ATXN2 and amyotrophic lateral sclerosis: Of the ALS cohort, 14 were negative for known mutations in TARDBP, UBQLN2, FUS, ATXN2 and C9orf72, 5 had an intermediate polyglutamine (polyQ) expansion (27–33 CAG repeats) in ATXN2 (ALS-ATXN2), and 8 cases had a G4C2-hexanucleotide repeat expansion in C9orf72 (ALS-c9) (Table 2).