SOD1 and amyotrophic lateral sclerosis: Familial forms of ALS on the other hand were found to be associated with mutations in the superoxide dismutase gene (SOD1), with SOD1 mutant protein being shown to reduce functional EAAT2 protein levels in animal models by initiating the cleavage of EAAT2 by Caspase-3 [183,184,185,186].