An atypical form of Sandhoff's disease. Case report and biochemical studies.

A case of Sandhoff's disease (GM2 gangliosidosis type 2) is reported because of an unusual course with later onset of symptoms, more slow progress and longer survival than those previously described. Otherwise the patient presented most of the classical symptoms of the disease with a final state of blindness, deafness and decerebrate rigidity. The residual acidic hexosaminidase isozymes in liver and brain tissue were Hex A and Hex S, while Hex B was barely detectable. The neutral hexosaminidase form called Hex C was also found. Two urinary oligosaccharides containing N-acetylglucosamine and mannose were found to be execreted by the patient.