A vitamin K epoxide reductase complex subunit 1 mutation in an Irish patient with warfarin resistance

Background Oral anticoagulant use continues to increase rapidly. In this setting, it is important to recognise that some normal individuals can demonstrate resistance to anticoagulation with warfarin. Such patients require high daily doses of warfarin (>20 mg) in order to maintain an international normalised ratio (INR) within the target therapeutic range (2–3). We describe the case of an elderly gentleman with atrial fibrillation who demonstrated true warfarin resistance.