Tay-Sachs' and Sandhoff's diseases: the assignment of genes for hexosaminidase A and B to individual human chromosomes.

The techniques of somatic cell genetics have been used to establish the linkage relationships of loci coding for two forms (A and B) of hexosaminidase (EC 3.2.1.30; 2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase) and to determine whether a structural relationship exists between these forms. In a series of human-mouse hybrid cell lines, hexosaminidase A and B segregated independently. Our results and those reported by other investigators are used to analyze the proposed structural models for hexosaminidase. We have also been able to establish a syntenic relationship between the gene locus responsible for the expression of hexosaminidase A and those responsible for mannosephosphate isomerase and pyruvate kinase-3 and to assign the gene for hexosaminidase B to chromosome 5 in man. There is thus a linkage between specific human autosomes and enzymes implicated in the production of lipid storage diseases.