C9orf72 and amyotrophic lateral sclerosis: Furthermore, RanGAP1 can directly interact with the intronic hexanucleotide (G4C2) in the C9orf72 repeat expansion (147, 164), and it accumulates in cytoplasmic punctae in the motor cortex of ALS C9orf72 patients in patient-derived iPSC neurons (147, 165).