Niemann-Pick disease is a rare inherited degenerative nerve disease which leads to the buildup of a fatty substance (sphingomyelin) in cells in the liver, spleen, lymph nodes, and bone marrow. Niemann-Pick disease is most commonly seen in families of Eastern European (Ashkenazi) Jewish heritage.

There is no treatment for Niemann-Pick disease. Support groups and counseling can be helpful for people with Niemann-Pick disease and for their families. Genetic testing is recommended to identify carriers of the disease and help guide decisions about having children.