Alzheimer’s disease patients had lower plasma levels of Aβ42 (13.74 ± 4.92 versus 17.16 ± 4.37 pg/mL, P = 0.004) and Aβ40 (204.97 ± 44.4 versus 229.77 ± 50.3 pg/mL, P = 0.042) and higher plasma levels of T-tau (2.80 ± 1.07 versus 2.32 ± 0.77 pg/mL, P = 0.045) than CU controls. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.