MAPT and Alzheimer disease: Moreover, the Aβ42/Aβ40 (0.067 ± 0.019 versus 0.076 ± 0.020, P = 0.042) and Aβ42/P-tau181 ratios (2.24 ± 1.07 versus 6.51 ± 2.76, P < 0.001) were significantly lower, and the P-tau 181/T-tau ratio (2.84 ± 1.65 versus 1.48 ± 0.97, P < 0.001) was significantly higher, in Alzheimer’s disease patients than in CU controls.