ATXN2 and amyotrophic lateral sclerosis: In this context, STRs expansions have already been linked to the ALS/frontotemporal spectrum disorder (ALS/FTD) development (e.g., C9ORF72 hexanucleotide G4C2 expansions) (19, 20) or identified as risk factors (e.g., CAG trinucleotide expansions in ATXN2) (4, 21), and could represent a valuable starting point to further investigate and clarify the genetic predisposition of sporadic cases as well.