1 assessments, but the functional scores recorded after 6 and 12 months of treatment were significantly higher than those recorded at baseline (p=0.006). Our results suggest that salbutamol may be beneficial to SMA patients without producing any major side effect. Larger prospective randomized, double-blind, placebo controlled trials are needed to confirm these preliminary findings.
Abstract: Marfan syndrome (MFS) is an inherited disorder of connective tissue due to mutations in FBN1 (90%) and TGFBR1 and TGFBR2 (5 to 10%) genes. Clinical and differential diagnosis is difficult because of the inter- and intrafamiliar marked heterogeneity and the variable onset age of clinical manifestations. Among the disorders, in differential diagnosis, thoracic aortic aneurysm (TAA) and Ullrich scleroatonic muscular dystrophy (UCMD) are reported. We evaluate the possibility of utilizing autofluorescence (AF) analysis as a diagnostic tool in the clinical and/or differential diagnosis of MFS and related disorders and in the investigation of the molecular mechanisms involved. Both multispectral imaging autofluorescence microscopy (MIAM) and autofluorescence microspectroscopy (AMS) have been used to characterize AF emission of fibroblasts from patients affected by inherited connective tissue disorders. Our preliminary results show significant differences in AF emission between normal and pathological fibroblasts, suggesting possible improvement in diagnostics of connective tissue disorders by AF analysis.
Abstract: Joubert syndrome-related disorders (JSRDs) are autosomal recessive pleiotropic conditions sharing a peculiar cerebellar and brainstem malformation known as the 'molar tooth sign' (MTS). Recently, mutations in a novel ciliary gene, RPGRIP1L, have been shown to cause both JSRDs and Meckel-Gruber syndrome. We searched for RPGRIP1L mutations in 120 patients with proven MTS and phenotypes representative of all JSRD clinical subgroups. Two homozygous mutations, the previously reported p.T615P in exon 15 and the novel c.2268_2269delA in exon 16, were detected in 2 of 16 families with cerebello-renal presentation ( approximately 12%). Conversely, no pathogenic changes were found in patients with other JSRD phenotypes, suggesting that RPGRIP1L mutations are largely confined to the cerebello-renal subgroup, while they overall represent a rare cause of JSRD (<2%).
Abstract: Mutations in POMT1 and POMT2 genes were originally identified in Walker-Warburg syndrome (WWS) and subsequently reported in patients with milder phenotypes characterised by mental retardation with or without brain abnormalities and without ocular malformations. As part of a multicentric Italian study we screened the POMT1 and POMT2 genes in 61 congenital muscular dystrophy (CMD) patients with alpha-dystroglycan reduction on muscle biopsy and/or clinical and radiological findings suggestive of the known forms of CMD with alpha-dystroglycan deficiency. The aim of the study was to establish how frequently mutations in POMT1 and POMT2 occur in CMD patients in the Italian population and to evaluate the spectrum of associated phenotypes. Thirteen patients showed mutations in POMT1 and five harboured mutations in POMT2, accounting for a total of 20 different mutations, eight of which were novel (two in POMT1 and six in POMT2). Normal brain MRI associated with mental retardation and microcephaly was the most frequent finding in patients with mutations in POMT1 (six out of 13), but was also found in a patient with POMT2 mutations. Predominant cerebellar hypoplasia was also frequent both in patients with POMT1 (three out of 13) and POMT2 (three out of 5) mutations. A MEB phenotype with frontal cortical dysplasia and pons abnormalities was found in two patients with POMT1 and in one with POMT2 mutations, while a WWS phenotype was only found in a case with mutations in POMT1. Mutations causing frameshifts and stop codons were responsible for the more severe phenotypes. Our results provide further evidence that, as previously reported for FKRP, the array of mutations in POMT1 and POMT2 is ample and the spectrum of associated phenotypes is wider than initially thought.
Abstract: OBJECTIVE: To describe a new entity of congenital muscular dystrophies caused by de novo LMNA mutations. METHODS: Fifteen patients presenting with a myopathy of onset in the first year of life were subjected to neurological and genetic evaluation. Histopathological and immunohistochemical analyses were performed for all patients. RESULTS: The 15 patients presented with muscle weakness in the first year of life, and all had de novo heterozygous LMNA mutations. Three of them had severe early-onset disease, no motor development, and the rest experienced development of a "dropped head" syndrome phenotype. Despite variable severity, there was a consistent clinical pattern. Patients typically presented with selective axial weakness and wasting of the cervicoaxial muscles. Limb involvement was predominantly proximal in upper extremities and distal in lower extremities. Talipes feet and a rigid spine with thoracic lordosis developed early. Proximal contractures appeared later, most often in lower limbs, sparing the elbows. Ten children required ventilatory support, three continuously through tracheotomy. Cardiac arrhythmias were observed in four of the oldest patients but were symptomatic only in one. Creatine kinase levels were mild to moderately increased. Muscle biopsies showed dystrophic changes in nine children and nonspecific myopathic changes in the remaining. Markedly atrophic fibers were common, most often type 1, and a few patients showed positive inflammatory markers. INTERPRETATION: The LMNA mutations identified appear to correlate with a relatively severe phenotype. Our results further broaden the spectrum of laminopathies and define a new disease entity that we suggest is best classified as a congenital muscular dystrophy (LMNA-related congenital muscular dystrophy, or L-CMD).
Abstract: OBJECTIVE: Our aim was to assess the efficacy of noninvasive ventilation (NIV) for the treatment of thoracoabdominal asynchrony during sleep in children with spinal muscular atrophy (SMA) types 1 and 2. DESIGN: Nine subjects underwent assessment for sleep apnea/hypopnea index (AHI), mean oxyhemoglobin saturation (SpO2), oxygen desaturation index, transcutaneous carbon dioxide tension (tcpCO2), and mean phase angle during sleep as a measure of thoracoabdominal coordination. A second sleep study was performed with use of NIV. RESULTS: The nine patients (7 mos of age, range 2-33) had a baseline AHI of 2.1 events per hour (range 0.5-55.8), oxygen desaturation index of 3.7 events per hour (range 1.6-46.1), mean tcpCO2 of 46 mm Hg (range 37-60), and phase angle of 127 degrees (range 72.7-151.7). Comparing baseline and NIV sleep studies, we found significant improvement in oxygen desaturation index (P < 0.010), mean tcpCO2 (P < 0.001), and phase angle (P < 0.001). For five patients, phase-angle improvement became significant when using high-span bilevel positive airway pressure (PAP). CONCLUSIONS: NIV improved sleep breathing parameters and thoracoabdominal coordination during sleep in SMA types 1 and 2. Phase-angle improvement correlated with bilevel PAP pressures. Phase angle may be useful for the evaluation and monitoring of therapeutic interventions such as NIV.
Abstract: Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus callosum (TCC) is a common and clinically distinct form of familial spastic paraplegia that is linked to the SPG11 locus on chromosome 15 in most affected families. We analyzed 12 ARHSP-TCC families, refined the SPG11 candidate interval and identified ten mutations in a previously unidentified gene expressed ubiquitously in the nervous system but most prominently in the cerebellum, cerebral cortex, hippocampus and pineal gland. The mutations were either nonsense or insertions and deletions leading to a frameshift, suggesting a loss-of-function mechanism. The identification of the function of the gene will provide insight into the mechanisms leading to the degeneration of the corticospinal tract and other brain structures in this frequent form of ARHSP.
Abstract: One pedigree with four patients has been recently described with mitochondrial DNA depletion and mutation in SUCLA2 gene leading to succinyl-CoA synthase deficiency. Patients had a Leigh-like encephalomyopathy and deafness but besides the presence of lactic acidosis, the profile of urine organic acid was not reported. We have studied 14 patients with mild 'unlabelled' methylmalonic aciduria (MMA) from 11 families. Eight of the families are from the Faroe Islands, having a common ancestor, and three are from southern Italy. Since the reaction catalysed by succinyl-CoA synthase in the tricarboxylic acid (TCA) cycle represents a distal step of the methylmalonic acid pathway, we investigated the SUCLA2 gene as a candidate gene in our patients. Genetic analysis of the gene in the 14 patients confirmed the defect in all patients and led to the identification of three novel mutations (p.Gly118Arg; p.Arg284Cys; c.534 + 1G --> A). The defect could be convincingly shown at the protein level and our data also confirm the previously described mitochondrial DNA depletion. Defects in SUCLA2 can be found at the metabolite level and are defined by mildly elevated methylmalonic acid and C4-dicarboxylic carnitine concentrations in body fluids in association with variable lactic acidosis. Clinically the diagnosis should be considered in patients with early/neonatal onset encephalomyopathy, dystonia, deafness and Leigh-like MRI abnormalities mainly affecting the putamen and the caudate nuclei. The frequency of the mutated allele in the Faroese population amounted to 2%, corresponding with an estimated homozygote frequency of 1 : 2500. Our data extend knowledge on the genetic defects causing MMA. Our patients present with an early infantile Leigh-like encephalomyopathy with deafness, and later on a progressive dystonia. Mild MMA, lactic acidosis and specific abnormalities in the carnitine ester profile are the biochemical hallmarks of the disease. In view of the frequency of the mutated allele on the Faroe Islands, measures become feasible to prevent the occurrence of the disease on the islands. We confirm and extend the findings on this inborn error of metabolism in the TCA cycle that must be carefully investigated by accurate metabolite analyses.
Abstract: Previous studies showed that SMN2 copy number correlates inversely with the disease severity. Our aim was to evaluate SMN2 copy numbers and the Hammersmith functional motor scale in 87 patients with SMA II in order to establish whether, within SMAII, the number of copies correlates with the severity of functional impairment. Our results showed a relative variability of functional scores, but a significant correlation between the number of SMN2 genes and the level of function.
