SOD1 and amyotrophic lateral sclerosis: To date, more than 200 SOD1 variations have been disclosed in ALS (https://alsod.iop.kcl.ac.uk/), occurring in 14.8% of European fALS patients and 30% of Asian fALS patients.496 Cu/Zn superoxide dismutase 1 (SOD1), encoded by SOD1, is an antioxidant enzyme that regulates mitochondrial and cytosolic superoxide levels.