SOD1 and amyotrophic lateral sclerosis: Some of the main proposed mechanisms of motor neuron apoptosis in ALS include inflammation, glutamate-induced excitotoxicity, free radical build-up from superoxide dismutase type 1 (SOD1) point mutations, repeat-associated non-ATG translation due to C9ORF72 mutations, TAR DNA-binding protein 43 (TDP-43) proteinopathy, and aggregation-prone proteins [1,2,5,9,11,12].