ATXN2 and Huntington disease: SCA type 1 (SCA1), at least five additional SCAs (SCA2, 3, 6, 7 and 17) and other neurodegenerative disorders, such as Huntington disease (HD), are caused by proteins with abnormally long polyglutamine tracts as common cause in pathogenesis (Durr, 2010; Schöls et al., 2004; Paulson, 2009; Orr and Zoghbi, 2007).