ATXN2 and amyotrophic lateral sclerosis: Thus, this study confirmed ATXN2 with the intermediate polyQ length as a genetic enhancer of ALS-FTD in zebrafish, but SCA2 pathogenic variants with longer polyQ (≥ 34) still need to be examined in the context of SCA2 with respect to their toxic effects especially affecting cerebellar neurons in zebrafish.