Sphingomyelinase deficiency is another name of Niemann-Pick disease that refers to a biochemical disorder affecting a lipid (fat) called sphingomyelin which results resulting usually in prog ressive enlargement of the liver and spleen (hepatosplenomegaly), "swollen glands" (lymphadenopathy), anemia and mental and physical deterioration. Niemann-Pick disease is hereditary and follows an autosomal recessive pattern.

Sphingomyelinase deficiency is also called Sphingomyelin lipoidosis. (See Niemann-Pick)