Abstract: We performed a prospective analysis on 14 11q- patients to determine the relationship between the degree of cognitive impairment and relative deletion size. Seventeen measures of cognitive function were assessed. All nine patients with a deletion of at least 12.1 Mb had severe global cognitive impairment, with full-scale IQ <50, whereas all five patients with smaller deletions, <or=11.8 Mb, demonstrated mild cognitive impairment, with a full-scale IQ of 63 or higher (p < 0.001). Among these five patients, the two patients with the larger deletions (11.4, 11.8 Mb) had a selective impairment in freedom from distractability compared to the three patients with smaller deletions (<or=9.1 Mb). We propose the presence of a proximal critical region that contains a gene for global cognitive function and a distal critical region that contains a gene essential for auditory attention, which may be necessary for optimizing intellectual function. The proximal critical region is 300 kb and contains three annotated genes. One of these genes, BSX, encodes a brain-specific homeobox protein that in gene-targeted mice has been shown previously to have a role in regulating locomotory behavior via BSX-expressing neurons in the hypothalamus. The distal critical region, approximately 2.2 Mb, contains 18 annotated genes. One gene in this region, Neurogranin, has been demonstrated previously in mice to be critical for synapse plasticity and long-term potentiation. Taken together, our results implicate the presence of at least two loci in distal 11q that when deleted, cause global and selective deficits in neurocognitive function. These findings have important implications for genetic counseling and potential gene-specific therapies.
Abstract: Congenital heart defects comprise the most common form of major birth defects, affecting 0.7% of all newborn infants. Jacobsen syndrome (11q-) is a rare chromosomal disorder caused by deletions in distal 11q. We have previously determined that a wide spectrum of the most common congenital heart defects occur in 11q-, including an unprecedented high frequency of hypoplastic left heart syndrome. We identified an approximately 7Mb "cardiac critical region" in distal 11q that contains a putative causative gene(s) for congenital heart disease. In this study, we utilized chromosomal microarray mapping to characterize three patients with 11q- and congenital heart defects that carry interstitial deletions overlapping the 7Mb cardiac critical region. We propose that this 1.2Mb region of overlap harbors a gene(s) that causes at least a subset of the congenital heart defects that occur in 11q-. We demonstrate that one gene in this region, ETS-1 (a member of the ETS family of transcription factors), is expressed in the endocardium and neural crest during early mouse heart development. Gene-targeted deletion of ETS-1 in mice in a C57/B6 background causes, with high penetrance, large membranous ventricular septal defects and a bifid cardiac apex, and less frequently a non apex-forming left ventricle (one of the hallmarks of hypoplastic left heart syndrome). Our results implicate an important role for the ETS-1 transcription factor in mammalian heart development and should provide important insights into some of the most common forms of congenital heart disease.
Abstract: Jacobsen syndrome is a MCA/MR contiguous gene syndrome caused by partial deletion of the long arm of chromosome 11. To date, over 200 cases have been reported. The prevalence has been estimated at 1/100,000 births, with a female/male ratio 2:1. The most common clinical features include pre- and postnatal physical growth retardation, psychomotor retardation, and characteristic facial dysmorphism (skull deformities, hypertelorism, ptosis, coloboma, downslanting palpebral fissures, epicanthal folds, broad nasal bridge, short nose, v-shaped mouth, small ears, low set posteriorly rotated ears). Abnormal platelet function, thrombocytopenia or pancytopenia are usually present at birth. Patients commonly have malformations of the heart, kidney, gastrointestinal tract, genitalia, central nervous system and skeleton. Ocular, hearing, immunological and hormonal problems may be also present. The deletion size ranges from approximately 7 to 20 Mb, with the proximal breakpoint within or telomeric to subband 11q23.3 and the deletion extending usually to the telomere. The deletion is de novo in 85% of reported cases, and in 15% of cases it results from an unbalanced segregation of a familial balanced translocation or from other chromosome rearrangements. In a minority of cases the breakpoint is at the FRA11B fragile site. Diagnosis is based on clinical findings (intellectual deficit, facial dysmorphic features and thrombocytopenia) and confirmed by cytogenetics analysis. Differential diagnoses include Turner and Noonan syndromes, and acquired thrombocytopenia due to sepsis. Prenatal diagnosis of 11q deletion is possible by amniocentesis or chorionic villus sampling and cytogenetic analysis. Management is multi-disciplinary and requires evaluation by general pediatrician, pediatric cardiologist, neurologist, ophthalmologist. Auditory tests, blood tests, endocrine and immunological assessment and follow-up should be offered to all patients. Cardiac malformations can be very severe and require heart surgery in the neonatal period. Newborns with Jacobsen syndrome may have difficulties in feeding and tube feeding may be necessary. Special attention should be devoted due to hematological problems. About 20% of children die during the first two years of life, most commonly related to complications from congenital heart disease, and less commonly from bleeding. For patients who survive the neonatal period and infancy, the life expectancy remains unknown.
