Type 2 GM1 gangliosidosis with long survival and neuronal ceroid lipofuscinosis.

Neurologic deterioration began in a girl before age 2 years. By 4 she was spastic and decerebrate. GM1 gangliosidosis was diagnosed by absence of beta-galactosidase activity in leukocytes and fibroblasts. She died at 17 years. Her small brain contained only 2.61 mumole glycolipid N-acetylneuraminic acid per gram, and was filled with autofluorescent material. GM1 gangliosidosis was confirmed by the presence of membranous cytoplasmic bodies, by the absence of beta-galactosidase, and by failure of complementation when the patient's fibroblasts were fused with cells from other forms of GM1 gangliosidosis. The autofluorescent material probably accumulated because of the long survival rather than the primary enzyme defect.