This suggests that loss of nuclear FUS function may contribute to ALS pathogenesis, although evidence from ALS-FUS mouse models indicates that ALS-FUS mutations also result in a novel toxic function that triggers motor neuron degeneration (Scekic-Zahirovic et al., 2016, 2017; Sharma et al., 2016). This evidence concerns the gene FUS and amyotrophic lateral sclerosis.