Abstract: Genome-wide gene expression profiling of skeletal muscle from Duchenne muscular dystrophy (DMD) patients has been used to describe muscle tissue alterations in DMD children older than 5 years. By studying the expression profile of 19 patients younger than 2 years, we describe with high resolution the gene expression signature that characterizes DMD muscle during the initial or "presymptomatic" phase of the disease. We show that in the first 2 years of the disease, DMD muscle is already set to express a distinctive gene expression pattern considerably different from the one expressed by normal, age-matched muscle. This "dystrophic" molecular signature is characterized by a coordinate induction of genes involved in the inflammatory response, extracellular matrix (ECM) remodeling and muscle regeneration, and the reduced transcription of those involved in energy metabolism. Despite the lower degree of muscle dysfunction experienced, our younger patients showed abnormal expression of most of the genes reported as differentially expressed in more advanced stages of the disease. By analyzing our patients as a time series, we provide evidence that some genes, including members of three pathways involved in morphogenetic signaling-Wnt, Notch, and BMP-are progressively induced or repressed in the natural history of DMD.
Abstract: Dominant mutations in the skeletal muscle ryanodine receptor (RYR1) gene are well-recognized causes of both malignant hyperthermia susceptibility (MHS) and central core disease (CCD). More recently, recessive RYR1 mutations have been described in few congenital myopathy patients with variable pathology, including multi-minicores. Although a clinical overlap between patients with dominant and recessive RYR1 mutations exists, in most cases with recessive mutations the pattern of muscle weakness is remarkably different from that observed in dominant CCD. In order to characterize the spectrum of congenital myopathies associated with RYR1 mutations, we have investigated a cohort of 44 patients from 28 families with clinical and/or histopathological features suggestive of RYR1 involvement. We have identified 25 RYR1 mutations, 9 of them novel, including 12 dominant and 13 recessive mutations. With only one exception, dominant mutations were associated with a CCD phenotype, prominent cores and predominantly occurred in the RYR1 C-terminal exons 101 and 102. In contrast, the 13 recessive RYR1 mutations were distributed evenly along the entire RYR1 gene and were associated with a wide range of clinico-pathological phenotypes. Protein expression studies in nine cases suggested a correlation between specific mutations, RyR1 protein levels and resulting phenotype: in particular, whilst patients with dominant or recessive mutations associated with typical CCD phenotypes appeared to have normal RyR1 expression, individuals with more generalized weakness, multi-minicores and external ophthalmoplegia had a pronounced depletion of the RyR1 protein. The phenomenon of protein depletion was observed in some patients compound heterozygous for recessive mutations at the genomic level and silenced another allele in skeletal muscle, providing additional information on the mechanism of disease in these patients. Our data represent the most extensive study of RYR1-related myopathies and indicate complex genotype-phenotype correlations associated with mutations differentially affecting assembly and function of the RyR1 calcium release channel.
Abstract: Neuronal ceroid lipofuscinoses (NCLs) are characterized by epilepsy, visual failure, psychomotor deterioration, and accumulation of autofluorescent lipopigment. CLN8 mutations result in Northern epilepsy and Turkish variant late infantile NCL. We describe the clinical and neurophysiological findings of three patients with CLN8 mutations from Italy. In these patients, the onset of epilepsy occurred between 3 and 6 years of age, with myoclonic, tonic-clonic, and atypical absence seizures. Electroencephalograms revealed focal and/or generalized abnormalities. In all cases, blindness and progressive attenuation of the electroretinogram were observed. Magnetic resonance imaging revealed cerebral and cerebellar atrophy, thinning of the corpus callosum, deep white matter hyperintensity, and hyperintensity of the posterior limb of internal capsules. Skin biopsy revealed lysosomal storage in the cytoplasm of fibroblasts. The clinical picture of our cases resembles that of the Turkish patients and clearly differs from that of Northern epilepsy, which is marked by a prolonged course without myoclonus and visual loss. Definition of the clinical spectrum of this condition will aid in its recognition and have implications for diagnosis and genetic counseling.
Abstract: Severe diaphragmatic weakness in infancy is rare. Common causes include structural myopathies, neuromuscular transmission defects, or anterior horn cell dysfunction (spinal muscular atrophy with respiratory distress, SMARD1). We describe a form of infantile diaphragmatic weakness without mutations in the SMARD1 gene, in which pathological and clinical features differ from known conditions, and investigations suggest a myopathy. We identified seven cases in four families. All presented soon after birth with feeding and breathing difficulties, marked head lag, facial weakness, and preserved antigravity movements in the limbs, with arms weaker than legs. All had paradoxical breathing and paralysis of at least one hemi-diaphragm. All required gastrostomy feeding, and all became ventilator-dependent. Investigations included myopathic EMG, muscle biopsy showing myopathic changes, normal electrophysiology and no mutations in SMN1 or IGHMBP2. These seven infants are affected by a myopathic condition clinically resembling SMARD1. However, its pathogenesis appears to be a myopathy affecting predominantly the diaphragm.
Abstract: OBJECTIVE: To assess the efficacy of phenylbutyrate (PB) in patients with spinal muscular atrophy in a randomized, double-blind, placebo-controlled trial involving 10 Italian centers. METHODS: One hundred seven children were assigned to receive PB (500 mg/kg/day) or matching placebo on an intermittent regimen (7 days on/7 days off) for 13 weeks. The Hammersmith functional motor scale (primary outcome measure), myometry, and forced vital capacity were assessed at baseline and at weeks 5 and 13. RESULTS: Between January and September 2004, 107 patients aged 30 to 154 months were enrolled. PB was well tolerated, with only one child withdrawing because of adverse events. Mean improvement in functional score was 0.60 in the PB arm and 0.73 in placebo arm (p = 0.70). Changes in the secondary endpoints were also similar in the two study arms. CONCLUSIONS: Phenylbutyrate was not effective at the regimen, schedule, and duration used in this study.
Abstract: BACKGROUND: Mutations in the LMNA gene, encoding human lamin A/C, have been associated with an increasing number of disorders often involving skeletal and cardiac muscle, but no clear genotype/phenotype correlation could be established to date. METHODS: We analyzed the LMNA gene in a large cohort of patients mainly affected by neuromuscular or cardiac disease and clustered mutated patients in two groups to unravel possible correlations. RESULTS: We identified 28 variants, 9 of which reported for the first time. The two groups of patients were characterized by clinical and genetic differences: 1) patients with childhood onset displayed skeletal muscle involvement with predominant scapuloperoneal and facial weakness associated with missense mutations; 2) patients with adult onset mainly showed cardiac disorders or myopathy with limb girdle distribution, often associated with frameshift mutations presumably leading to a truncated protein. CONCLUSIONS: Our findings, supported by meta-analysis of previous literature, suggest the presence of two different pathogenetic mechanisms: late onset phenotypes may arise through loss of function secondary to haploinsufficiency, while dominant negative or toxic gain of function mechanisms may explain the severity of early phenotypes. This model of patient stratification may help patient management and facilitate future studies aimed at deciphering lamin A/C pathogenesis.
Abstract: Primary coenzyme Q(10) (CoQ(10)) deficiency includes a group of rare autosomal recessive disorders primarily characterized by neurological and muscular symptoms. Rarely, glomerular involvement has been reported. The COQ2 gene encodes the para-hydroxybenzoate-polyprenyl-transferase enzyme of the CoQ(10) synthesis pathway. We identified two patients with early-onset glomerular lesions that harbored mutations in the COQ2 gene. The first patient presented with steroid-resistant nephrotic syndrome at the age of 18 months as a result of collapsing glomerulopathy, with no extrarenal symptoms. The second patient presented at five days of life with oliguria, had severe extracapillary proliferation on renal biopsy, rapidly developed end-stage renal disease, and died at the age of 6 months after a course complicated by progressive epileptic encephalopathy. Ultrastructural examination of renal specimens from these cases, as well as from two previously reported patients, showed an increased number of dysmorphic mitochondria in glomerular cells. Biochemical analyses demonstrated decreased activities of respiratory chain complexes [II+III] and decreased CoQ(10) concentrations in skeletal muscle and renal cortex. In conclusion, we suggest that inherited COQ2 mutations cause a primary glomerular disease with renal lesions that vary in severity and are not necessarily associated with neurological signs. COQ2 nephropathy should be suspected when electron microscopy shows an increased number of abnormal mitochondria in podocytes and other glomerular cells.
Abstract: Sjögren-Larsson syndrome (SLS; MIM#270200) is an autosomal recessive neurocutaneous disease caused by mutations in the ALDH3A2 gene for fatty aldehyde dehydrogenase (FALDH), a microsomal enzyme that catalyzes the oxidation of medium- and long- chain aliphatic aldehydes fatty acids. We studied two unrelated Italian SLS patients with ichthyosis, developmental delay, spastic diplegia and brain white matter disease. One patient was homozygous for a novel ALDH3A2 insertion mutation (c.767insA) in exon 5. The other SLS patient was a compound heterozygote for two previously reported mutations: a slice site mutation (c.1094C > T; S365L) in exon 7. Analysis of fibroblast RNA by RT-PCR indicated that the spice-site mutation caused skipping of exons 2 and 3. The c.1094C > T mutation, previously associated with two ALDH3A2 haplotypes, was found on a third distinct haplotype in our patient, which indicates that arose independently in this kindred. These results add to understanding of the genetic basis of SLS and will be useful for DNA diagnosis of this disease.
