MAPT and Alzheimer disease: AD is the most common clinical senile degenerative cognitive disorder.542 Although tau protein aggregation and beta-amyloid protein (Aβ) accumulation play central roles in the pathophysiological hypothesis of AD, the potential role of metal overload, subsequent oxidative stress, and tissue damage cannot be ignored.543–545 Increased levels of iron in the brain are an important feature of AD patients, and have been reported since as early as the 1950s.