Spinocerebellar ataxia type 3 (SCA3, Machado-Joseph disease) is a rare movement disorder which caused by an abnormal expansion of the polyglutamine (polyQ) tract in the causative ATXN3 protein (Kawaguchi et al., 1994; Rezende et al., 2018). The gene discussed is ATXN3; the disease is Machado-Joseph disease.