There are many known SOD1 mutations, and they are responsible for 12 ​% of the incidence of familial ALS and 1–2% of the incidence of sporadic ALS [153,156] It should be noted that SOD1 ALS lacks the TDP-43 pathology that is present in nearly every other ALS case. Here, SOD1 is linked to amyotrophic lateral sclerosis.