Abstract: Type 1 Gaucher disease (GD1) is characterized by the lack of central nervous system involvement, however, there are several reports of associated neurological manifestations. The aim of this study was to systematically evaluate neurological manifestations in thirty-one GD1 patients (12 males/19 females), mean age 39.4 (range 5-77) years. Participants underwent a complete neurological examination and cognitive tests. Investigation about symptoms and medication intake and motor and sensory electroneurograms were obtained. 30.7% of adult patients had neurological deficits including psychomotor delay, parkinsonism, dementia, impaired saccadic ocular movements, and peripheral nerve dysfunction. Three of them were redefined as type 3 GD. Electrodiagnosis was performed on 15 patients, 26.7% of them had reduced amplitude and/or abnormal wave forms in at least three nerves, 33.3% had a mild reduction in amplitude of two nerves, and 40% had amplitude reduction in one nerve. Patients with three or more affected nerves had additional neurological symptoms. Our results demonstrate that neurological alterations occur in patients diagnosed with GD1, and subclinical peripheral neuropathy is a frequent finding.

Abstract: Semi quantitative MRI is a very useful procedure for evaluating the bone marrow burden (BMB) in Gaucher disease (GD). Score systems have been applied to obtain a parameter for evaluating the severity of bone disease. Our purpose was to test a simple, reproducible and accurate score to evaluate bone marrow involvement in GD patients. MRI was performed in spine, pelvis and femora at diagnosis in 54 adult GD1 patients, 61.1% of whom were female. Three MRI patterns and punctuation in each location were defined: normal, 0; non-homogeneous infiltration subtypes reticular, 1; mottled, 2; diffuse, 3; and homogeneous infiltration, 4. This score was called Spanish-MRI (S-MRI). Two independent observers applied the S-MRI and bone marrow burden score and compared the differences using the non-parametric Mann-Whitney test. Correlation rank test was calculated. In 46 patients (85.2%), bone involvement was observed. Thirty-nine (72.3%) had their spine affected, 35 (64.8%) pelvis and 33 (61.2%) femora. Fourteen patients had bone infarcts, 14 avascular necrosis, 2 vertebral fractures and 2 bone crises. Correlation analysis between S-MRI and BMB was (r(2)=.675; p=.0001). No evidence of correlation was observed between CT activity and S-MRI nor between CT activity and BMB. We have found a relationship between genotype and bone infiltration according to S-MRI site and complications. S-MRI is a simple method that provides useful information to evaluate bone infiltration and detect silent complications. Our results correlated with the BMB score but offer higher sensitivity, specificity and accuracy for classifying the extent of bone disease.

Abstract: Mutations in the glucocerebrosidase (GBA) gene cause Gaucher disease (GD). The aim of this study was to characterise the GBA mutations and analyze genotype/phenotype relationships in 193 unrelated patients from the Spanish GD Registry. We have identified 98.7% of the mutated GBA alleles, finding 56 different GBA mutations and 66 genotypes causing GD in Spain: 47 previously described mutations and 9 novel mutations (4 missense R395C, R463H, W312R and V398I, 1 nonsense R359X, 4 frameshift c.708delC, c.1214-1215delGC, c.1439-1445del7 and c.42-65del24). The most prevalent mutations were N370S and L444P, accounting for 68.7% of the mutated alleles. A wide phenotypic difference was observed within each genotypic group, and 9% of diagnosed type 1 patients developed neurological involvement including parkisonism, tremor, hypoacusia and eye movements. All of these findings indicate that there is a significant genotypic heterogeneity that explains the huge phenotypic variation among Spanish GD patients.

Abstract: PURPOSE: Gaucher disease (GD) is an autosomal recessive lysosomal disorder caused by a deficiency of glucocerebrosidase. The neurologic manifestations of GD patients have to date been refractory to any treatment approach. We present a report of a neuronopathic GD patient whose myoclonic epilepsy improved after combination therapy with imiglucerase and miglustat. METHODS: In an adult type 3 GD patient who, despite good visceral and analytic response to ERT, developed progressive neurologic deterioration with marked myoclonic epilepsy and dystonia, we added miglustat to the enzyme-replacement therapy. RESULTS: After 2 years of combined miglustat (200 mg, 3 t.i.d.) and imiglucerase (60 IU/kg every 2 weeks), generalized tonic-clonic seizures decreased, speech improved, and the general neurologic clinical picture improved markedly. The EEG showed a reduction in focal and generalized paroxysmal discharges. No significant adverse effects were observed. CONCLUSIONS: Combined imiglucerase and miglustat therapy may be beneficial for some neuronopathic forms of GD.

