C9orf72 and frontotemporal dementia: Given the evidence in support of a role for the hexanucleotide repeat-containing RNAs in C9ORF72-linked ALS and FTD – hereafter referred to as C9-ALS/FTD – strategies for silencing their production hold potential for the disorder25–30, as they can inhibit the formation of the abnormal RNA foci25,27 and DPR proteins31,32.