Abnormal protein processing, accumulation of amyloid plaques and tau protein abnormalities, the reduction in acetylcholine, dyslipidemia and hypercholesterolemia, oxidative stress and mitochondrial dysfunction, activation of inflammatory pathways are connected with AD pathogenesis but these futures are also indicated as common to both diseases—AD and T2DM. The gene discussed is MAPT; the disease is type 2 diabetes mellitus.