MONDO_0011781 (spinocerebellar ataxia type 17) is a rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I). It is characterized by a variable clinical picture which can include dementia, psychiatric disorders, parkinsonism, dystonia, chorea, spasticity, and epilepsy. Also known as: CPD2, HDL4, Huntington disease-like 4, OPCA V, OPCA with dementia and extrapyramidal signs, SCA 17, SCA17, cerebelloparenchymal disorder II.