C9orf72 and amyotrophic lateral sclerosis: Dipeptide-repeat proteins (DRPs), translated through repeat-associated non-ATG (RAN) translation from pathogenic G4C2 expansions in C9orf72 gene, are supposed to play a pivotal role in development of C9orf72-related neurological disorders such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD)1–4.