Over the last decade, numerous studies have focused on discovering the role of repeat expansions (REs) other than C9orf72 in ALS, such as ATXN1 (Ataxin-1, OMIM * 601556) and ATXN2 (Ataxin-2, OMIM * 601517). This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.