Linear models covarying for age at plasma, plasma‐to‐death interval, and sex confirmed that GFAP was significantly higher in αSyn+AD than αSyn (β = 0.31, 95% CI = 0.065–0.56, P = 0.015) with large effect size (η2G = 0.14; 95% CI = 0.021–1.0); plasma p‐tau181 was not significantly higher in αSyn+AD than αSyn (P = 0.37). The gene discussed is GFAP; the disease is Alzheimer disease.