Niemann-Pick disease types A and B are inherited disorders that can affect many different body systems.
Symptoms can include an enlarged liver or spleen, loss of mental abilities and movement after turning one, lung damage, and lung infections. Symptoms of type A Niemann-Pick disease present in early infancy. Symptoms of type B Niemann-Pick disease usually present in mid-childhood.
This condition is caused by pathogenic (disease-causing) variants in the SMPD1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 90 chance to be a carrier. Carriers typically do not experience any symptoms.
Other names for this condition include SMPD1-related Niemann-Pick disease, neuronal cholesterol lipidosis, sphingomyelin lipidosis, and sphingomyelinase deficiency.