ATXN2 and spinocerebellar ataxia type 2: In connection to neurodegenerative disease, polyglutamine (polyQ) repeat expansions in ATXN2 cause spinocerebellar ataxia type 2 (SCA2) and increase the risk for development of ALS (Elden et al, 2010; Nussbacher et al, 2019; Glass et al, 2022).