A crucial driver of C9ORF72-mediated ALS/FTD pathology is the unconventional repeat-associated non-AUG (RAN) translation of the HRE into five toxic dipeptide repeat (DPR) species: poly-PA, poly-GA, poly-PR, poly-GR, and poly-GP. This evidence concerns the gene C9orf72 and frontotemporal dementia.