Fifth, multivariable MR simultaneously adjusting for genetic predictors of factor XI and prekallikrein levels revealed a significant residual association of factor XI levels with ischemic stroke (odds ratio [OR] of ischemic stroke per 1-SD increase in adjusted factor XI levels, 1.12 [95% CI, 1.08–1.16]; P=1.33×10−10) and no residual association of genetically proxied KLKB1 levels with ischemic stroke (OR per 1-SD increase in KLKB1, 1.02 [95% CI, 0.99–1.05]; P=0.12). The gene discussed is KLKB1; the disease is ischemic stroke.