MAPT and Alzheimer disease: Patients with CAA had lower plasma p‐tau 217 (0.69 ± 0.76 vs. 1.28 ± 0.97 pg/mL, p < 0.001) and a lower p‐tau 217/Aβ40 ratio (0.003 ± 0.002 vs. 0.006 ± 0.003, p < 0.001) than the AD group but higher levels than the DPA group (p‐tau 217, 0.27 ± 0.13 pg/mL, p = 0.001; p‐tau 217/Aβ40, 0.001 ± 0.0005, p < 0.001), although adjustment attenuated the difference in p‐tau 217 between CAA and DPA.