Abstract: BACKGROUND AND METHODS: Ring chromosomes are often associated with abnormal phenotypes because of loss of genomic material at one or both ends. In some cases no deletion has been detected and the abnormal phenotype has been attributed to mitotic ring instability. We investigated 33 different ring chromosomes in patients with phenotypic abnormalities by array based comparative genomic hybridisation (CGH) and fluorescence in situ hybridisation (FISH). RESULTS: In seven cases we found not only the expected terminal deletion but also a contiguous duplication. FISH analysis in some of these cases demonstrated that the duplication was inverted. Thus these ring chromosomes derived through a classical inv dup del rearrangement consisting of a deletion and an inverted duplication. DISCUSSION: Inv dup del rearrangements have been reported for several chromosomes, but hardly ever in ring chromosomes. Our findings highlight a new mechanism for the formation of some ring chromosomes and show that inv dup del rearrangements may be stabilised not only through telomere healing and telomere capture but also through circularisation. This type of mechanism must be kept in mind when evaluating possible genotype-phenotype correlations in ring chromosomes since in these cases: (1) the deletion may be larger or smaller than first estimated based on the size of the ring, with a different impact on the phenotype; and (2) the associated duplication will in general cause further phenotypic anomalies and might confuse the genotype-phenotype correlation. Moreover, these findings explain some phenotypic peculiarities which previously were attributed to a wide phenotypic variation or hidden mosaicism related to the instability of the ring.
Abstract: BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients. OBJECTIVE: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients. METHODS: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors. Results and CONCLUSIONS: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.
Abstract: BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients. OBJECTIVE: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients. METHODS: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors. Results and CONCLUSIONS: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.
Abstract: BACKGROUND: Chromosome 13q deletion is associated with varying phenotypes, which seem to depend on the location of the deleted segment. Although various attempts have been made to link the 13q deletion intervals to distinct phenotypes, there is still no acknowledged consensus correlation between the monosomy of distinct 13q regions and specific clinical features. METHODS: 14 Italian patients carrying partial de novo 13q deletions were studied. Molecular-cytogenetic characterisation was carried out by means of array-comparative genomic hybridisation (array-CGH) or fluorescent in situ hybridisation (FISH). RESULTS: Our 14 patients showed mental retardation ranging from profound-severe to moderate-mild: eight had central nervous system (CNS) anomalies, including neural tube defects (NTDs), six had eye abnormalities, nine had facial dysmorphisms and 10 had hand or feet anomalies. The size of the deleted regions varied from 4.2 to 75.7 Mb. CONCLUSION: This study is the first systematic molecular characterisation of de novo 13q deletions, and offers a karyotype-phenotype correlation based on detailed clinical studies and molecular determinations of the deleted regions. Analyses confirm that patients lacking the 13q32 band are the most seriously affected, and critical intervals have been preliminarily assigned for CNS malformations. Dose-sensitive genes proximal to q33.2 may be involved in NTDs. The minimal deletion interval associated with the Dandy-Walker malformation (DWM) was narrowed to the 13q32.2-33.2 region, in which the ZIC2 and ZIC5 genes proposed as underlying various CNS malformations are mapped.