Abstract: In a prospective, open-label study, 25 patients with mild-to-moderate type 1 Gaucher's disease (GD1) were treated with miglustat (Zavesca), an oral glucosylceramide synthase inhibitor, over 12 months. Of the 25 patients, 10 were therapy-naïve and 15 had previously received enzyme replacement therapy (ERT). Clinical status, blood parameters, biomarkers, and organomegaly were assessed at baseline at 6 months and at 12 months. At 6 months the previously untreated patients showed a mean increase in hemoglobin of 0.77 g/dL, platelet counts improved or remaining stable, chitotriosidase and CCL18 decreased. These results were similar to those observed in 40 Spanish GD1 patients on ERT. Bone marrow infiltration cleared at 12 months. In the previously treated group, clinical and hematologic parameters and biomarkers were maintained/ improved at 12 months. Miglustat was well tolerated. The efficacy of miglustat treatment after 6 months was comparable to that of ERT.

Abstract: Chitotriosidase protein (ChT) is the most important biochemical marker described for Gaucher disease (GD). ChT activity is increased several hundred-fold in plasma of GD patients and shows a strong positive correlation with the severity of the disease. However, a recessively inherited enzyme deficiency, with an incidence of about 6% in the Caucasian population, means that not all patients with GD can be monitored by measuring ChT activity. Applying two-dimensional gel electrophoresis (2-DE) technology this study describes the localization and identification of five ChT isoforms in 2-DE images obtained from plasma of GD patients. All these isoforms were unequivocally identified using MALDI-TOF mass spectrometry (MS) and validated by western blot analysis. The features of each ChT isoform separated by 2-DE in plasma from GD patients homozygous for the wild-type ChT allele, carriers of one defective allele and patients homozygous for the mutant allele are presented. We also show the correlation between each ChT isoform and the plasma ChT enzymatic activity of the GD patients sampled in this study.

Abstract: Gaucher disease (GD) is a disorder of glycosphinglipid metabolism caused by deficiency of lysosomal acid beta-glucosidase (GC), resulting in progressive deposition of glucosylceramide in macrophages. The glucose analogue, N-butyl-deoxynojirimycin (NB-DNJ, Miglustat), is an inhibitor of the ceramide-specific glucosyltransferase (CSG) which catalyzes the first step of glycosphingolipids biosynthesis and is currently approved for the oral treatment of type 1 GD. Using site-directed mutagenesis, we constructed plasmids containing wild-type and several mutations in glucocerebrosidase (GBA) gene. The plasmids were transfected into COS-7 cells and stable transfected cell lines were obtained by geneticin (G418) selection. Cells were cultured during 6 days with medium with or without 10 microM NB-DNJ. The addition of NB-DNJ to COS-7 cell medium leads to 1.3-, 2.1-, 2.3-, 3.6-, and 9.9-fold increase in the activity of S364R, wild-type, N370S, V15M, and M123T GC, respectively. However, no significant changes were observed in the activity of the L444P, L336P, and S465del mutated proteins, but a small decrease in the rare P266L variant was observed. These results suggest that NB-DNJ, in addition to the inhibitory effect on CSG, also works as a "chemical chaperone", increasing the activity of acid beta-glucosidase of wild-type and several GC mutated proteins, including the most frequent N370S mutation. The specific location of the Miglustat binding site in GC is unknown. Potential binding sites in the enzyme have been searched for using computational molecular docking. The searching strategy identified three potential GC binding sites for Miglustat, one being the substrate-binding site of the enzyme, which was the best-ranked site by AutoDock program. Therefore, it is possible that Miglustat exerts its chaperoning activity on acid beta-glucosidase by acting as an inhibitor bound at the active site. This increase on the activity of the acid beta-glucosidase would imply that Miglustat is not only a substrate reducer but also an inhibitor of the GC degradation, with very promising clinical implications for the treatment of GD patients.

