Spinocerebellar ataxia type 3 (SCA3), also called Machado–Joseph disease (MJD), is a dominantly inherited genetic disease resulting from the special type of mutation–expansion of CAG repeats in the ATXN3 gene [1] (MJD and ATXN3: OMIM 109150 and 607047). This evidence concerns the gene ATXN3 and hereditary disease.