SOD1 and amyotrophic lateral sclerosis: Among the genetic causes of ALS, 15–20 % of familial ALS cases and about 5 % of sporadic ALS cases are associated with multiple mutations in the gene for Cu,Zn-superoxide dismutase (SOD1), which imparts an increase in a novel toxic function to this otherwise superoxide radical scavenging enzyme in normal conditions [4].