Machado-Joseph disease (MJD), or spinocerebellar ataxia type 3 (SCA3), is a neurodegenerative disorder caused by an expansion in the number of CAG repeats in the ATXN3/MJD1 gene resulting in an expanded polyglutamine tract in the ataxin-3 protein [51, 63]. Here, ATXN3 is linked to Machado-Joseph disease.