C9orf72 and frontotemporal dementia: Moreover, although the evidence has pointed out that the expression of DPRs is one of the causative factors for C9orf72-ALS/FTD based on the identification of DPRs in patient brains [12, 26, 29, 33, 61–68] and expression of DPRs without hexanucleotide-repeat RNA in animal models [33, 64], it is unknown whether DPR localisation correlates to neuronal loss.