Abstract: Using array comparative genome hybridisation (CGH) 41 de novo reciprocal translocations and 18 de novo complex chromosome rearrangements (CCRs) were screened. All cases had been interpreted as "balanced" by conventional cytogenetics. In all, 27 cases of reciprocal translocations were detected in patients with an abnormal phenotype, and after array CGH analysis, 11 were found to be unbalanced. Thus 40% (11 of 27) of patients with a "chromosomal phenotype" and an apparently balanced translocation were in fact unbalanced, and 18% (5 of 27) of the reciprocal translocations were instead complex rearrangements with >3 breakpoints. Fourteen fetuses with de novo, apparently balanced translocations, all but two with normal ultrasound findings, were also analysed and all were found to be normal using array CGH. Thirteen CCRs were detected in patients with abnormal phenotypes, two in women who had experienced repeated spontaneous abortions and three in fetuses. Sixteen patients were found to have unbalanced mutations, with up to 4 deletions. These results suggest that genome-wide array CGH may be advisable in all carriers of "balanced" CCRs. The parental origin of the deletions was investigated in 5 reciprocal translocations and 11 CCRs; all were found to be paternal. Using customized platforms in seven cases of CCRs, the deletion breakpoints were narrowed down to regions of a few hundred base pairs in length. No susceptibility motifs were associated with the imbalances. These results show that the phenotypic abnormalities of apparently balanced de novo CCRs are mainly due to cryptic deletions and that spermatogenesis is more prone to generate multiple chaotic chromosome imbalances and reciprocal translocations than oogenesis.
Abstract: Background and METHODS: Ring chromosomes are often associated with abnormal phenotypes because of loss of genomic material at one or both ends. In some cases no deletion has been detected and the abnormal phenotype has been attributed to mitotic ring instability. We investigated 33 different ring chromosomes in patients with phenotypic abnormalities by array-CGH (comparative genomic hybridisation) and FISH. RESULTS: In seven cases we found not only the expected terminal deletion but also a contiguous duplication. FISH analysis in some of these cases demonstrated that the duplication was inverted. Thus these ring chromosomes derived through a classical inv dup del rearrangement consisting of a deletion and an inverted duplication. DISCUSSION: Inv dup del rearrangements have been reported for several chromosomes, but hardly ever in ring chromosomes. Our findings highlight a new mechanism for the formation of some ring chromosomes and show that inv dup del rearrangements may be stabilized not only through telomere healing and telomere capture but also through circularization. This type of mechanism must be kept in mind when evaluating possible genotype-phenotype correlations since in these cases (1) the deletion may be larger or smaller than at first estimated based on the size of the ring, with a different impact on the phenotype, and (2) the associated duplication will in general cause further phenotypic anomalies and might confuse the genotype/phenotype correlation. Moreover, these findings explain some phenotypic peculiarities which previously were attributed to a wide phenotypic variation or hidden mosaicism related to the instability of the ring.
Abstract: Using array comparative genome hybridisation (CGH) 41 de novo reciprocal translocations and 18 de novo complex chromosome rearrangements (CCRs) were screened. All cases had been interpreted as "balanced" by conventional cytogenetics. In all, 27 cases of reciprocal translocations were detected in patients with an abnormal phenotype, and after array CGH analysis, 11 were found to be unbalanced. Thus 40% (11 of 27) of patients with a "chromosomal phenotype" and an apparently balanced translocation were in fact unbalanced, and 18% (5 of 27) of the reciprocal translocations were instead complex rearrangements with >3 breakpoints. Fourteen fetuses with de novo, apparently balanced translocations, all but two with normal ultrasound findings, were also analysed and all were found to be normal using array CGH. Thirteen CCRs were detected in patients with abnormal phenotypes, two in women who had experienced repeated spontaneous abortions and three in fetuses. Sixteen patients were found to have unbalanced mutations, with up to 4 deletions. These results suggest that genome-wide array CGH may be advisable in all carriers of "balanced" CCRs. The parental origin of the deletions was investigated in 5 reciprocal translocations and 11 CCRs; all were found to be paternal. Using customized platforms in seven cases of CCRs, the deletion breakpoints were narrowed down to regions of a few hundred base pairs in length. No susceptibility motifs were associated with the imbalances. These results show that the phenotypic abnormalities of apparently balanced de novo CCRs are mainly due to cryptic deletions and that spermatogenesis is more prone to generate multiple chaotic chromosome imbalances and reciprocal translocations than oogenesis.
