Psychosis as the initial manifestation of adult-onset Niemann-Pick disease type C.

Niemann-Pick disease type C (NPC) is a neurometabolic genetic disorder that is distinguished from Niemann-Pick disease by its later onset, more insidious progression, variable visceromegaly, and abnormalities of intracellular cholesterol metabolism. We describe a patient who presented with an 8-year history of psychosis requiring chronic neuroleptic therapy for a presumed diagnosis of schizophrenia. He was subsequently diagnosed with NPC as the emerging features of dementia, ataxia, dysarthria, and vertical supranuclear ophthalmoplegia were recognized. The characteristic features of adult-onset NPC and the obstacles to early diagnosis are reviewed.