SOD1 and amyotrophic lateral sclerosis: Superoxide dismutase 1 (SOD1), a protein misfolding2 enzyme, is one of the earliest definitive ALS genes identified in 19933 and along with TAR DNA-binding protein-43 (TDP-43) aggregate formation in the cytoplasm4 are a common defining hallmark of ALS in both familial and sporadic pathologies.