Adult-onset Niemann-Pick disease type C presenting as progressive chorea mimicking Huntington's disease.

The etiologies of progressive generalized chorea in adults are typically acquired or genetic causes, such as Huntington's disease (HD). We present the case of a 43-year-old woman who experienced progressive generalized chorea and cognitive decline over the course of 8 years. Abnormal eye movements, such as the "round-the-houses" and "zig-zag" signs, were observed. Brain MRI showed caudate atrophy, with a phenotype resembling HD. A rare genetic etiology of Niemann-Pick disease type C (NPC) was ultimately identified as the final diagnosis for this index patient. In this movement disorder round, we describe our approach to this clinical presentation and highlight the features following appropriate treatment.