FUS and amyotrophic lateral sclerosis: Global or motor neuron–specific knockout of FUS gene in mice does not cause motor deficits (Sharma et al., 2016), whereas transgenic mice expressing wild-type or mutant FUS were shown to develop severe motor impairments and exhibit progressive neurological symptoms, suggesting a mechanism of toxic gain of function rather than loss of function in FUS-linked ALS pathogenesis (Qiu et al., 2014; Scekic-Zahirovic et al., 2017; López-Erauskin et al., 2018).