Any of a group of inherited diseases characterized by progressive spastic paralysis, blindness, convulsions, mental retardation, and, ultimately, death, and caused by abnormal phospholipid metabolism. The disease occurs almost exclusively in individuals of eastern European Jewish descent in four enzymatically distinct forms: infantile (Tay-Sachs disease); early juvenile (Jansky-Bielschowsky disease); late juvenile (Spielmeyer-Vogt disease); and adult (Kufs disease). Also called cerebral lipidosis.