Abstract: BACKGROUND: Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare disorder characterized by episodic hyperkinetic movement attacks. We have recently identified mutations in the MR-1 gene causing familial PNKD. METHODS: We reviewed the clinical features of 14 kindreds with familial dyskinesia that was not clearly induced by movement or during sleep. Of these 14 kindreds, 8 had MR-1 mutations and 6 did not. RESULTS: Patients with PNKD with MR-1 mutations had their attack onset in youth (infancy and early childhood). Typical attacks consisted of a mixture of chorea and dystonia in the limbs, face, and trunk, and typical attack duration lasted from 10 minutes to 1 hour. Caffeine, alcohol, and emotional stress were prominent precipitants. Attacks had a favorable response to benzodiazepines, such as clonazepam and diazepam. Attacks in families without MR-1 mutations were more variable in their age at onset, precipitants, clinical features, and response to medications. Several were induced by persistent exercise. CONCLUSIONS: Paroxysmal nonkinesigenic dyskinesia (PNKD) should be strictly defined based on age at onset and ability to precipitate attacks with caffeine and alcohol. Patients with this clinical presentation (which is similar to the phenotype initially reported by Mount and Reback) are likely to harbor myofibrillogenesis regulator 1 (MR-1) gene mutations. Other "PNKD-like" families exist, but atypical features suggests that these subjects are clinically distinct from PNKD and do not have MR-1 mutations. Some may represent paroxysmal exertional dyskinesia.
Abstract: Spinal muscular atrophy is a neurodegenerative disease that requires multidisciplinary medical care. Recent progress in the understanding of molecular pathogenesis of spinal muscular atrophy and advances in medical technology have not been matched by similar developments in the care for spinal muscular atrophy patients. Variations in medical practice coupled with differences in family resources and values have resulted in variable clinical outcomes that are likely to compromise valid measure of treatment effects during clinical trials. The International Standard of Care Committee for Spinal Muscular Atrophy was formed in 2005, with a goal of establishing practice guidelines for clinical care of these patients. The 12 core committee members worked with more than 60 spinal muscular atrophy experts in the field through conference calls, e-mail communications, a Delphi survey, and 2 in-person meetings to achieve consensus on 5 care areas: diagnostic/new interventions, pulmonary, gastrointestinal/nutrition, orthopedics/rehabilitation, and palliative care. Consensus was achieved on several topics related to common medical problems in spinal muscular atrophy, diagnostic strategies, recommendations for assessment and monitoring, and therapeutic interventions in each care area. A consensus statement was drafted to address the 5 care areas according to 3 functional levels of the patients: nonsitter, sitter, and walker. The committee also identified several medical practices lacking consensus and warranting further investigation. It is the authors' intention that this document be used as a guideline, not as a practice standard for their care. A practice standard for spinal muscular atrophy is urgently needed to help with the multidisciplinary care of these patients.
Abstract: Aicardi-Goutieres syndrome (AGS) is a genetic encephalopathy whose clinical features mimic those of acquired in utero viral infection. AGS exhibits locus heterogeneity, with mutations identified in genes encoding the 3'-->5' exonuclease TREX1 and the three subunits of the RNASEH2 endonuclease complex. To define the molecular spectrum of AGS, we performed mutation screening in patients, from 127 pedigrees, with a clinical diagnosis of the disease. Biallelic mutations in TREX1, RNASEH2A, RNASEH2B, and RNASEH2C were observed in 31, 3, 47, and 18 families, respectively. In five families, we identified an RNASEH2A or RNASEH2B mutation on one allele only. In one child, the disease occurred because of a de novo heterozygous TREX1 mutation. In 22 families, no mutations were found. Null mutations were common in TREX1, although a specific missense mutation was observed frequently in patients from northern Europe. Almost all mutations in RNASEH2A, RNASEH2B, and RNASEH2C were missense. We identified an RNASEH2C founder mutation in 13 Pakistani families. We also collected clinical data from 123 mutation-positive patients. Two clinical presentations could be delineated: an early-onset neonatal form, highly reminiscent of congenital infection seen particularly with TREX1 mutations, and a later-onset presentation, sometimes occurring after several months of normal development and occasionally associated with remarkably preserved neurological function, most frequently due to RNASEH2B mutations. Mortality was correlated with genotype; 34.3% of patients with TREX1, RNASEH2A, and RNASEH2C mutations versus 8.0% RNASEH2B mutation-positive patients were known to have died (P=.001). Our analysis defines the phenotypic spectrum of AGS and suggests a coherent mutation-screening strategy in this heterogeneous disorder. Additionally, our data indicate that at least one further AGS-causing gene remains to be identified.
Abstract: Joubert syndrome-related disorders (JSRDs) are a group of clinically and genetically heterogeneous conditions that share a midbrain-hindbrain malformation, the molar tooth sign (MTS) visible on brain imaging, with variable neurological, ocular, and renal manifestations. Mutations in the CEP290 gene were recently identified in families with the MTS-related neurological features, many of which showed oculo-renal involvement typical of Senior-Loken syndrome (JSRD-SLS phenotype). Here, we performed comprehensive CEP290-mutation analysis on two nonoverlapping cohorts of JSRD-affected patients with a proven MTS. We identified mutations in 19 of 44 patients with JSRD-SLS. The second cohort consisted of 84 patients representing the spectrum of other JSRD subtypes, with mutations identified in only two patients. The data suggest that CEP290 mutations are frequently encountered and are largely specific to the JSRD-SLS subtype. One patient with mutation displayed complete situs inversus, confirming the clinical and genetic overlap between JSRDs and other ciliopathies.
Abstract: Neuronal ceroid lipofuscinoses (NCLs) are relatively common storage diseases of childhood and early adolescence. Ultrastructural shape of storage cytosomes, type of disease gene, and age of onset serve to classify the different NCLs, some of which appear to cluster in Scandinavian countries. The CLN5 form usually presents as a classical epileptiform encephalopathy of late infancy but a more aggressive cognitive impairment has been described in a single family. We report two sibs harbouring a novel mutation (p.Tyr258Asp) in the CLN5 gene and displaying behaviour disturbances and mental deterioration, rather than epilepsy, as the dominant disease manifestation at onset.
Abstract: Ullrich congenital muscular dystrophy (UCMD) is clinically characterized by muscle weakness, proximal contractures and distal hyperlaxity and morphologically branded by absence or reduction of collagen VI (ColVI), in muscle and in cultured fibroblasts. The ColVI defect is generally related to COL6 genes mutations, however UCDM patients without COL6 mutations have been recently reported, suggesting genetic heterogeneity. We report comparative morphological findings between a UCMD patient harboring a homozygous COL6A2 mutation and a patient with a typical UCMD phenotype in which mutations in COL6 genes were excluded. The patient with no mutations in COL6 genes exhibited a partial ColVI defect, which was only detected close to the basal membrane of myofibers. We describe how confocal microscopy and rotary-shadowing electron microscopy may be useful to identify a secondary ColVI defect.
Abstract: In a newborn with severe respiratory failure and abnormal elevation of the right diaphragm, congenital diaphragmatic hernia with sac was diagnosed during surgery. However, microscopic examination of the sac showed atrophic striated muscle cells, indicating eventration instead of hernia. After several extubation failures, the final diagnosis of nemaline myopathy was made by skeletal muscle biopsy. In diaphragmatic defects with sac, diaphragm microscopic analysis should be recommended in order to discriminate between hernia and eventration. Congenital myopathies may underlie such diaphragmatic defects and should be promptly recognized, given their prognostic implications.
Abstract: Nine new unrelated patients presenting vacuolating myelinopathy with subcortical cysts were identified and analyzed for variations in the MLC1 gene. We detected 12 mutations (p.Leu37fs, p.Met80Val, p.Leu83Phe, p.Pro92Ser, p.Ser93Leu, p.Ile108fs, p.Gly130Arg, p.Cys171fs, p.Glu202Lys, p.Ser269Tyr, p.Ala275Asn, and p.Leu310_311insLeu) of which nine were novel. In one patient we did not detect mutations. Using a heterologous system, three new missense variants (p.Glu202Lys, p.Ser269Tyr, and p.Ala275Asn) and a single leucine insertion (p.Leu310insLeu)--lying in a stretch of seven leucines--were functionally assayed by determining total protein levels and mutant protein expression at the plasma membrane. No correlation was observed between mutation, clinical features, and plasma membrane expression of mutant protein.
Abstract: OBJECTIVE: Joubert syndrome (JS) is a recessively inherited developmental brain disorder with several identified causative chromosomal loci. It is characterized by hypoplasia of the cerebellar vermis and a particular midbrain-hindbrain "molar tooth" sign, a finding shared by a group of Joubert syndrome-related disorders (JSRDs), with wide phenotypic variability. The frequency of mutations in the first positionally cloned gene, AHI1, is unknown. METHODS: We searched for mutations in the AHI1 gene among a cohort of 137 families with JSRD and radiographically proven molar tooth sign. RESULTS: We identified 15 deleterious mutations in 10 families with pure JS or JS plus retinal and/or additional central nervous system abnormalities. Mutations among families with JSRD including kidney or liver involvement were not detected. Transheterozygous mutations were identified in the majority of those without history of consanguinity. Most mutations were truncating or splicing errors, with only one missense mutation in the highly conserved WD40 repeat domain that led to disease of similar severity. INTERPRETATION: AHI1 mutations are a frequent cause of disease in patients with specific forms of JSRD.
