Niemann-Pick disease

Disease Overview

Niemann-Pick disease (NPD) is a group of inherited metabolic disorders in which harmful quantities of a fatty substance (lipids) accumulate in the spleen, liver, lungs, bone marrow, and brain.[1786][1787] Symptoms may include lack of muscle coordination, brain degeneration, learning problems, loss of muscle tone, increased sensitivity to touch, spasticity, feeding and swallowing difficulties, slurred speech, and an enlarged liver and spleen.[1786] Inheritance is autosomal recessive.[1787][1788]

Niemann-Pick disease is divided into four main types according to the altered (mutated) gene and the signs and symptoms:[1786][1788]

• Type A, caused by mutations in the SMPD1 gene. It is the most severe form, occurs in early infancy and is seen primarily in Jewish families.
• Type B , caused by mutations in the SMPD1 gene. Usually occurs in children, and affects the liver, spleen and lungs (visceral form), but generally does not affect the brain.
• Type C1, caused by mutations in the NPC1 gene. May occur at any age and affect the brain and the viscera.
• Type C2, caused by homozygous mutation in the NPC2 gene. Similar to type C1, but more severe, and mostly affecting the lungs.

Some classify type A and B as “acid sphingomyelinase (ASM) deficiency”.[13642] NP type D is now considered as type C (when affected people are from Nova Scotia, Canada); other rarer types have being described.[1788][1787]

There is currently no effective treatment for type A. Bone marrow transplantation, enzyme replacement and gene therapies may be helpful for people with type B.[1786]  A medication called Miglustat has been shown to stabilize certain neurological symptoms in people with type C. Currently other treatments are under clinical investigation.[1787][13644]