In Niemann-Pick disease, what deficiency is responsible for its symptoms?

Niemann-Pick disease is caused by a deficiency of sphingomyelinase, an enzyme that plays a crucial role in the metabolism of sphingomyelin, a type of sphingolipid found in cell membranes. This deficiency leads to the accumulation of sphingomyelin in various organs, particularly the liver, spleen, and brain, resulting in the characteristic symptoms of the disease.

The symptoms of Niemann-Pick disease include hepatosplenomegaly, neurodegeneration, and, in some cases, respiratory issues and growth delays. The excessive accumulation of sphingomyelin disrupts cellular function, leading to the various systemic manifestations seen in affected individuals.

Other choices relate to different lysosomal storage disorders. Hexosaminidase A deficiency is associated with Tay-Sachs disease, while hexosaminidase B deficiency is not typically known to cause significant clinical symptoms. Galactocerebrosidase deficiency causes Krabbe disease. Understanding the specific enzyme deficiencies linked to each disorder is crucial for accurate diagnosis and management.