Niemann-Pick disease type C (NPC) is a slowly progressive lysosomal storage disorder that is often fatal. It is resulted from mutation in the NP1 gene, in which it fails to transport fats and cholesterol out of the cells building up an accumulation of multiple tissue specific lipids in the lysosomes , in the cerebellum, liver and spleen.

Symptoms include vertical eye palsy, hearing loss, cerebellar ataxia, speech difficulties, dysphagia, progressive memory loss, seizures, dystonia, sleep disturbance, cataplexy, liver and spleen enlargement.

NPC is autosomal recessive, in which two copies of the gene were inherited. It is estimated that NPC occurs one in every 150,000 people.

There is no known cure and treatment is mainly focused on treating symptoms associated with the disease to help improve the quality of life in these patients.