Diagnosis of Tay-Sachs disease using [3H]N-acetylneuraminic acid labelled GM2 ganglioside as substrate.

GM2 ganglioside labelled with tritium in the N-acetylneuraminic acid moiety was prepared and used to measure beta-hexosaminidase A activity in cultured humans skin fibroblasts extracts. The latter convert this substrate to the correspondingly labelled GM3 ganglioside which can easily be separated from the substrate by thin-layer chromatography. No cleavage of the N-acetylneuraminic acid group was observed under our conditions. Two methods are described for the determination of GM2-beta-hexosaminidase A activity in fibroblasts. The application of these methods to the diagnosis of Tay-Sachs disease is discussed.