We searched PubMed and SCOPUS for papers published between January 1, 2000, and July 28, 2016, with the following terms: “spinocerebellar ataxia type 2,” “SCA2,” “SCA2 phenotype,” “SCA2 genetics,” “SCA2 diagnosis,” “SCA2 treatments,” “preclinical stage,” “prodromal stage,” “presymptomatic stage,” “mutation carriers,” “preclinical carriers,” and “presymptomatic subjects.” We used no language restrictions. Here, ATXN2 is linked to spinocerebellar ataxia type 2.