Mutations affecting the frontline antioxidant SOD1 were the first discovered genetic cause of ALS4 and oxidative stress is a prominent feature of the disease.31 However, not all cases of ALS involve SOD1 mutations and not all ALS-associated SOD1 mutations are associated with loss of dismutase function.32 However, because SOD1 requires copper for its catalytic antioxidant activity,33 we examined levels of endogenous SOD1 in spinal cord tissue from Slc31a1+/− mice, copper-dependent dismutase activity of the enzyme, and lipid peroxidation levels as an indicator of oxidative stress. Here, SOD1 is linked to amyotrophic lateral sclerosis.