Abstract: Neuronal ceroid lipofuscinoses (NCLs) are autosomal recessive neurodegenerative disorders typically characterized by the accumulation of autofluorescent material in tissues. On the basis of clinical features, age at onset, and molecular genetic defects, it is possible to distinguish at least nine forms. The CLN8 form was first described in Finland, where all the patients are homozygous for a p.Arg24Gly mutation in CLN8. More recently, it has been found that a subset of a Turkish variant of late infantile NCL (v-LINCL) is also associated with CLN8 mutations. To identify the molecular defect in Italian patients with v-LINCL, the CLN8 gene was directly sequenced in 10 patients. Controls were screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Five fluorescent-labeled microsatellite markers covering 1 cM around the gene were used for haplotype analysis. In three Italian v-LINCL patients, identified in a small area in southern Italy, we detected four new mutations in CLN8: c.66delG (p.Gly22fs), c.88G>C (p.Ala30Pro), c.473A>G (p.Tyr158Cys), and c.581A>G (p.Gln194Arg). The single-base deletion was found in two unrelated patients. The novel missense mutations were not identified in ethnically matched control chromosomes. Our findings expand the number of CLN8 variants and corroborate the notion that CLN8 patients are not confined to the Finnish population.
Abstract: The importance of O-glycosylation of alpha-dystroglycan (alpha-DG) is evident from the identification of POMT1 mutations in Walker-Warburg syndrome (WWS). Approximately one-fifth of the WWS patients show mutations in POMT1, which result in complete loss of protein mannosyltransferase activity. WWS patients are characterized by congenital muscular dystrophy (CMD) with severe brain and eye abnormalities. This suggests a crucial role for alpha-DG during development of these organs and tissues. Here we report new POMT1 mutations and polymorphisms in WWS patients. In addition, we report different compound heterozygous POMT1 mutations in four unrelated families that result in a less severe phenotype than WWS, characterized by CMD with calf hypertrophy, microcephaly, and mental retardation. Compared to WWS patients, these patients have milder structural brain abnormalities, and eye abnormalities were absent, except for myopia in some cases. In these patients we postulate that one or both transcripts for POMT1 confer residual protein O-mannosyltransferase activity. Our data suggest the existence of a disease spectrum of CMD including brain and eye abnormalities resulting from POMT1 mutations.
Abstract: Joubert syndrome-related disorders (JSRD) are a group of syndromes sharing the neuroradiological features of cerebellar vermis hypoplasia and a peculiar brainstem malformation known as the 'molar tooth sign'. We identified mutations in the CEP290 gene in five families with variable neurological, retinal and renal manifestations. CEP290 expression was detected mostly in proliferating cerebellar granule neuron populations and showed centrosome and ciliary localization, linking JSRDs to other human ciliopathies.
Abstract: The inherited disorders of CNS myelin formation represent a heterogeneous group of leukodystrophies. The proteolipoprotein (PLP1) gene has been implicated in two X-linked forms, Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia type 2, and the gap junction protein alpha12 (GJA12) gene in a recessive form of PMD. The myelin basic protein (MBP) gene, which encodes the second most abundant CNS myelin protein after PLP1, presents rearrangements in hypomyelinating murine mutants and is always included in the minimal region deleted in 18q- patients with an abnormal hypomyelination pattern on cerebral MRI. In this study, we looked at the genomic copy number at the Golli-MBP locus in 195 patients with cerebral MRI suggesting a myelin defect, who do not have PLP1 mutation. Although preliminary results obtained by FISH suggested the duplication of Golli-MBP in 3 out of 10 patients, no abnormal gene quantification was found using Quantitative Multiplex PCR of Short Fluorescent fragments (QMPSF), Multiplex Amplifiable Probe Hybridization (MAPH), or another FISH protocol using directly-labelled probes. Pitfalls and interest in these different techniques to detect duplication events are emphasised. Finally, the study of this large cohort of patients suggests that Golli-MBP deletion or duplication is rarely involved in inherited defects of myelin formation.
Abstract: We studied 20 Mediterranean families (40 patients) with autosomal recessive hereditary spastic paraplegia and thin corpus callosum (ARHSP-TCC, MIM 604360) to characterize their clinical and genetic features. In six families (17 patients) of Algerian Italian, Moroccan, and Portuguese ancestry, we found data consistent with linkage to the SPG11 locus on chromosome 15q13-15, whereas, in four families (nine patients of Italian, French, and Portuguese ancestry) linkage to the SPG11 locus could firmly be excluded, reinforcing the notion that ARHSP-TCC is genetically heterogeneous. Patients from linked and unlinked families could not be distinguished on the basis of clinical features alone. In SPG11-linked kindred, haplotype reconstruction allowed significant refinement to 6 cM, of the minimal chromosomal interval, but analysis of two genes (MAP1A and SEMA6D) in this region did not identify causative mutations. Our findings suggest that ARHSP-TCC is the most frequent form of ARHSP in Mediterranean countries and that it is particularly frequent in Italy.
Abstract: Kearns-Sayre syndrome (KSS) is a mitochondrial disease caused by large deletions in mitochondrial DNA (mtDNA). In most patients the disease is characterized by mtDNA heteroplasmy, where a mixture of wild-type and mutated mtDNA co-exist within cells in variable proportion, modulating the severity of the phenotype in different tissues. We report on the case of a 14-year-old child with classical symptoms of KSS and a renal phenotype characterized by hypokalaemic alkalosis, hypomagnesaemia, hyperreninaemia, hyperaldosteronism and nephrocalcinosis, resembling Bartter syndrome. Analysis of mtDNA demonstrated an 8,661 bp deletion involving eight mitochondrial genes. Uneven degrees of mtDNA heteroplasmy were demonstrated in several tissues, ranging from 24% to 60% of deleted/total mtDNA. Variable degrees of expression of mitochondrial enzymes were also found in biopsy specimens of renal and skeletal muscle by histocytochemistry. In particular, preserved cytochrome c oxidase was observed in tubular structures within medullary rays. It is proposed that a "Bartter-like" phenotype can arise in some patients with KSS as a result of heteroplasmy. In these cases aldosterone-responsive tubular structures have been spared during renal embryogenesis, allowing for the development of hypokalaemic alkalosis in response to salt and water losses from the more damaged tubular segments.
Abstract: OBJECTIVE: Methods: We describe biochemically and clinically relevant aspects of mitochondrial ATP synthase, the enzyme that supplies most ATP for the cells energy demand. RESULTS: Analyzing human Rho zero cells we could identify three subcomplexes of ATP synthase: F1 catalytic domain, F1 domain with bound natural IF1 inhibitor protein, and F1-c subcomplex, an assembly of F1 domain and a ring of F(O)-subunits c. Large amounts of F1 subcomplexes accumulated also in mitochondria of patients with specific mitochondrial disorders. By quantifying the F1 subcomplexes and other oxidative phosphorylation complexes in parallel, we were able to discriminate three classes of defects in mitochondrial biosynthesis, namely, mitochondrial DNA depletion, mitochondrial transfer RNA (tRNA) mutations, and mutations in the mitochondrial ATP6 gene. INTERPRETATION: The relatively simple electrophoretic assay used here is a straightforward approach to differentiate between various types of genetic alterations affecting the biosynthesis of oxidative phosphorylation complexes and will be useful to guide molecular genetic diagnostics in the field of mitochondrial neuromuscular disorders.
Abstract: Neuronal defense against free radicals is mediated primarily by the glutathione system. A cerebral defect of this system gives rise to the oxidative stress occurring in some neurological diseases. Glutathione provides a means of regulating protein function by glutathionylation, consisting of the formation of mixed disulfides between cysteines and glutathione. The glutathionylation of proteins, during both constitutive metabolism and oxidative stress, represents for the cell a mechanism to link physiological processes, and/or adaptive stress responses, to changes in intracellular redox states. In this study, we analyzed the topographic distribution of the protein glutathionylation normally occurring in human central nervous system. Constitutively glutathionylated proteins appeared uniformly distributed throughout all cortical layers of the cerebral and cerebellar cortex as well as throughout the gray matter of the spinal cord. The degree of immunocytochemical staining was clear in neurons, mild in oligodendrocytes, and weaker in astrocytes. The proteins preferentially glutathionylated were cytoskeletal proteins. Our results suggest a potential role of glutathionylation in the redox regulation of neuronal survival and in the control of axon/dendrite stability.
Abstract: The proteolipid protein 1 (PLP1) gene is known to be mutated in the X-linked disorders of myelin formation Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia type 2. The most commonly found PLP1 mutations are gene duplications (60-70%) and point mutations (20%). About 20% of patients with a PMD phenotype do not present identified PLP1 mutation, thus suggesting genetic heterogeneity and/or undetected PLP1 abnormalities. Except the recently described MLPA screening the seven exonic regions, the currently used techniques to quantify PLP1 gene copy number do not investigate small intragenic PLP1 rearrangements. Using the multiplex amplifiable probe hybridization (MAPH) technique, we looked simultaneously for intragenic rearrangements along the PLP1 gene (exonic and regulatory regions) and for rearrangements in the GPM6B candidate gene (a member of the proteolipid protein family). We tested 262 hypomyelinating patients: 56 PLP1 duplicated patients, 1 PLP1 triplicated patient, and 205 patients presenting a leukodystrophy of undetermined origin with brain MRI suggesting a defect in myelin formation. Our results show that MAPH is an alternative reliable technique for diagnosis of PLP1 gene copy number. It allows us (1) to demonstrate that all PLP1 duplications previously found encompass the whole gene, (2) to establish that copy number changes in GPM6B and intragenic duplications of PLP1 are very unlikely to be involved in the etiology of UHL, and (3) to identify one partial triplication and two partial deletions of PLP1 in patients presenting with a PMD phenotype.
