Niemann-Pick disease type C (NPC) is a complex lysosomal lipidosis (lipid storage disease) that results in hepatosplenomegaly and progressive neurological involvement. NPC is the chronic neuronopathic form of Niemann-Pick diseases. NPC can be subdivided into two types: NPC1 which has the frequency of 95% and NPC2. In both types, intracellular transport of LDL-derived exogenous cholesterol is impaired and that will result in accumulation of non-esterified cholesterol in lysosomes causing delayed homeostatic reactions of cholesterol. Cultured fibroblasts showed a partial deficiency of sphingomyelinase activity. Sphingomyelinase is the enzyme that targets a distinctive lipid (sphingomyelin) in the cells. NPC can affect infants, children, or adults. Infants may have ascites and severe liver and respiratory diseases due to infiltration of the liver and the lungs. In 50% of the cases, the neonatal period is marked by prolonged cholestatic jaundice that may regress spontaneously, but sometimes it may progresses to rapidly fatal liver failure. Infants without liver or respiratory diseases will have hypotonia and developmental delay. Classically, the disease occurs in the middle to late childhood and characterized by the insidious onset of ataxia, vertical supranuclear gaze palsy (VSGP), and dementia. Dementia and psychiatric symptoms are more likely to present in affected adults. Dystonia and seizures are also common in NPC. Death usually occurs in the second or third decade due to aspiration pneumonia. Males and females are equally affected.