Abstract: Background and METHODS: Ring chromosomes are often associated with abnormal phenotypes because of loss of genomic material at one or both ends. In some cases no deletion has been detected and the abnormal phenotype has been attributed to mitotic ring instability. We investigated 33 different ring chromosomes in patients with phenotypic abnormalities by array-CGH (comparative genomic hybridisation) and FISH. RESULTS: In seven cases we found not only the expected terminal deletion but also a contiguous duplication. FISH analysis in some of these cases demonstrated that the duplication was inverted. Thus these ring chromosomes derived through a classical inv dup del rearrangement consisting of a deletion and an inverted duplication. DISCUSSION: Inv dup del rearrangements have been reported for several chromosomes, but hardly ever in ring chromosomes. Our findings highlight a new mechanism for the formation of some ring chromosomes and show that inv dup del rearrangements may be stabilized not only through telomere healing and telomere capture but also through circularization. This type of mechanism must be kept in mind when evaluating possible genotype-phenotype correlations since in these cases (1) the deletion may be larger or smaller than at first estimated based on the size of the ring, with a different impact on the phenotype, and (2) the associated duplication will in general cause further phenotypic anomalies and might confuse the genotype/phenotype correlation. Moreover, these findings explain some phenotypic peculiarities which previously were attributed to a wide phenotypic variation or hidden mosaicism related to the instability of the ring.
Abstract: Molecular definition at the BAC level of an 8p dicentric chromosome and an 8p deleted chromosome is reported in a patient with two different cell lines. The dicentric, which differed from that generating the recurrent inv dup del(8p) for the location of its break point, originated during the paternal meiosis on the background of the classical 8p23.1 inversion polymorphism. The breakage of this dicentric gave rise to the 8p deleted chromosome which, as a result of the inversion, had two non-contiguous deletions. These findings confirm previous data on 1p distal deletions, showing that at least some of the deletions stem from the breakage of dicentric chromosomes. They suggest that non-contiguous deletions may be frequent among distal deletions. This type of rearrangement can easily be overlooked when two contiguous clones, one absent and the other present by FISH analysis, are taken as boundaries of the deletion break point; in this case only high resolution array-CGH will reveal their real frequency. The definition of such non-contiguous distal deletions is relevant for phenotype/karyotype correlations. There are historical examples of blunders caused by overlooking a second non-contiguous deletion. This paper shows how small scale structural variations, such as common polymorphic inversions, may cause complex rearrangements such as terminal deletions.
Abstract: Molecular definition at the BAC level of an 8p dicentric chromosome and an 8p deleted chromosome is reported in a patient with two different cell lines. The dicentric, which differed from that generating the recurrent inv dup del(8p) for the location of its break point, originated during the paternal meiosis on the background of the classical 8p23.1 inversion polymorphism. The breakage of this dicentric gave rise to the 8p deleted chromosome which, as a result of the inversion, had two non-contiguous deletions. These findings confirm previous data on 1p distal deletions, showing that at least some of the deletions stem from the breakage of dicentric chromosomes. They suggest that non-contiguous deletions may be frequent among distal deletions. This type of rearrangement can easily be overlooked when two contiguous clones, one absent and the other present by FISH analysis, are taken as boundaries of the deletion break point; in this case only high resolution array-CGH will reveal their real frequency. The definition of such non-contiguous distal deletions is relevant for phenotype/karyotype correlations. There are historical examples of blunders caused by overlooking a second non-contiguous deletion. This paper shows how small scale structural variations, such as common polymorphic inversions, may cause complex rearrangements such as terminal deletions.
Abstract: Interstitial deletions of chromosome 15q, not involving the PWS/AS region, are uncommon and poorly characterized. Few cases defined at the cytogenetic level have been reported with 15q21 deletions and characteristic facial dysmorphisms are present in all them. We report on the molecular characterization by array-CGH of a new patient with a 15q21 deletion and on the redefinition of a second patient previously studied with multicolor banding. The two deletions resulted to be similar and involve about 12 and 8 Mb, respectively. Our study might promote to delineate a better genotype-phenotype correlation associated with 15q21 deletions.
