ATXN2 and amyotrophic lateral sclerosis: Alleles of ≥31 CAG repeats have also been shown to be risk alleles for amyotrophic lateral sclerosis with or without frontotemporal dementia, suggesting ATXN2 pathogenic mechanisms are complex and dynamic (Glass et al., 2022), and that other variants or genes may be implicated in the variable pathogenesis.