Abstract: BACKGROUND: Gaucher disease (GD) is a heterogeneous disease characterized by an impaired activity of the lysosomal glucocerebrosidase. This heterogeneity is attributed in part to the existence of a large number of mutations in the corresponding gene. SUBJECTS AND METHODS: To establish genotype-phenotype relationships, we analyzed the residual enzyme activities of six naturally occurring mutations found in Spanish population in the glucocerebrosidase gene [c.160G > A (V15M), c.485T>C (M123T), c.914C>T (P266L), c.1124T>C (L336P), c.1207A>C (S364R) and c.1510-1512delTCT (S465del)]. The mutated genes were subcloned into the mammalian expression vector pCR 3.1 and expressed by transient transfection in COS cells. The enzymatic activity of the expressed protein were measured and compared with the wild-type human glucocerebrosidase cDNA. Also, two previously alleles, c.1226A>G (N370S) and c.1448T>C (L444P), were used for comparative purposes. RESULTS: The residual activity of the expressed proteins using the synthetic substrate (4-methylumbelliferyl-beta-D-glucopyranoside, 4MU-Glu) ranged from 5.5% (for the 3-bp deletion) to 42.7% (for S364R mutation) of the activity of the wild-type enzyme. CONCLUSION: The present analyses may help to better understand the molecular basis and the pathogenesis of Gaucher disease. However, results of expression of mutated enzymes are necessary but not sufficient to explain the ultimate clinical outcome of Gaucher disease.

Abstract: BACKGROUND AND OBJECTIVE: Gaucher's disease (GD) is a lysosomal storage disorder, caused by a deficiency of the acid -glucocerebrosidase enzyme, which results in accumulation of lipids within macrophages. GD patients show decreased plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) levels, as well as decreased apolipoprotein (apo) A-I and B. Conversely, concentrations of plasma apo E and the chitotriosidase (ChT) activity, a chitinase synthesized by activated macrophages, are increased. Enzyme replacement therapy (ERT) is effective and safe in reversing the clinical manifestations in symptomatic patients. The aim of this study was to evaluate the effect of ERT on the lipid profile of GD patients. PATIENTS AND METHOD: 70 patients, from the Spanish Registry of Gaucher's disease (REEG), were divided into two groups: 54 under ERT, according to stablished criteria, and 16 without ERT.Plasma apolipoprotein, lipoprotein and lipid concentrations, and chitotriosidase activity were analyzed in both groups. Statistical analysis was carried out with the U-Mann Whitney non-parametric test for comparison of data. RESULTS: The group of GD patients under ERT showed significant increases of HDL-c (+38%) and apo A-I (+18%) levels, whereas no changes were observed in LDL-c and apo B levels. Conversely, chitotriosidase activity (-58%), plasma-apo E (-32%) and HDL-apo E (-26%) levels were dramatically reduced after ERT. No significant modifications were observed in the group without ERT. CONCLUSIONS: ERT in GD patients displays significant effects on the concentration of plasma lipoproteins, resulting in a less atherogenic lipid profile and in a reduction of activated macrophages.

Abstract: Gaucher disease (GD) is the most frequent lysosomal storage disease, caused by mutations in the acid beta-glucosidase gene (GBA). The c.1226A > G (N370S) mutation is associated with non-neuronopathic disease (type 1). However, we have observed some discrepancy between genotype and phenotype in Spanish Gaucher disease patients homozygous for the c.1226A > G mutation. A deletion of 55 bp in the exon 9 GBA gene, corresponding to the deleted portion of the beta-glucosidase pseudogene, has been previously reported as a cause of erroneous assignment of 1226G/1226G homozygous patients when the genotype has been performed by PCR assay. We had originally identified 25 (out of 124) unrelated Gaucher disease patients as being putative homozygotes for the c.1226A > G mutation. By means of a new PCR-based assay, we were able to distinguish between the true homozygous patients and the carriers of the 55-bp deletion in exon 9 of the GBA gene. The 55-bp deletion was detected in 10 out of 25 samples (40%) [7 with the 55-bp deletion, 1 RecTL, 1 RecNciI (both including the deletion) and one rearrangement]. Such a high prevalence in this sample suggests that this allele can be more common than expected among GD patients.