MSH: An autosomal recessive lipid storage disorder that is characterized by accumulation of CHOLESTEROL and SPHINGOMYELINS in cells of the VISCERA and the CENTRAL NERVOUS SYSTEM. Type C (or C1) and type D are allelic disorders caused by mutation of gene (NPC1) encoding a protein that mediate intracellular cholesterol transport from lysosomes. Clinical signs include hepatosplenomegaly and chronic neurological symptoms. Type D is a variant in people with a Nova Scotia ancestry.,NCI: An autosomal recessive inherited lysosomal storage disease caused by mutations in the NPC1 and NPC2 genes. It is characterized by progressive neurologic deterioration manifested with ataxia, dementia, seizures, and dystonia. Other signs and symptoms include hepatosplenomegaly, jaundice, and respiratory failure.