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. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.