Abstract: The aim of this study was to validate the Hammersmith functional motor scale for children with spinal muscular atrophy in a large cohort of 90 non-ambulant children with spinal muscular atrophy type 2 or 3. All had a baseline assessment (T0) and were reassessed either at 3 months (T1) (n = 66) or at 6 months (T2) (n = 24). Inter-observer reliability, tested on 13 children among 3 examiners, was > 95%. Of the 66 children examined after 3 months 4 had adverse effects in between assessments and were excluded from the analysis. Forty-two (68%) of the remaining 62 reassessed had no variation in scores between T0 and T1 and 13 (21%) were within +/- 1 point. 9 (37.5%) of the 24 children reassessed after 6 months had no variation in scores between T0 and T2 and another 9 (37.5%) had variations within +/- 1 point. Our study confirms previous observations of the reliability of the scale and helps to establish a baseline for assessing changes of functional ability over 3 and 6 month intervals. This information can be valuable in view of therapeutic trials.
Abstract: Severe Myoclonic Epilepsy in Infancy (SMEI) is an intractable epileptic syndrome with onset in the first year of life and is commonly caused by de novo mutations in the SCN1A gene, encoding the alpha1-subunit of the neuronal voltage-gated sodium channel. We report two unrelated families in which probands were affected by SMEI and their parents showed a single febrile seizure during early childhood or no neurological symptoms. Semiquantitative analysis of SCN1A mutations allowed the detection of a somatic and germline mosaicism in one of the parents. The study provides the first example of parental mosaicisms in SMEI and opens a new insight into the phenotypic variability and complex inheritance of this condition. The identification of germline mosaicisms has important consequences in genetic counseling of SMEI when SCN1A mutations appear to occur de novo with standard screening methods.
Abstract: BACKGROUND: Bethlem myopathy is considered a relatively mild neuromuscular disorder without significant cardiac and respiratory involvement. OBJECTIVE: To investigate cardiac and respiratory involvement in Bethlem myopathy. DESIGN: Cross-sectional study. SETTING: University hospitals. Patients Fifty patients with Bethlem myopathy from 26 families. INTERVENTIONS: Cardiac examinations, including electrocardiography and echocardiography (n = 37) and pulmonary investigations (n = 43). Holter monitoring was performed in 16 patients. MAIN OUTCOME MEASURES: Cardiac and respiratory abnormalities. RESULTS: Several cardiac abnormalities were found that were considered unrelated to the muscular disorder. Seven (16%) of 43 patients had a forced vital capacity less than 70% of the predicted value. One of 2 patients with a forced vital capacity less than 50% was also receiving respiratory support. All patients with compromised respiratory function were still ambulatory, and we found no significant correlation between the severity of arm weakness and the severity of respiratory muscle involvement. CONCLUSIONS: There is no evidence of cardiac involvement in Bethlem myopathy. Respiratory failure is part of the clinical spectrum and can occur in ambulatory patients.
Abstract: BACKGROUND: Muscle-eye-brain disease is a congenital muscular dystrophy with eye and brain involvement due to POMGnT1 mutations. OBJECTIVE: To describe the clinical and molecular features of 3 Italian patients with POMGnT1 mutations. DESIGN: Case reports. PATIENTS: One patient had muscle and brain abnormalities without eye involvement. Two patients had a classic muscle-eye-brain disease phenotype with different levels of clinical severity. RESULTS: Brain magnetic resonance imaging showed cortical malformation and posterior fossa involvement. Immunofluorescence for glycosylated alpha-dystroglycan performed on muscle biopsy specimens demonstrated an absent signal in 1 patient and reduced staining in 2 patients. Molecular analysis identified 5 mutations, 2 of which are novel. CONCLUSION: This article adds to what is known about the genotype-phenotype correlation and expands our awareness of the clinical spectrum associated with POMGnT1 mutations.
Abstract: We report on a 2-year-old male child with both nemaline myopathy and hypertrophic cardiomyopathy (HCM). Sequencing of the ACTA1 gene showed a "de novo" missense heterozygous mutation a>g in exon 7 (Lys336Glu). Two-dimensional electrophoresis showed 28% mutant actin present in his muscle biopsy. Actin was isolated from the muscle biopsy and examined by in vitro motility assay. The sliding speed was 13+/-3% less than normal and the affinity of actin for the Z-line protein alpha-actinin was reduced 10 fold. This is the first report on a hypertrophic cardiomyopathy associated with nemaline myopathy and an ACTA1 mutation.
Abstract: PURPOSE: The role of the familial background in severe myoclonic epilepsy of infancy (SMEI) has been traditionally emphasized in literature, with 25-70% of the patients having a family history of febrile seizures (FS) or epilepsy. We explored the genetic background of SMEI patients carrying SCN1A mutations to further shed light on the genetics of this disorder. METHODS: We analyzed the occurrence of FS and epilepsy among first- and second-degree relatives (N = 867) of 74 SMEI probands with SCN1A mutations (70 de novo, four inherited) and compared data with age-matched and ethnically matched control families. Familial clustering and syndromic concordance within the affected relatives in both groups were investigated. RESULTS: The frequency of FS or epilepsy in relatives of SMEI patients did not significantly differ from that in controls (FS: 13 of 867 vs. 12 of 674, p = 0.66; epilepsy: 15 of 867 vs. six of 674, p = 0.16). Different forms of epilepsy were identified in both relatives of SMEI probands and controls. Twenty-eight relatives with FS and epilepsy were distributed in 20 (27%) of 74 SMEI families; among the controls, 18 affected relatives were clustered in 13 (18.5%) of 70 families. No pedigree showed several affected members, including the four with inherited mutations. CONCLUSIONS: A substantial epileptic family background is not present in our SMEI patients with SCN1A mutations. These data do not confirm previous observations and would not support polygenic inheritance in SMEI. The investigation of the family background in additional series of SMEI patients will further shed light on the genetics of this syndrome.
Abstract: This paper summarizes observations on the genetic and biochemical basis of hereditary defects of complex I (NADH-ubiquinone oxidoreductase) of the respiratory chain in human neurological patients. Two different types of functional defects of the complex are described. In one type mutations in the NDUFS1 and NDUFS4 nuclear structural genes of the complex were identified in two unrelated families. Both NDUFS1 and NDUFS4 neurological disorders were transmitted by autosomic recessive inheritance. The two mutations resulted in different impact on cellular metabolism. The NDUFS4 mutation, giving a more severe, fatal pathological pattern, resulted in a defective assembly of the complex and complete suppression of the enzymatic activity. The NDUFS1 mutation, with less severe progressive pathology, caused only partial inhibition of the complex but enhanced production of oxygen free radicals. In the second type of deficiencies extensive mutational analysis did not reveal pathogenic mutations in complex I genes but a decline in the level and activity of complex I, III, and IV were found, apparently associated with alteration in the cardiolipin membrane distribution.
Abstract: Mutations in POMT2 have so far only been reported in patients with Walker-Warburg phenotype. We report heterozygous POMT2 mutations in an a girl with a milder phenotype characterized by mental retardation, microcephaly, hypertrophy of the quadriceps and calf muscles, and structural brain changes mostly affecting the posterior fossa. Our findings suggest that, as previously reported for POMT1 and FKRP, mutations in the POMT2 can also be associated with clinical heterogeneity.
Abstract: Type 1 nephronophthisis (NPHP) with homozygous deletions of nephrocystin [NPHP1, DEL] has been considered a pure renal disorder, but co-occurrence of extrarenal symptoms, mainly retinitis pigmentosa, is observed in a subset of patients. Recently, [NPHP1, DEL] has been detected in three patients with Joubert syndrome-related disorders (JSRDs), who associated neurological signs with a peculiar neuroradiological malformation known as the 'molar tooth sign' (MTS). To define the frequency of JSRD spectrum in NPHP1 patients, we re-examined 56 cases with [NPHP1, DEL] and found an overall incidence of 8.9% (five out 56 patients). All had small hyperechoic kidneys and had developed advanced renal failure within 15 years. Two patients presented the complete features of JSRD with cerebello-renal-retinal association and MTS. Two others showed, instead, severe intentional tremor and thick superior cerebellar peduncles on brain magnetic resonance imaging (MRI), and one of them had associated retinopathy. The fifth patient presented with hypotonia, developmental delay, central deafness, and ataxia associated with Leber congenital amaurosis and liver fibrosis but with normal brain MRI. Marked intrafamilial variability of associated extrarenal symptoms was observed in familial cases. Deletion extension did not differ in patients with isolated renal phenotype and in those with associated neurological symptoms. In conclusion, neurological defects varying from subtle involvement of cerebellum with thickened peduncle to both JSRD and diffuse central hypotonia are frequent in [NPHP1, DEL] patients. Prevalence of such association may justify systematic neurological and neuroradiological evaluation.
Abstract: We have characterized at the molecular level, three families with core myopathies carrying apparent recessive mutations in their RYR1 gene and studied the pharmacological properties of myotubes carrying endogenous mutations as well as the properties of mutant channels expressed in HEK293 cells. The proband of family 1 carried p.Ala1577Thr+p.Gly2060Cys in trans, having inherited a mutation from each parent. Immunoblot analysis of proteins from the patient's skeletal muscle revealed low levels of ryanodine receptor (RyR1) but neither substitution alone or in combination affected the functional properties of RyR1 channels in a discernable way. Two affected siblings in family 2 carried p.Arg109Trp+p.Met485Val substitutions in cis, inherited from the unaffected father. Interestingly, both affected siblings only transcribed the mutated paternal allele in skeletal muscle, whereas the maternal allele was silent. Single-channel measurements showed that recombinant, mutant RyR1 channels carrying both substitutions lost the ability to conduct Ca2+. In this case as well, low levels of RyR1 were present in skeletal muscle extracts. The proband of family 3 carried p.Ser71Tyr+p.Asn2283His substitutions in trans. Recombinant channels with Asn2283His substitution showed an increased activity, whereas recombinant channels with p.Ser71Tyr+p.Asn2283His substitution lost activity upon isolation. Taken together, our data suggest major differences in the ways RYR1 mutations may affect patients with core myopathies, by compromising RyR1 protein expression, stability and/or activity.
