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GM1-gangliosidosis and Morquio B disease are rare lysosomal storage disorders caused by beta-galactosidase deficiency due to mutations in the GLB1 gene. Three major clinical forms of GM1-gangliosidosis have been established on the basis of age of onset and severity of symptoms: infantile, late infantile/juvenile, and adult. We performed mutation analysis on 30 GM1-gangliosidosis and five Morquio B patients, mainly of Spanish origin, and all the causative mutations were identified. Thirty different mutations were found, 21 of which were novel. With the exception of two adults and one juvenile patient, all the GM1-gangliosidosis patients were affected by the infantile form. Clinical findings are presented for all patients. We report the association of the novel mutations p.T420K and p.L264S with the adult form and the juvenile form, respectively. In addition, the novel mutation p.Y83C was associated with Morquio B disease. Among the 30 GM1-gangliosidosis patients, 6 were of Gypsy origin (Roma). Moreover, those six Gypsy patients shared not only the same mutation (p.R59H) but also a common haplotype. This observation indicates a possible founder effect in this group and suggests that screening of the p.R59H mutation may be appropriate in GM1-gangliosidosis patients of Gypsy origin. This is the first exhaustive mutational analysis performed in a large group of Iberian GM1-gangliosidosis and Morquio B patients.

Type 1 Gaucher disease (GD), a non-neuronopathic lysosomal storage disorder, results from the deficient activity of acid beta-glucosidase (GBA). Type 1 disease is panethnic but is more prevalent in individuals of Ashkenazi Jewish (AJ) descent. Of the causative GBA mutations, N370S is particularly frequent in the AJ population, (q approximately .03), whereas the 84GG insertion (q approximately .003) occurs exclusively in the Ashkenazim. To investigate the genetic history of these mutations in the AJ population, short tandem repeat (STR) markers were used to map a 9.3-cM region containing the GBA locus and to genotype 261 AJ N370S chromosomes, 60 European non-Jewish N370S chromosomes, and 62 AJ 84GG chromosomes. A highly conserved haplotype at four markers flanking GBA (PKLR, D1S1595, D1S2721, and D1S2777) was observed on both the AJ chromosomes and the non-Jewish N370S chromosomes, suggesting the occurrence of a founder common to both populations. Of note, the presence of different divergent haplotypes suggested the occurrence of de novo, recurrent N370S mutations. In contrast, a different conserved haplotype at these markers was identified on the 84GG chromosomes, which was unique to the AJ population. On the basis of the linkage disequilibrium (LD) delta values, the non-Jewish European N370S chromosomes had greater haplotype diversity and less LD at the markers flanking the conserved haplotype than did the AJ N370S chromosomes. This finding is consistent with the presence of the N370S mutation in the non-Jewish European population prior to the founding of the AJ population. Coalescence analyses for the N370S and 84GG mutations estimated similar coalescence times, of 48 and 55.5 generations ago, respectively. The results of these studies are consistent with a significant bottleneck occurring in the AJ population during the first millennium, when the population became established in Europe.

ABSTRACT:The major elements of bone pathology in Gaucher disease are a failure of osteoclast and osteoblast function, resulting in osteopenia and also osteonecrosis. T lymphocytes have recently been found to be involved in the regulation of osteoblast/osteoclast activity in vitro. In the present report the peripheral blood T major lymphocyte subsets were investigated in a group of genotyped type 1 Gaucher disease patients. A total of 31 patients were studied: 21 non-splenectomized (5 N370S homozygotes) and 10 splenectomized (of whom 1 was a N370S homozygote). The results show that non-splenectomized patients present a decrease in absolute numbers of peripheral blood T lymphocytes, specially the CD4 ϩ T subset. However, when patients were analyzed with respect to the presence of bone disease, the number of CD8 ϩ T lymphocytes was found to be statistically significantly lower in patients presenting bone involvement. Furthermore, lower numbers of CD8 ϩ T lymphocytes were significantly correlated with higher levels of plasma tartrate resistant acid phosphatase (TRAP) activity, a putative marker of osteoclast cell activity. These in vivo findings are in agreement with the results reached in vitro by others.

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