Niemann-Pick type C (NP-C) disease is a rare neurodegenerative
lysosomal storage disorder. It is highly heterogeneous, and there is limited awareness
of a substantial subgroup that has an attenuated adolescent/adult-onset disease.
In these patients psychiatric features, often a psychosis, may dominate the initial
impression, although often there is an associated ataxia and cognitive impairment.
Typically, patients experience a substantial diagnostic delay. In this review we
highlight the importance of early recognition and discuss the pathophysiology,
neuropsychiatric presentation and recent changes in the investigation and work-up of
these patients, and treatment options.