A lysosomal storage disease due to sphingomyelin accumulation in the reticuloendothelial system; there are five types distinguished by age of onset, amount of central nervous system involvement, and degree of enzyme deficiency. At least some types are characterized by foamy reticular cells containing phospholipids which infiltrate the liver, spleen, lungs, lymph nodes, and bone marrow.Niemann- Pick disease Type A and B occur due to the deficiency of an enzyme called acid sphingomyelinase (ASM). This enzyme is required for breaking down sphingomyelin, which is a product of fat metabolism. The lack of ASM leads to the collection of sphingomyelin or cholesterol in the body. Niemann-Pick disease Type C arises due to a defect in cholesterol and glycolipid transport mechanisms. According to another classification, Niemann-Pick disease is classified into two types: Niemann-Pick disease, SMPD1-associated (which includes Type A and Type B disease), and Niemann-Pick disease, Type C.
Some forms of the disease can be diagnosed during ante natal screening. After birth, the diagnosis is made by a liver biopsy where liver tissue specimens are obtained and studied under a microscope. Niemann-Pick disease does not have a complete cure, though treatments that halt the disease progression are being studied. Affected children tend to die of infection or progressive dysfunction of the central nervous system.No specific treatment is known for type A, but symptoms are treated. In adult patients with type B, physicians try to keep cholesterol levels down to normal levels. Results of a survey shows the extrapolation of Prevalence Rate of Niemann-Pick disease type C2 in Japan is 848.Niemann-Pick Type C is a genetic, cholesterol storage disorder that primarily strikes children with death occurring before or during adolescence. There is also an adult onset form of the disease.