Multiple hypotheses are related to the pathogenesis of AD, such as the amyloid cascade hypothesis [13–15], tau protein hypothesis [16–18], cholinergic hypothesis [19], lipid metabolism disorder hypothesis [20], neuroinflammation hypothesis [21], and oxidative stress hypothesis [22], among which the amyloid cascade hypothesis and tau protein hypothesis provide the predominantly theoretical construct for AD. The gene discussed is MAPT; the disease is Disorder of lipid metabolism.