Other names: ASMD; Sphingolipidosis

Acid sphingomyelinase deficiency (ASMD), historically known as Niemann-Pick disease types A, A/B, and B, is a lysosomal storage disease that results from reduced activity of the enzyme acid sphingomyelinase (ASM). It is an extremely rare, progressive genetic disease caused by pathogenic variants in the sphingomyelin phosphodiesterase 1 gene.

ASM is an enzyme that degrades sphingomyelin to ceramide and phosphocholine. The deficiency of ASM causes an intra-lysosomal accumulation of sphingomyelin (as well as cholesterol and other cell membrane lipids) in various tissues.

Signs and symptoms of ASMD can present in infancy, childhood, or adulthood, and may include enlarged spleen or liver, difficulty breathing, lung infections, and unusual bruising or bleeding, among other disease manifestations. 

Xenpozyme (olipudase alfa-rpcp) is the first FDA-approved treatment for ASMD. It is a hydrolytic lysosomal sphingomyelin-specific enzyme replacement therapy, designed to replace deficient or defective acid sphingomyelinase (ASM).

Drugs used to treat Acid Sphingomyelinase Deficiency