any one of a group of inherited diseases characterized by failure to thrive, hypertonicity, progressive spastic paralysis, loss of vision and occurrence of blindness, usually with macular degeneration and optic atrophy, convulsions, and mental deterioration; associated with abnormal storage of sphingomyelin and related lipids in the brain. Four types are recognized as clinically and enzymatically distinct: infantile type (Tay-Sachs disease, GM2 gangliosidosis) due to a deficiency of hexosaminidase A; early juvenile type (Jansky-Bielschowsky or Bielschowsky disease); late juvenile type (Spielmeyer-Vogt disease; Spielmeyer-Sjögren disease; Vogt-Spielmeyer disease; Batten-Mayou disease; Batten disease; ceroid lipofuscinosis); and adult type (Kufs disease). SYN: cerebral lipidosis.