Niemann-Pickrsquo;s disease (NPD) is an inherited metabolic disease caused by the deposition of sphingomyelin and cholesterol in various organs of the body. The disease was first reported by Niemann in 1914 as the first case, and in 1922 Pick described in detail what was seen on pathological examination, hence the name. Two cases were first reported in China in 1963, and individual cases have been reported since then. What are the causes of cherry red discoloration in the macula of the fundus? The disease is autosomal recessive and is more common in Jews. It has been confirmed that types A and B of the disease are caused by a deficiency of sphingomyelinase. This enzyme is widely present in the lysosomes of many tissues and is also found in mitochondria and microsomes, especially in liver cells. Sphingolipids are found in the cell membrane and subcellular plasma membrane of all cells, including the stroma of erythrocytes. In the absence of this enzyme, these lipids are not hydrolyzed and accumulate in large amounts in the cells, often accompanied by deposition of cholesterol and bisphosphonates. The principle of the increase in cholesterol is unclear, but there appears to be a close relationship between cholesterol and sphingolipid metabolism, as well as a small increase in other neurospherin-like lipids, and in the cells of patients with types C and D, the main deposits are cholesterol and less sphingolipids, and the levels of sphingomyelinase in the cells are also reduced, between types A and B and normal subjects. A significant impairment in the esterification of exogenous cholesterol (esteriification) was found in the skin fibroblasts of the patients, and based on this possible pathogenesis, pure-sibling, carrier and prenatal diagnostic methods have been established, which is therefore considered to be the cause of this type. The gene for sphingomyelinase is located on chromosome 17, the structure of which is well understood, and the mutation of the gene for type C is on chromosome 18. The disease is characterized by feeding difficulties and malnutrition from 3 to 4 months of age, hepatomegaly and splenomegaly, often preceding splenomegaly, enlarged lymph nodes, and psychoneurological retardation, but because it proceeds slowly, it often goes undetected for several months after the onset of the disease, not only because it does not meet the developmental standards for each age, but also because it appears regressive and has decreased muscle strength. In severe cases, hearing and vision are affected or even lost. 30% to 50% of patients have cherry-red spots in the macula of the eye. The children gradually lose weight and often die before the age of 3-4 years due to secondary infections.