A hereditary autosomal dominant spinocerebellar ataxia with onset typically between 20 and 30 years of age. It is characterized by gait abnormalities; limb ataxia, DYSARTHRIA; slow and lower limb HYPERREFLEXIA; OCULAR MOTILITY DISORDERS; and BLEPHAROPTOSIS. Mutations in the AFG3L2 gene have been identified. OMIM: 610246