Abstract: 3-Methylglutaconic aciduria is the biochemical marker of several inherited metabolic diseases. Four types of 3-methylglutaconic aciduria can be distinguished. In the type I form, accumulation of 3-methylglutaconate is due to deficient activity of 3-methylglutaconyl-CoA hydratase, an enzyme of the leucine degradation pathway. In the other forms, 3-methylglutaconic acid is not derived from leucine but is of unidentified origin, possibly derived from other metabolic pathways, such as mevalonate metabolism. We report five patients, all presenting a severe early-onset phenotype characterized by 3-methylglutaconic aciduria, hypertrophic cardiomyopathy, cataract, hypotonia/developmental delay, lactic acidosis, and normal 3-methylglutaconyl-CoA hydratase activity. This peculiar phenotype, for which a primary mitochondrial disorder is hypothesized, identifies a novel subtype of 3-methylglutaconic aciduria.
Abstract: Mutations in POMT1 have been identified in Walker-Warburg syndrome and in patients with limb-girdle muscular dystrophy and mental retardation (LGMD2K). The authors report new POMT1 mutations in three unrelated children with severe motor impairment, leg hypertrophy, and mental retardation but without brain and ocular malformations. These patients are similar to LGMD2K but have earlier onset and more severe motor disability. The current findings expand the spectrum of POMT1-associated phenotypes.
Abstract: Aicardi-Goutières syndrome (AGS) is an autosomal recessive neurological disorder, the clinical and immunological features of which parallel those of congenital viral infection. Here we define the composition of the human ribonuclease H2 enzyme complex and show that AGS can result from mutations in the genes encoding any one of its three subunits. Our findings demonstrate a role for ribonuclease H in human neurological disease and suggest an unanticipated relationship between ribonuclease H2 and the antiviral immune response that warrants further investigation.
Abstract: POU genes play a prominent role in the nervous system differentiation of several organism models, and in particular, they are involved in the differentiation of sensory neurons in numerous invertebrate and vertebrate species. In the present report, cloning and expression profile of a class IV POU gene in amphioxus was assessed for understanding its role in the sensory systems development. A single class IV gene, AmphiPOU-IV was isolated from the amphioxus Branchiostoma floridae. From a phylogenetic point of view, AmphiPOU-IV appears to be strictly related to the vertebrate one, sharing a high homology ratio especially with all vertebrate POU-IV proteins Brn-3a, Brn-3b, and Brn-3c. AmphiPOU-IV was found in the most anterior neural plate and in scattered ectodermic cells on the flanks of neurula, such ectodermic cells resemble the characteristic morphology and position of AmphiCoe and AmphiTrk developing sensory cells. Later on, the expression was confined in some motoneurons at level of the PMC and in some segmental arranged motoneurons in the hindbrain. Such expression is also maintained in larvae, and a new site of AmphiPOU-IV expression was also found in rostrum and mouth edge epidermal sensory cells of the larva. In conclusion, our data suggest an evolutionary conserved role of POU-IV transcription factors in the specification and differentiation of the sensory system in both vertebrates and invertebrates and underline the importance of amphioxus as linking step between them.
Abstract: Neurodegenerative disorders with high brain iron include Parkinson disease, Alzheimer disease and several childhood genetic disorders categorized as neuroaxonal dystrophies. We mapped a locus for infantile neuroaxonal dystrophy (INAD) and neurodegeneration with brain iron accumulation (NBIA) to chromosome 22q12-q13 and identified mutations in PLA2G6, encoding a calcium-independent group VI phospholipase A2, in NBIA, INAD and the related Karak syndrome. This discovery implicates phospholipases in the pathogenesis of neurodegenerative disorders with iron dyshomeostasis.
Abstract: In this study, we characterized five Ullrich scleroatonic muscular dystrophy patients (two Italians, one Belgian, and two Turks) with a clinical phenotype showing different degrees of severity, all carrying mutations localized in COL6A1. We sequenced the three entire COL6 complementary DNA. Three of five patients have recessive mutations: two patients (P1and P3) have homozygous single-nucleotide deletions, one in exon 9 and one in exon 22; one patient (P2) has a homozygous single-nucleotide substitution leading to a premature termination codon in exon 31. The nonsense mutation of P2 also causes a partial skipping of exon 31 with the formation of a premature termination codon in exon 32 in 15% of the total COL6A1 messenger RNA. The remaining two patients carry a heterozygous glycine substitution in exons 9 and 10 inside the triple-helix region; both are dominant mutations because the missense mutations are absent in the DNA of their respective parents. As for the three homozygous recessive mutations, the apparently healthy consanguineous parents all carry a heterozygous mutated allele. Here, for the first time, we report a genotype-phenotype correlation demonstrating that heterozygous glycine substitutions in the triple-helix domain of COL6A1 are dominant and responsible for a milder Ullrich scleroatonic muscular dystrophy phenotype, and that recessive mutations in COL6A1 correlate with more severe clinical and biochemical Ullrich scleroatonic muscular dystrophy phenotypes.
Abstract: OBJECTIVE: Our aim was to assess the respiratory pattern during sleep in patients affected by spinal muscular atrophy types 1 and 2 and to compare their apnea-hypopnea indices with those of controls. DESIGN: All consecutively referred patients underwent polysomnography. Sleep stages were defined as either wake, quiet sleep (QS), or active sleep (AS). As measures of thoracoabdominal coordination, we measured: phase angle during QS and AS (Ph Angle QS and AS), phase relation during inspiration and expiration during QS and AS: (Ph RIB QS, Ph RIB AS, Ph REB QS; Ph REB AS) and the apnea-hypopnea index. RESULTS: The 14 consecutively referred infants and small children (age, 11.7 +/- 11.4 mos) showed a higher apnea-hypopnea index (P < 0.001), Ph Angle QS (P < 0.001), Ph Angle AS (P < 0.001), Ph RIB QS (P < 0.001), Ph RIB AS (P < 0.001), Ph REB QS (P < 0.001), and Ph REB AS (P < 0.001) compared with 28 healthy controls (age, 10.1 +/- 8.9 mos). CONCLUSIONS: Patients affected by types 1 and 2 spinal muscular atrophy had significantly higher apnea-hypopnea indices than controls. Thoracoabdominal asynchrony was present during the inspiratory and expiratory phases in both quiet and active sleep. Measures of thoracoabdominal coordination may be useful for the evaluation and monitoring of therapeutic interventions for these patients.
Abstract: The coexistence of neurogenic and myogenic features in scapuloperoneal syndrome is rarely ascribed to a single gene. Defects in the nuclear envelope protein lamin A/C, encoded by the LMNA gene, have been shown to be associated with a variety of disorders affecting mainly the muscular and adipose tissues and, more recently, with autosomal recessive Charcot-Marie-Tooth type 2 neuropathy. This report is about a patient presenting features of myopathy and neuropathy due to a dominant LMNA mutation, suggesting that the peripheral nerve might be affected in primary LMNA myopathy. Our observations further support the marked intrafamilial and interfamilial phenotypic heterogeneity associated with lamin A/C defects.
Abstract: BACKGROUND: Mutations of oligophrenin 1, one of the first genes identified in nonspecific X-linked mental retardation (MRX), have been described in patients with moderate to severe cognitive impairment and predominant cerebellar hypoplasia, in the vermis. OBJECTIVE: To further delineate the phenotypic and mutational spectrum of the syndrome, by screening oligophrenin 1 in two cohorts of male patients with mental retardation (MR) with or without known posterior fossa anomalies. METHODS: Clinical examination, cognitive testing, MRI studies, and mutational analysis (denaturing gradient gel electrophoresis and direct sequencing) on blood lymphocytes were performed in 213 unrelated affected individuals: 196 patients classified as MRX and 17 patients with MR and previously detected cerebellar anomalies. RESULTS: Four novel oligophrenin 1 mutations were identified. In the MRX group, two nonsense mutations were detected. In the MR group, two mutations were found: a deletion of exons 16 to 17 and a splice site mutation. All patients shared characteristic clinical, radiologic, and distinctive features with a degree of intrafamilial variability in motor and cognitive deficits. CONCLUSIONS: Oligophrenin 1 mutations were found in 12% (2/17) of individuals with mental retardatin and known cerebellar anomalies and in 1% (2/196) of the X-linked mental retardation group.
Abstract: NG2, the rat homologue of the human melanoma chondroitin sulfate proteoglycan (MCSP), is a ligand for collagen VI (COL6). We have examined skeletal muscles of patients affected by Ullrich scleroatonic muscular dystrophy (UCMD), an inherited syndrome caused by COL6 genes mutations. A significant decrease of NG2 immunolabeling was found in UCMD myofibers, as well as in skeletal muscle and cornea of COL6 null-mice. In UCMD muscles, truncated NG2 core protein isoforms were detected. However, real-time RT-PCR analysis revealed marked increase in NG2 mRNA content in UCMD muscle compared to controls. We hypothesize that NG2 immunohistochemical and biochemical behavior may be compromised owing to the absence of its physiological ligand. MCSP/NG2 proteoglycan may be considered an important receptor mediating COL6-sarcolemma interactions, a relationship that is disrupted by the pathogenesis of UCMD muscle.
Abstract: Mutations in the lamin A/C gene (LMNA) have been associated with neuromuscular diseases and more complex syndromes, involving bone and adipose tissue. We report on a case of early onset myopathy due to a heterozygous LMNA mutation in exon 9, characterized by the presence of a marked number of cytoplasmic bodies with extensive myofibrillar abnormalities and Z-disk disruption in skeletal muscle. This case suggests there is a need to increase the list of genes to be screened in patients with myofibrillar myopathy.
