Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited neurodegenerative disorder caused by large expansions in an unstable polyglutamine domain within the protein ataxin-2 (ATXN2), probably through a toxic gain-of-function mechanism [1–3]. Here, ATXN2 is linked to spinocerebellar ataxia type 2.