SOD1 and amyotrophic lateral sclerosis: In recent years, research in SOD1 animal ALS models has found MN pathology to begin at the distal axon terminals and to proceed in a “dying back” pattern (Fischer et al., 2004; Xie et al., 2005; Parkhouse et al., 2008; Shi et al., 2009; Carrasco et al., 2010).