C9ALS/FTD appears to involve haploinsufficiency of C9orf72 (DeJesus‐Hernandez et al, 2011; Cooper‐Knock et al, 2012; Gijselinck et al, 2012, 2015; Belzil et al, 2013; Ciura et al, 2013; Donnelly et al, 2013; Mori et al, 2013b; Xi et al, 2013; Waite et al, 2014). The gene discussed is C9orf72; the disease is frontotemporal dementia.