Machado-Joseph Disease (MJD-III), also called spinocerebellar ataxia type III, is a rare, muscle weakness and ataxia characterized by the slow degeneration of the hindbrain. Affected individuals may eventually become disabled and/or paralyzed but intelligence is not affected. The onset of symptoms of MJD varies from early teens to late adulthood. It is inherited in an autosommal dominant manner and is caused by a (CAG)n trinucleotide repeat expansion in the ataxin-3 gene (ATXN3).