Adult onset Niemann-Pick disease type C presenting with psychosis

Niemann-Pick disease type C (NPC) is an autosomal recessive neurometabolic disorder that rarely presents in adulthood, and is associated with cognitive decline, various movement disorders (ataxia, chorea, dystonia, and myoclonus), a vertical supranuclear gaze palsy (VSGP), and seizures. A recent case report demonstrated a delay in diagnosis of eight years when a patient with NPC presented with psychosis. This article reviewed all cases seen at the Mayo Clinic with a possible diagnosis of NPC between 1976 and 2000. Of the 52 possible cases, five had an established diagnosis of adult onset NPC. Of these, two presented with psychosis and were not diagnosed with NPC for 5 and 15 years, respectively. NPC may initially present in adulthood with psychosis, and when psychosis is associated with VSGP, various dyskinesias, and seizures, NPC should be suspected.