SOD1 and amyotrophic lateral sclerosis: Among the known ALS-related gene mutations, SOD1, TARDBP and FUS mutations are common genetic factors that explain a relatively large proportion of FALS and SALS cases, whereas mutations of other related genes, such as SQSTM1, OPTN, TUBA4A and ARHGEF28, are less common (Ma et al., 2014; Li et al., 2015a,b; Yang et al., 2015).