C11: Vitamin K antagonist as first-line anticoagulant for atrial fibrillation, unless there is concurrent metallic heart valve in situ, moderate-to-severe mitral stenosis, or creatinine clearance less than 15mL/min (direct thrombin inhibitor or factor Xa inhibitors are equally efficacious and safer than vitamin K antagonists). The gene discussed is F10; the disease is Mitral stenosis.