MAPT and Cognitive impairment: Superoxide dismutase 2 (SOD2) and heme oxygenase 1 are two antioxidant enzymes that decline in brain cells during aging.77,78 SOD2 protects neurons against decrements in energy availability and Aβ toxicity, and experimental reduction of SOD2 levels accelerates the onset of cognitive deficits in APP mutant transgenic AD mice.79 Moreover, that SOD2 deficiency can trigger Tau hyperphosphorylation80 suggests a role for elevated mitochondrial oxidative stress in AD, FTD and other ‘Tauopathies’.