Abstract: INTRODUCTION: Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis, resulting from deficient 7-dehydrocholesterol reductase (3beta-hydroxysterol Delta7-reductase) activity, the enzyme responsible for conversion of 7-dehydrocholesterol to cholesterol. SLOS is most common among people of European descent, with a reported incidence of 1 per 20,000-60,000 newborns, depending on the diagnostic criteria and the reference population. More than 80 different mutations have been identified in several hundred patients. In Italy, SLOS appears to be a rare condition, probably because of underdiagnosis. METHOD: We analyzed by direct sequencing the 7-dehydrocholesterol reductase gene (DHCR7) in a Sicilian patient with Smith-Lemli-Opitz syndrome and his parents in order to characterize the molecular defect. RESULTS: The molecular analysis of the coding exons and the intron-exon boundaries of the DHCR7 gene demonstrated the presence of two missense mutations: a novel mutation (I251N) and a known mutation (E288K) responsible in a compound heterozygous state for a severe form of SLOS. CONCLUSION: The present study describes a Sicilian patient, a carrier of a novel mutation of the DHCR7 gene (I251N), which is responsible in a compound heterozygous state for a severe form of SLOS.
Abstract: DiGeorge and Velocardiofacial syndromes (DGS/VCFS) are endowed by a similar complex phenotype including cardiovascular, craniofacial, and thymic malformations, and are associated with heterozygous deletions of 22q11 chromosomal band. The Typically Deleted Region in the 22q11.21 subband (here called TDR22) is very gene-dense, and the extent of the deletion has been defined precisely in several studies. However, to date there is no evidence for a mechanism of haploinsufficiency that can fully explain the DGS/VCFS phenotype. In this study, we show that the candidate gene HIRA/Tuple1 mapping on the non-deleted TDR22, in DGS/VCFS subjects presents a delayed replication timing. Moreover, we observed an increase in the cell ratio showing the HIRA/Tuple1 locus localised toward the nuclear periphery. It is known that replication timing and nuclear location are generally correlated to the transcription activity of the relative DNA region. We propose that the alteration in the replication/nuclear location pattern of the non-deleted TDR22 indicates an altered gene regulation hence an altered transcritpion in DGS/VCFS.
Abstract: We performed a prospective study of 110 patients (75 not previously published) with the 11q terminal deletion disorder (previously called Jacobsen syndrome), diagnosed by karyotype. All the patients have multiple dysmorphic features. Nearly all the patients (94%) have Paris-Trousseau syndrome characterized by thrombocytopenia and platelet dysfunction. In total, 56% of the patients have serious congenital heart defects. Cognitive function ranged from normal intelligence to moderate mental retardation. Nearly half of the patients have mild mental retardation with a characteristic neuropsychiatric profile demonstrating near normal receptive language ability, but mild to moderate impairment in expressive language. Ophthalmologic, gastrointestinal, and genitourinary problems were common, as were gross and fine motor delays. Infections of the upper respiratory system were common, but no life-threatening infections were reported. We include a molecular analysis of the deletion breakpoints in 65 patients, from which genetic "critical regions" for 14 clinical phenotypes are defined, as well as for the neuropsychiatric profiles. Based on these findings, we provide a comprehensive set of recommendations for the clinical management of patients with the 11q terminal deletion disorder.
Abstract: A 2-year-old girl presented with severe global developmental delay weakness, and an elevated serum creatine kinase level. Her muscle biopsy was consistent with an active dystrophy with absence of dystrophin in about half of the muscle fibers. Fluorescent in situ hybridization analysis showed her karyotype to be 46, X, delX p23.1-p21.1. This large deletion includes the dystrophin gene as well as the region involved in X-linked mental retardation. The genetic mechanism for the manifestation of both diseases is likely non-random inactivation of the X chromosome. To our knowledge, the combination of this dystrophinopathy in association with severe mental retardation has not been described in a girl.
Abstract: Familial adenomatous polyposis (FAP) is a common hereditary syndrome characterized by early development of colorectal cancer consequent to extensive adenomatous polyps of the colon. In addition to the colonic manifestations the syndrome presents several extracolonic features including polyps of the upper gastrointestinal tract, congenital hypertrophy of the retinal pigment, jaw cysts, osteomata and desmoid tumors. In this study the entire APC coding region has been analysed for mutation in a panel of one Turcot and 33 unrelated Italian FAP patients using SSCP analysis, PTT and DNA sequencing. We detected APC mutations in 23 of them and identified nine which, to our knowledge were not previously reported. All of these novel mutations are in exon 15, including two nonsense mutations, 6 deletions or insertions leading to premature termination of the protein and one missense mutation (7697G>A). This last mutation occurs in the EB1-binding domain of the APC protein and segregates in four relatives of the patient with three of them presenting 2-3 adenomatous polyps.
