The levels of Aβ1-42 (p = 0.726 in A–T + patients, p = 0.100 in A + T– patients), Aβ1-40 (p = 0.726 in A–T + patients, p = 0.100 in A + T– patients), p-tau181 (p = 0.161 in A–T + patients, p = 0.068 in A + T– patients), t-tau (p = 0.889 in A–T + patients, p = 0.361 in A + T– patients), and the ratios of Aβ1-42/Aβ1-40 (p = 0.753 in A–T + patients, p = 0.314 in A + T– patients) and t-tau/Aβ1-42 (p = 0.363 in A–T + patients, p = 0.201 in A + T– patients) were similar in A–T + and A + T– patients with and without T2DM. The gene discussed is MAPT; the disease is type 2 diabetes mellitus.