ATXN7 and Huntington disease: SCA7 thus belongs to the family of polyQ expansion disorders, also named polyQ diseases, a group of neurodegenerative disorders comprising spinobulbar muscular atrophy (SBMA) [2], Huntington’s disease (HD) [3], dentatorubral-pallidoluysian atrophy (DRPLA) [4] and spinocerebellar ataxia (SCA) 1, 2, 3, 6, 7, and 17 [1], [5]–[13].