F2
Coagulation factor II (prothrombin)
Gene Number: 2147
Location: 11p11.2
Key Functions: Blood clotting, thrombin production, prevention of blood loss
F2 provides instructions for making prothrombin, a protein produced mainly in the liver. During clotting, prothrombin becomes thrombin, which helps form the fibrin mesh that seals damaged blood vessels [R].
This report examines rs1799963, also called prothrombin G20210A. The A allele increases prothrombin production and the likelihood of blood clots forming in veins, including deep vein thrombosis (DVT) and pulmonary embolism (PE).
Explore your genotype below, or visit our F5 and Factor V Leiden report to learn about another inherited influence on blood clotting.
SNP ID | Your Genotype | Alt Allele | Interpretation |
|---|---|---|---|
rs1799963 | Analyze your DNA to see your genotype | A | Analyze your DNA to see a personalized result. |
rs1799963 — Prothrombin G20210A
GG – Linked to normal prothrombin levels; typical venous thrombosis risk [R].
AG – Associated with higher prothrombin levels and increased venous blood-clot risk. A 2024 meta-analysis estimated approximately 2.2× the odds of venous thromboembolism compared with noncarriers [R].
AA – Homozygous—A rare genotype associated with greater venous blood-clot risk. A meta-analysis from 2024 estimated approximately 5.2× the odds compared with noncarriers [R].
Functional effect: G20210A lies in the gene’s 3′ untranslated region. It increases prothrombin production without changing the protein’s amino-acid sequence, making clot formation more likely (R).
What This Means for You
Many people with this variant never develop a blood clot. Risk also depends on factors such as surgery, prolonged immobility, pregnancy, estrogen-containing medication and the presence of Factor V Leiden [R]. If your raw DNA shows AG or AA, arrange clinical confirmation and discuss the result with a healthcare professional, particularly before surgery, pregnancy or estrogen use. One copy alone does not automatically mean you need long-term blood-thinning treatment
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