Detection of GM2-gangliosidosis (Tay-Sachs and Sandhoff disease) gene carriers by serum hexosaminidase assay.

With a view to the biochemical detection of homo- and heterozygous carriers of GM2-gangliosidosis, serum hexosaminidase activities were investigated in patients from Tay-Sachs and from Sandhoff disease, respectively, in their relatives, and in normal controls. Two related methods for the differential determination of hexosaminidase A and B activities were tested. Homozygous carriers (patients) were detected by both methods in a similar manner. As regards the identification of heterozygous carriers more conclusive results were attained by the "heat inactivation method" (O'Brien, J.S., Okada, S., Chen, A. and Fillerup, D.L. (1970) New Engl. J. Med 283, 15).