Task-related MEG studies have shown cortical dysfunction in C9orf72 carriers (repeat expansion; associated with both ALS and FTD (DeJesus-Hernandez et al., 2011)) prior to the development of motor symptoms, resembling findings in symptomatic ALS patients (Proudfoot et al., 2017). The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.