ATXN1 and cerebellar ataxia: Polyglutamine (PolyQ) spinocerebellar ataxias (SCA), including SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17, are diseases caused by the expansion of CAG trinucleotide repeats located in the coding region of specific genes, which results in an abnormally elongated polyQ tract in the corresponding proteins [1].