Abstract: Danon disease, an X-linked cardioskeletal myopathy caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2), is clinically characterized by cardiomyopathy, myopathy, and variable mental retardation. The pathological hallmark of the disease is the absence of LAMP-2 immunohistochemical staining in muscle. The LAMP-2 gene mutations reported thus far are generally private mutations. We describe two cases of Danon disease with different clinical presentation, in whom we identified the same exon skipping mutation c.928G>A in the LAMP-2 gene. The first patient was affected by an early onset myopathy and hypertrophic cardiomyopathy (HCM) that partially improved with drug treatment. A first muscle biopsy at age 4 months showed markedly increased glycogen, and acid maltase deficiency was ruled out biochemically. A second muscle biopsy, performed at age 3(1/2) years, showed very mild abnormalities. The second child at age 15 years had mild, diffuse muscle weakness and wasting, moderate mental deficiency, and HCM. Two serial biopsies performed at age 8 and 15 years showed similar findings of multiple esterase-positive vacuoles in type I myofibers. In both patients the immunohistochemical study demonstrated the absence of LAMP-2 in skeletal muscle.
Abstract: We report a family with McArdle's disease with several affected individuals in two generations. This unusual pedigree for an autosomal recessive disease is explained by the existence of manifesting heterozygotes in the maternal line. The presence of symptoms in heterozygotes seems to be due to a decrease in myophosphorylase activity below a critical threshold, ranging between 30% and 45% of normal mean value. The occurrence of several manifesting heterozygotes in the maternal line only can be explained by compound heterozygosity of a defective allele and a pseudodeficient allele for myophosphorylase, or by a genetic factor which regulates the phenotypic expression of the gene.
Abstract: Cardiomyopathy was reported in a few Duchenne muscular dystrophy (DMD) carriers with clinical evidence of myopathy. We report two carriers with dilated cardiomyopathy, increased serum CK, and no symptoms of muscle weakness. In heart biopsies of both patients, dystrophin-the protein product of DMD locus--was absent in many fibers. Dilated cardiomyopathy may be the only manifestation of dystrophin gene mutation in carriers.
Abstract: Linkage analysis and prenatal prediction in families segregating autosomal recessive spinal muscular atrophy (SMA) has become feasible since the assignment of the locus responsible for type I-III SMA to region 5q12-q13.3. We have performed a segregation study of SMA in Italian families using molecular probes and highly informative PCR-based polymorphic markers. In one family, a 7-year-old boy affected with type III SMA and an 8-year-old apparently healthy brother had identical haplotypes. These findings prompted us to reexamine the apparently unaffected child. His neurological exam was normal. However, the electromyography (EMG) showed a pattern consistent with chronic SMA. To our knowledge this is the first example of presymptomatic diagnosis of SMA based on genotype analysis.
Abstract: We present a undescribed condition in a girl who died at 8 years of hypertrophic cardiomyopathy. Muscle and endomyocardial biopsies disclosed a selective loss of thick filaments ultrastructurally. In muscle biopsy histochemical abnormalities of myofibrillar AT-Pase were confined to type 1 fibres. Gel electrophoresis of muscle homogenate showed no qualitative abnormalities of slow and fast myosin heavy chains (MHC) and light chains, and the amount of the different myosin isozymes was in agreement with histochemical myofibrillar ATPase findings. The pathogenetic mechanisms have not been elucidated in this case but we suspect an abnormality of the beta-cardiac MHC gene, the only gene expressed in the heart and in type 1 skeletal muscle fibres.
Abstract: We report the intra vitam histopathological findings on the brain of a female patient presenting an adult form of orthochromatic leukodystrophy. At 38 years of age the patient began to show progressive dementia and a pseudobulbar syndrome. The pedigree revealed an autosomal dominant pattern of inheritance. The CT scan showed a wide hypodensity of the anterior white matter. Biochemical investigations showed only a slight elevation of serum VLCFA and no alteration of urinary enzymatic activities. Cortical and subcortical biopsy specimens from the right frontal lobe showed: neuronal loss in the gray matter, accumulation of autofluorescent material within residual neurons and sudanophilic material within macrophages and astrocytes, sparing of axons. Electron microscopy showed lamination and fragmentation of the myelin and the presence of electrondense bodies and vesicular material into oligodendrocytes and astrocytes. We discuss the differential diagnosis of OLD forms with adult onset, namely between Löwenberg-Hill disease and the pure form of OLD with pigmented glial cells.
Abstract: We report on a 5 1/2 year-old boy with chronic progressive polyneuropathy, ataxia, and pyramidal signs. His hair was not curled. Sural nerve biopsy disclosed many axons enlarged by accumulation of 10-nm neurofilaments and a marked variability in the number of myelinated fibers as well as in the amount of axonal enlargements among different fascicles. These findings and the electrophysiological data were consistent with a giant axonal polyneuropathy with a multifocal fiber loss.
Abstract: Two siblings developed a neurological disorder in the first decade characterised by generalised dystonia, hypokinesia, and subacute visual loss. CT and serial MRI examinations showed bilateral lesions of the striatum, mainly in the putamen. The classification of these patients is discussed in relation to infantile bilateral striatal necrosis (IBSN), Leigh's disease, and Leber's optic neuropathy. The literature shows a clinical and aetiopathogenetic overlap between these syndromes. In our cases parental consanguinity and the involvement of a single generation suggest a new clinical condition with autosomal recessive transmission.
Abstract: A 3-month-old girl was admitted to the hospital because of hypotonia and frequent vomiting. She had severe metabolic acidosis and her liver function was abnormal. Hepatomegaly and rapidly progressive liver failure developed, and she died at 4 months of age. Two half-siblings from a different mother had died in infancy of an undiagnosed myopathy. The liver was fatty and hepatocytes were filled with large and small lipid droplets. Other tissues were morphologically normal. The respiratory chain enzymes containing subunits encoded by mitochondrial DNA were markedly decreased in liver, partially decreased in muscle, but normal in other tissues. Southern blot analysis showed 90% depletion of mitochondrial DNA in liver, 53% depletion in muscle, and normal amounts in other tissues. This is the second case of fatal infantile liver failure associated with mitochondrial DNA depletion. This pathogenetic mechanism should be considered in infants with multiple respiratory chain defects and variable tissue expression.
Abstract: An 11-month-old girl presented acute episodes of hypoglycaemia and hepatic encephalopathy reminiscent of Reye syndrome and 3-hydroxydicarboxylic aciduria. The patient showed peculiar clinical manifestations of severe sensory-motor neuropathy, pigmentary retinopathy, and cardiomyopathy. She died of cardiac failure. Pathological studies of peripheral nerve showed signs of axonal neuropathy and demyelination. Enzymatic studies in cultured fibroblasts showed a deficiency of mitochondrial long-chain 3-hydroxyacyl-CoA-dehydrogenase. Peripheral nerve involvement and retinal pigmentary degeneration have as yet not been described in patients with proven defects of mitochondrial beta-oxidation.
Abstract: Neuronal migration anomalies commonly cause seizures that are partial in type and generally refractory to medical treatment. Epilepsia partialis continua (EPC), an unusual form of epilepsy commonly related to acute damage of the cerebral cortex or to a chronic lesion, has never been described in a patient with neuronal migration anomalies. In 50 children with epilepsy due to neuronal migration anomalies, we observed two cases of EPC. These two children had unilateral neuronal migration abnormalities with partial seizures other than EPC and contralateral hemiparesis. Epilepsia partialis continua appeared two to three years after the onset of partial attacks and was accompanied by a worsening of the children's previous hemiparesis. Although a rare seizure manifestation in children with neuronal migration anomalies, when it does appear, EPC can aggravate the clinical neurological condition and should always be investigated for in these cases. Because its clinical appearance is often subtle, as in these two children, EPC may easily remain undiagnosed.
Abstract: A sporadic case (female, aged 14 years) is reported who was affected by myopathy, restrictive cardiomyopathy and sensory motor polyneuropathy. A muscle biopsy showed accumulation of osmiophilic granular and filamentous material on electron microscopy, which stained positively in immunofluorescence for desmin. Increased desmin phosphorylated isoforms have been demonstrated by one- and two-dimensional electrophoresis. Sural nerve biopsy showed a peripheral neuropathy with giant axons, filled with closely packed neurofilaments. Clinical and morphological aspects of this new disease entity are discussed with regards to the classical form of giant axonal neuropathy and to other conditions of peripheral neuropathy with giant axons.
Abstract: We report on 2 boys (maternal cousins), with severe congenital ataxia with generalized hypotonia, psychomotor retardation and recurrent bronchopulmonary infections. Later, they developed myoclonic encephalopathy and macular degeneration. Serial brain imaging investigations showed a cyst of the septum pellucidum, persistence of the cavum vergae, corpus callosum and cerebellar vermis hypoplasia without cortical atrophy. In the maternal pedigree, 5 males had recurrent bronchopneumonia associated with severe congenital hypotonia and died during the first years of life. Neurophysiological studies, including nerve conduction velocities, brainstem auditory evoked responses, somatosensory evoked potentials were normal. Electroretinogram showed normal wave morphology. Visual evoked potentials were mildly impaired. Extensive screening for metabolic disease gave normal results. Immunologic investigations showed normal T and B cell number, T cell function and immunoglobulin levels in both patients with a reduced level of IgG2 subclass in one.
Abstract: We report the biochemical and clinical results obtained during a dietary erucic acid (C22:1) therapy in 20 patients affected by X-linked adrenoleukodystrophy (ALD). Six patients were very severely affected, 9 had milder neurological symptoms and 5 were presymptomatic. Mean basal levels of plasma C26:0 were 1.41 +/- 0.48 micrograms/ml in ALD patients (control values: 0.33 +/- 0.12). In all patients C26:0 decreased to virtually normal values. In spite of good biochemical response and absence of consistent side effects of therapy, no encouraging data were observed during the clinical follow-up. The presymptomatic subjects were still free of symptoms after more than 1 year of therapy. The symptomatic patients, however worsened or did not show any improvement.
