ATXN2 and amyotrophic lateral sclerosis: For example, ATXN2 encodes a polyglutamine protein associated with spinocerebellar ataxia 2 (Imbert et al., 1996) and contains an expansion that also confers increased susceptibility to ALS in sporadic (Elden et al., 2010), and possibly C9 (van Blitterswijk et al., 2014), cases.