Abstract: Down's syndrome (DS) is associated with several defects of both specific and non-specific immunity which may explain the enhanced susceptibility of DS subjects to viral and bacterial infections. In this study we have evaluated the effects of the new synthetic immunomodulator pidotimod in recurrent infections of the upper respiratory tract in a group of children with DS. It was an open trial vs untreated control, the pidotimod-treated group consisted of 14 subjects and the control group of 12. Pidotimod was administered at the dose of one 400 mg oral bottle/day for 90 days. There was a significant reduction in the frequency, severity and duration of infectious episodes in the pidotimod-treated group vs the untreated control group. The beneficial effects of pidotimod were also confirmed by a series of recordings made over the 90-day treatment period which showed a significant reduction in the number of days of fever, severity of the signs and symptoms of the acute episodes and use of antibiotics and antipyretic drugs. Pidotimod was well tolerated and no clinical, hematological or biochemical side-effects were noted.
Abstract: We describe a patient with double trisomy 9q34.1-->qter and 21pter-->q22.1 resulting from 3:1 segregation of a maternal balanced translocation. The patient shows a clinical syndrome similar to that observed in patients with duplication of the chromosome 9q distal region, while no signs of trisomy 21 were observed. The use of high resolution banding and FISH were of fundamental importance for the cytogenetic diagnosis and for definition of the breakpoints on both chromosomes 9 and 21.
Abstract: We describe a patient with double trisomy 9q34.1-->qter and 21pter-->q22.1 resulting from 3:1 segregation of a maternal balanced translocation. The patient shows a clinical syndrome similar to that observed in patients with duplication of the chromosome 9q distal region, while no signs of trisomy 21 were observed. The use of high resolution banding and FISH were of fundamental importance for the cytogenetic diagnosis and for definition of the breakpoints on both chromosomes 9 and 21.
Abstract: Thrombocytopenia or pancytopenia is frequently reported in patients with partial 11q deletion but there are no reports on bone marrow morphology of these patients. We report on a patient with partial deletion of the long arm of chromosome 11 [del(11)(q24.2qter)] and its classical clinical manifestations including chronic thrombocytopenic purpura in whom micromegakaryocytes were found in the bone marrow aspirate. This is the first report of the presence of micromegakaryocytes in the bone marrow of a patient with 11q deletion. Accurate examination of the bone marrow of other patients with the 11q deletion may clarify whether the observation of micromegakaryocytes is common in these patients. Micromegakaryocytes may indicate a defect of development. Two genes for two DNA binding proteins that are likely to be involved in hematopoiesis map in the 11q region: Ets-1, that maps to 11q24, close to D11S912, and the nuclear-factor-related-kB gene that maps to 11q24-q25. It is possible that these genes, when present in only one copy, result in thrombocytopenia or pancytopenia as observed in this patient.
Abstract: We evaluated the reactogenicity and immunogenicity of an acellular pertussis vaccine in 24 subjects affected by Down's syndrome and in 10 normal infants. Neither general nor local adverse reactions were observed in either group of subjects. The new acellular vaccine administration elicited protective levels of antibodies in all the subjects with Down's syndrome, although the geometric mean titres of IgG antibodies against Bordetella pertussis in these subjects were significantly lower than in normal controls.
Abstract: Jacobsen syndrome is caused by segmental aneusomy for the distal end of the long arm of chromosome 11. Typical features include mild to moderate psychomotor retardation, trigonocephaly, facial dysmorphism, cardiac defects, and thrombocytopenia, though none of these features are invariably present. To define the critical regions responsible for these abnormalities, we studied 17 individuals with de novo terminal deletions of 11q. The patients were characterized in a loss-of-heterozygosity analysis using polymorphic dinucleotide repeats. The breakpoints in the complete two-generation families were localized with an average resolution of 3.9 cM. Eight patients with the largest deletions extending from 11q23.3 to 11qter have breakpoints, between D11S924 and D11S1341. This cytogenetic region accounts for the majority of 11q- patients and may be related to the FRA11B fragile site in 11q23.3. One patient with a small terminal deletion distal to D11S1351 had facial dysmorphism, cardiac defects, and thrombocytopenia, suggesting that the genes responsible for these features may lie distal to D11S1351. Twelve of 15 patients with deletion breakpoints as far distal as D11S1345 had trigonocephaly, while patients with deletions distal to D11S912 did not, suggesting that, if hemizygosity for a single gene is responsible for this dysmorphic feature, the gene may lie distal to D11S1345 and proximal to D11S912.
