The adult form of Tay-Sachs disease, adult GM2 gangliosidosis, is an autosomal recessive neurological disorder caused by a partial deficiency of β-hexosaminidase A. We had previously identified, in Ashkenazi-Jewish adult GM2 gangliosidosis patients, a Gly269→Ser mutation in the β-hexosaminidase α-subunit. All of the Ashkenazi patients were found to be compound heterozygotes with an allele containing the Gly269→Ser mutation together with one of the Ashkenazi infantile Tay-Sachs alleles. We have now found the same Gly269→Ser mutation in six adult GM2 gangliosidosis patients from four different non-Jewish families. Genomic DNA from three of the patients, two of whom were brothers, exhibited a hybridization pattern consistent with homozygosity for the Gly269→Ser mutation. The remaining non-Jewish patients were compound heterozygotes of the Gly269→Ser mutation together with an unidentified α-subunit mutation. The results demonstrate that individuals homozygous for the Gly269→Ser change can be clinically affected. The same Gly269→Ser mutation in both the Ashkenazi and non-Jewish patients may be the result of a common ancestor, given that the ancestry of these non-Jewish patients, like the Ashkenazim, can be traced to eastern Europe.
|Number of pages
|American Journal of Human Genetics
|Published - Apr 1990