Significant progress has been made in understanding the mechanisms underlying ALS/FTD, leading to the proposal of three main mechanisms: the accumulation of toxic RNAs with repeat sequences (22,23), loss-of-function of the C9orf72 encoded proteins (24), and the production of toxic peptides and proteins through a process called non-ATG translation (25,26). This evidence concerns the gene C9orf72 and frontotemporal dementia.