MAPT and Alzheimer disease: This accumulation subsequently disrupts axonal transport and microtubule synthesis, resulting in neurotoxicity.538,539 However, some literature reports a significant decrease in zinc level in AD patients and suggests that zinc deficiency is a potential risk factor of AD.540,541 The depletion of intracellular zinc destabilizes microtubules, triggering a chain reaction that includes the release of tau protein, hyperphosphorylation, and the formation of neurofibrillary tangles.