Identify the disease linked to sphingomyelinase deficiency.

Sphingomyelinase deficiency is specifically associated with Niemann-Pick Disease. This disorder is characterized by the accumulation of sphingomyelin due to the lack of the enzyme sphingomyelinase, which is essential for the breakdown of sphingomyelin, a type of lipid found in cell membranes and involved in various cellular functions.

The pathophysiology of Niemann-Pick Disease leads to the buildup of sphingomyelin in various organs, particularly the liver, spleen, and brain, resulting in a variety of symptoms such as hepatosplenomegaly, neurological decline, and characteristic cherry-red spots in the macula. The disease can manifest in different forms, with Type A being the most severe and presenting in infancy.

While other lysosomal storage diseases such as Gaucher's Disease, Metachromatic leukodystrophy, and Tay-Sachs Disease involve various enzyme deficiencies and lead to the accumulation of different substrates, they do not involve sphingomyelinase. Gaucher's Disease is related to glucocerebrosidase deficiency, Metachromatic leukodystrophy involves arylsulfatase A deficiency, and Tay-Sachs Disease is a result of hexosaminidase A deficiency. Thus