A radical hypothesis for neurodegeneration.

Point mutations in the cytosolic Cu/Zn superoxide dismutase (SOD-1) gene have been detected in association with familial amyotrophic lateral sclerosis (FALS). SOD clears superoxide radical and is one of the body's principal defense mechanisms against oxygen toxicity. The finding of SOD variants in FALS is consistent with the hypothesis that free radicals contribute to the pathogenesis of FALS, and possibly to the pathogenesis of other neurodegenerative disorders such as Parkinson's disease, in which there is substantial evidence of oxidant stress. The implication of free radicals in the pathogenesis of neurodegenerative disorders raises the possibility that antioxidants might provide neuroprotective therapy.