Myths vs facts: VKORC1 and fertility

The claim that VKORC1 variants directly affect fertility is not supported by strong evidence. VKORC1 encodes an enzyme involved in vitamin K metabolism, primarily relevant for blood coagulation and warfarin sensitivity. Some studies have explored associations between VKORC1 polymorphisms and miscarriage risk or endometriosis, but findings are inconsistent and effect sizes are small. The evidence is mostly mechanistic or from underpowered association studies; no randomized controlled trials demonstrate a causal link to fertility. Therefore, labeling VKORC1 as a 'fertility gene' is misleading. Consumers considering genetic testing for VKORC1 should understand that its clinical utility for fertility is unclear. The established role remains pharmacogenetics for warfarin dosing. For fertility concerns, other factors (hormonal, anatomical, lifestyle) are far more relevant. Genetic testing should not replace a thorough medical evaluation.