C9orf72 and frontotemporal dementia: Despite lack of evidence in mouse models, several studies showed that loss of C9orf72 in worm and zebrafish models induces motor neuron degeneration and motor deficits (Ciura et al., 2013; Therrien, Rouleau, Dion, & Parker, 2013), suggesting loss of C9orf72 function may partially contribute to disease pathogenesis of C9orf72‐linked ALS/FTD (Moens et al., 2017).