The 13 studies included in the present meta-analysis involved a total of 154 positive carriers of 30–33 CAG repeats in the ATXN2 gene among 9,042 ALS cases (including fALS cases with no known monogenic mutations), and 46 positive carriers of the same CAG repeats among 13,116 controls. The gene discussed is ATXN2; the disease is amyotrophic lateral sclerosis.