In terms of composite biomarkers, CAA patients also had a lower p‐tau 217/t‐tau ratio (0.29 ± 0.22 vs. 0.51 ± 0.37, p = 0.013), lower p‐tau 217/Aβ40 ratio (0.003 ± 0.002 vs. 0.006 ± 0.003, p < 0.001, Figure 2B), and lower p‐tau 217/Aβ42 ratio (0.066 ± 0.044 vs. 0.131 ± 0.058, p < 0.001, Figure 2C) than the AD group. The gene discussed is MAPT; the disease is Alzheimer disease.