Based on the currently known risk factors for AD and the processes underlying its pathophysiology, three hypotheses/mechanisms can be distinguished for the development of AD: the cholinergic hypothesis, which relies on the disruption/loss of cholinergic neurotransmission, specifically acetylcholine in the central nervous system (CNS); the formation of neurotoxic amyloid-β, which aggregates into plaques and impairs neuronal communication; and the accumulation of Tau protein, which becomes hyperphosphorylated, damaging neurons [5]. This evidence concerns the gene MAPT and Alzheimer disease.