Gut microbiota has a direct impact on AD, for example, helicobacter pylori enhances tau protein hyperphosphorylation [23]; intestinal disorders can encourage amyloid aggregation, neuroinflammation, oxidative stress, and insulin tolerance in AD pathogenesis [22]; and changes in the composition of gut microbiota can increase the release of lipopolysaccharides (LPSs) and amyloid, which may promote AD pathogenesis [24]. The gene discussed is MAPT; the disease is Alzheimer disease.