About this condition
Prothrombin G20210A — Thrombophilia
Prothrombin G20210A (Factor II mutation, rs1799963) is the second most common inherited thrombophilia after Factor V Leiden, present in approximately 2-3% of European ancestry populations. The 3' UTR variant increases prothrombin mRNA stability, leading to ~30% elevated prothrombin levels and 2-5x increased risk of venous thromboembolism (DVT and PE).
Clinical impact is greatest when compounded with other thrombophilia variants. Prothrombin G20210A + Factor V Leiden heterozygosity increases VTE risk approximately 20x. Homozygous prothrombin G20210A (~1 in 10,000) confers higher risk requiring primary prophylaxis consideration. These compound genotypes change anticoagulation duration from time-limited to potentially lifelong.
Prothrombin testing has direct clinical implications for: anticoagulation duration after first VTE (extended vs. time-limited), hormonal contraception counseling (estrogen-containing contraceptives increase VTE risk further in carriers), pregnancy management (LMWH prophylaxis consideration), and surgical prophylaxis (extended anticoagulation post-operatively).
Estrogen-containing contraceptives increase VTE risk ~4x in the general population. In prothrombin G20210A carriers, this risk compounds further. Genetic testing before hormonal contraception prescribing prevents potentially fatal pulmonary embolism.
- Gene locus
- F2 (11p11.2)
