MAPT and Alzheimer disease: Serum p-tau (pSer202: S202) was also slightly higher in the MCI and Mild-AD groups compared to the AMCs, but the differences did not reach significance (AMC, 98.60 ± 16.23; MCI, 127.0 ± 20.07; Mild-AD, 120.1 ± 17.84, p = 0.38, Figure 1B).