Abstract: The clinical, morphological and biochemical findings of a sporadic case, showing accumulation of desmin-type intermediate filaments in skeletal muscle and myocardium are described. Desmin storage was demonstrated by immunofluorescence, sodium dodecyl sulfate gel electrophoresis and two-dimensional gel electrophoresis. These findings are in agreement with those of Rappaport et al. (FEBS lett. 231:421-425, 1989). A sensory-motor polyneuropathy was established by electrophysiological studies and, ultrastructurally, intramuscular nerves showed accumulation of neurofilaments and neurotubules with formation of axonal spheroids. These findings are discussed considering all previous reports with related conditions.
Abstract: We studied a large family with a dominantly inherited mitochondrial myopathy characterized by progressive external ophthalmoplegia, dysphagia, cataract, lactic acidosis, exercise intolerance, and early death. Morphologic studies of muscle biopsies suggested mitochondrial heteroplasmy and revealed ragged-red fibers and decreased histochemical reactions for cytochrome c oxidase and succinate dehydrogenase. Biochemistry showed a partial defect of cytochrome c oxidase and a mild generalized reduction of other mitochondrial enzymes requiring mitochondrial DNA-encoded subunits. Southern blot analysis and PCR amplification showed mitochondrial DNA deletions in muscle of all affected members, but not in lymphocytes or fibroblasts, suggesting a tissue-specific distribution. Deletions were multiple and seemed to increase with time and to correlate with the severity of the disease.
Abstract: A muscle biopsy and autopsy study of a child who died at 14 months of respiratory failure is described. A diagnosis of infantile cytoplasmic body myopathy was made due to the high percentage of cytoplasmic bodies (CBs), particularly in respiratory muscles. No pathological abnormalities were found in the central nervous system, peripheral nerves or visceral organs. Immunohistochemical studies suggested that the central core of CBs was stained for fibrillary actin, being surrounded by a positive signal for desmin. A differential diagnosis as to other conditions involving proliferation of CBs is discussed.
Abstract: Evidence is emerging that primary systemic carnitine deficiency, a potentially lethal but eminently treatable inborn error of fatty acid oxidation, involves a cellular defect in the uptake of carnitine. We present four unrelated children with primary carnitine-responsive cardiomyopathy, weakness (with or without hypoketotic hypoglycemic encephalopathy), low serum and/or tissue carnitine concentrations, and severe renal carnitine leak. Dicarboxylic acids were absent in the urine of three children who were tested, and all four had a rapid and dramatic improvement in cardiac function, strength, and somatic growth after carnitine therapy. We studied carnitine uptake in cultured skin fibroblasts from all four children and seven of the eight healthy nonconsanguinous parents. [3H]L-carnitine uptake was evaluated in vitro under linear time kinetics. Substrate concentrations were varied from 0.1 to 1000 microM. Physiologic uptake was determined at carnitine concentrations between 0.1 and 50 microM. Nonspecific uptake was determined at a concentration of 10 mM. The four patients had negligible uptake throughout the physiologic range, implying a marked deficiency in the specific high-affinity, low-concentration, carrier-mediated uptake mechanism. At a concentration of 5 mumol/L, the mean velocity of uptake in the four patients was 2% of control values. Their parents showed intermediate maximal rates of carnitine uptake ranging from 13 to 44% of control Vmax values, but normal Km values, suggesting that the heterozygotes had a reduced number of normal functioning carnitine transporters. The observed reduction in Vmax values for the parents supports an autosomal recessive inheritance pattern and may be a more sensitive indicator of heterozygosity than serum carnitine concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: A girl affected by a restrictive cardiomyopathy with neuromuscular involvement is described. Morphological examination showed a pattern of multicore myopathy and with electron microscopy a sarcoplasmic accumulation of electron dense granular and filamentous material was demonstrated both in skeletal muscle and heart. This peculiar electron dense material corresponded to increased desmin in muscle and cardiac fibres and was demonstrated immunohistochemically.
Abstract: We determined in normal nonpregnant (group 1) women, normal pregnant (group 2) women, and patients with preeclampsia (group 3) the serum inhibition of platelet-activating factor activity, the presence of detectable amounts of platelet-activating factor in the blood, and platelet responsiveness in vitro to platelet-activating factor, and to other agonists (adenosine diphosphate, collagen, and ristocetin), and prostacyclin (prostaglandin I2). In patients with preeclampsia (group 3) the serum inhibition of platelet-activating factor activity was significantly lower than that in groups 1 and 2. However, no detectable amounts of platelet-activating factor were observed. The mean values of platelet aggregation induced by platelet-activating factor, adenosine diphosphate, collagen and ristocetin, and the prostaglandin I2-inhibitory concentration of 50% which is inversely correlated with platelet sensitivity to prostaglandin I2, were not significantly different between groups 2 and 3. It is suggested that in preeclampsia the defect in serum inhibitory potential of platelet-activating factor--induced platelet aggregation may contribute to the disturbance in the homeostatic balance between proaggregant and antiaggregant substances.
Abstract: Deletions of muscle mitochondrial DNA (mtDNA) have recently been found in patients with mitochondrial myopathy. However, as most of the described cases were sporadic, and individual deletions involved different portions of mtDNA, the mechanism(s) producing the molecular lesions, as well as their mode of transmission, remain unclear. By studying families with mtDNA heteroplasmy, valuable information can be obtained about the role of inheritable factors in the pathogenesis of these disorders. We have studied four members of a family with autosomal dominant mitochondrial myopathy. Multiple deletions, involving the same portion of muscle mtDNA, were identified in all patients. Sequence analysis of the mutant mtDNAs, performed after DNA amplification by the polymerase-chain reaction showed that all the deletions start within a 12-nucleotide stretch at the 5' end of the D-loop region, a site of active communication between the nucleus and the mtDNA. The data indicate that a mutation of a nuclear-coded protein can destroy the integrity of the mitochondrial genome in a specific, heritable way.
Abstract: Smokers' urine was tested for mutagenic activity on Salmonella typhimurium strain TA1538 with metabolic activation after adsorption on different resins and desorption with organic solvents. The amounts of XAD-2 were 1.25 and 5 g/100 ml urine, the amounts of alumina, cyanopropyl and C18 were all 5 g/100 ml and extrelut 80 g/100 ml. Adsorbed organic chemicals were eluted with acetone from XAD-2, with dichloromethane from extrelut and with a series of solvents from the other resins (hexane, toluene, dichloromethane and methanol). All columns gave similar results, with the exception of extrelut, which had poor recovery of mutagenic activity. Higher resin/urine ratios and sequences of columns gave better results. The organic eluates from XAD-2 columns loaded with the urine of patients treated with cyclophosphamide and melphalan were mutagenic on strain TA1535 with S9, and some mutagenic activity was also detectable in the aqueous eluate. Cisplatin was adsorbed on XAD-2, C18 and extrelut, but was eluted only from extrelut using dimethylformamide as a solvent. Smokers' urine was separated into several fractions with high-performance liquid chromatography, using C-18 columns with a series of solutions of 2.5 mM phosphoric acid and acetone or with a gradient of methanol. Several fractions containing dissolved organic compounds and no histidine were mutagenic with metabolic activation, but the overall mutagenic activity was still lower than the one detected with one-step chromatography on XAD-2. Using XAD-2 resins with a high ratio of resin to urine still seems to be the method of choice for studying urinary mutagenicity.
Abstract: We observed 4 children with hemimegalencephaly, (3 boys, 1 girl aged 3-7 years). One child had a linear sebaceous nevus. All patients had a similar clinical, EEG, and neuroradiologic pattern. All patients had macrocrania, hemiparesis, hemianopsia, and psychomotor retardation of variable degree. All cases had an epileptic syndrome with onset during the first days or the first months of life. The seizures were consistently similar: partial motor seizures, generally hemiclonic and asymmetric brief tonic seizures, in series, involving predominantly one side of the body, contralateral to the cerebral damage. The EEG was initially characterized by a hemihypsarrhythmia and afterward, over the malformed hemisphere, by a rather high-frequency background activity associated with almost continuous transients of spikes, sharp waves, and spike and waves that progressively involved the contralateral hemisphere. Hemispherectomy was performed in two children with sudden and complete recovery from seizures and improvement in psychomotor development. Macroscopic examination was consistent with the computed tomography (CT) scan and magnetic resonance imaging (MRI) showing pachygyria and poorly represented white matter. Histologic examination showed the characteristic absence of cortical neuronal layering, and the presence of giant neurons, neuronal heterotopias, and gliosis. For hemispherectomy to be successful, we believe prolonged EEG monitoring is needed to verify that no seizures are originating in the normal hemisphere.
Abstract: We report the clinical, electrophysiological, and morphological observations of five infants with an unusual form of spinal muscular atrophy (SMA). In these infants muscular weakness and atrophy were initially restricted to the distal limbs and this pattern was associated with paralysis of the diaphragm. The difference between the clinical manifestations of this syndrome and the classical form of infantile spinal muscular atrophy (SMA type 1) as well as other congenital hereditary neuropathies is discussed.
Abstract: We report on sibs with scleroatonic familial myopathy (Ullrich disease). Muscular weakness was of relatively late onset in relation to other cases reported in the literature. Short stature and moderate growth hormone deficiency were noted during follow-up. Differential diagnosis with other neuromuscular disorders, particularly rigid spine syndrome, is discussed.
