Evidence check: VKORC1 in the context of Müdigkeit

The link between VKORC1 and fatigue lacks robust scientific evidence. VKORC1 encodes vitamin K epoxide reductase, a key enzyme in vitamin K metabolism. Genetic variants (e.g., rs9923231) are well-known for influencing warfarin dosing, but a direct effect on fatigue without anticoagulation is speculative. In theory, altered vitamin K activity could affect coagulation or bone health, but fatigue is a nonspecific, multifactorial symptom. The provided context contains no validated studies linking VKORC1 to fatigue. Therefore, the evidence is rated as unclear. VKORC1 testing is primarily relevant for pharmacogenetics (warfarin), not for general tiredness. Persistent fatigue should be evaluated clinically for common causes like iron deficiency, thyroid dysfunction, or sleep disorders.