Adult dystonic lipidosis: clinical, histologic, and biochemical findings of a neurovisceral storage disease.

A 43-year-old man presented with splenomegaly and a 20-year history of a neurologic disorder that included vertical supranuclear ophthalmoplegia, mild dementia, and a movement disorder. Adult dystonic lipidosis was diagnosed from the clinical picture and demonstration of foamy and sea-blue histiocytes in bone marrow. Ultrastructural patterns in cytolysosomes suggested accumulation of neutral fat and phospholipids. Liver content of bis-(monoacylglycerol) phosphate was increased, probably because the number of lysosomes had increased. Sphingomyelinase activity was normal in cultured skin fibroblasts. Juvenile and adult dystonic lipidosis form a clinically, histologically, and biochemically distinct neurovisceral storage disease that differs from Niemann-Pick disease.