Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease, is the most common subtype of type 1 autosomal dominant cerebellar ataxia (ADCA type 1), a neurodegenerative disorder, and is characterized by ataxia, external progressive ophthalmoplegia, and other neurological manifestations. The disease is Monarch Disease Ontology identifier MONDO_0007182 (Machado-Joseph disease). Also known as: Azorean disease, Azorean disease of the nervous system, MJD, Machado disease, Nigro-spino-dentatal degeneration with nuclear ophthalmoplegia, SCA3, autosomal dominant striatonigral degeneration, spinocerebellar ataxia 3.