Abstract: The fragile site FRA11B has been localized to the p(CCG)n repeat of the CBL2 proto-oncogene. A proportion of Jacobsen (11q-) syndrome patients inherited a chromosome carrying a CBL2 p(CCG)n expansion, which was truncated close to FRA11B. These results have broad implications for the role of p(CCG)n repeat expansion in the aetiology of genetic disease involving chromosome rearrangements.
Abstract: A female patient with Down syndrome due to unbalanced Robertsonian translocation (14;21) is reported. A different Robertsonian translocation involving a chromosome no. 14 was observed in her father, who was a carrier of a balanced Robertsonian t(13;14), while the maternal karyotype was normal. Hypotheses about the origin of the translocation in the daughter are discussed.
Abstract: A family with inv8(p23q22), in which one girl with a derivative chromosome 8 showed the characteristic phenotype, is reported. Our case differs from the 32 known families with inv8(p23q22), being the first of apparently non-Hispanic descent. The anomaly may, however, have its origins in the Spanish domination of Sicily.
Abstract: A Sicilian family with three siblings affected by Wolfram's syndrome (Ws) is reported. HLA typing was performed in eight individuals from this family through three generations. Two of the three patients were HLA DR2 positive. The results suggest that the gene for Ws is not linked to the HLA region on chromosome 6, but located on some other chromosome, and that the allele HLA DR2 might predispose to the mutation responsible for Ws.
Abstract: We have studied a group of 349 institutionalized propositi with mental retardation, and found 12 fra(X)-positive cases among 155 males (7.7%) and 8 fra(X)-positive cases among 194 females (4.1%). The males had characteristic manifestations of the Martin-Bell syndrome. Another 7 males, who were initially considered "borderline", having expression of fra(X) less than 4% and a non-characteristic phenotype, were eventually considered negative. Among 5,624 patients (2,764 males and 2,860 females) that were admitted to the Pediatric Department of the University of Catania during the period July 1986 - June 1987, 210 (120 males and 90 females) had mental retardation. Of these, 75 were analyzed for the presence of fra(X) (q27.3); 5 males (0.18% of all males) and 2 females (0.07% of all females) were fra(X)-positive. The males had the Martin Bell syndrome phenotype. The presence of fra(X) (q27) was confirmed in another 4 male propositi that were referred to our outpatient services with a clinical diagnosis of Martin-Bell syndrome.
Abstract: A case of trisomy 9p syndrome is reported. The karyotype showed a tandem duplication of the short arm and of the inverted heterochromatic block of chromosome 9. Unequal sister chromatid exchange seems to be the only possible cause of this finding.
Abstract: A 10-year-old girl with cytological and immunological characteristics of B-cell acute lymphoblastic leukemia is reported. Chromosomal analysis revealed the presence of t(8;14) and i(7q).
Abstract: The authors describe a pair of twins, one of whom showed acardia while the other had severe neural tube defect including anencephaly. This is the first observation of a fetal malformation (anencephaly) in the cotwin of an acardius and confirms the fact that even the cotwin of an acardiac fetus may be at risk of severe congenital malformations.
Abstract: A malformed male infant with pure partial trisomy 12q (q24.1 leads to qter), resulting from an unbalanced segregation of a paternal balanced translocation t(2;12)(q37;q24.1), is described. The cytogenetic and clinical abnormalities of the proband are compared with those of four previously reported cases of partial trisomy 12q, two of which also appear to have pure trisomy of segment 12q24.1 leads to 12 qter.
Abstract: 28 of 1002 pregnant Sicilian women (2.8%) were asymptomatic HBsAg chronic carriers. 18 children of these women were followed and at least 15 of them showed evidence of transplacental infection with HBsAg, resulting either from the presence of the antigen in cord blood, or from the development of the corresponding antibody in the serum within the first 2 months of life. Despite this, only 2 or 3 of the infants developed chronic antigenaemia from age 2--4 months. Only the infants whose mothers were HBeAb-negative, and who themselves remained HBsAb-negative during the first months of life, became HBsAg carriers. On the basis of these results, a strategy is suggested for selecting infants from areas with a high prevalence of HBsAg carriers so that they can be given passive immunisation with hyperimmune globulin.
