Prothrombin clotting variant

Prothrombin is a blood-clotting protein. A common clotting variant raises how much prothrombin you make, modestly increasing the risk of vein clots.

Possible results

No prothrombin variant. You don't carry the common clotting variant that raises prothrombin, so from what this gene shows your blood-clotting protein levels are typical and your clot risk is at baseline.

Higher clot risk. You carry one copy of the common clotting variant that raises prothrombin (a blood-clotting protein) a little, which modestly increases the risk of vein clots. Most carriers never have a clot, but it's worth knowing around surgery, long travel, pregnancy or estrogen-containing birth control.

High clot risk. You have two copies of the clotting variant that raises prothrombin (uncommon), which raises your clotting protein more and increases the risk of vein clots. This is worth discussing with a doctor, especially around surgery, pregnancy or hormone use, where simple precautions help.

Evidence & sources

Across global populations, fewer than 1% of people carry two copies of this variant, and about 98% carry none.

This variant appears in 10 published genetic studies: PubMed 25772935 · PubMed 26908601 · PubMed 28373160 · PubMed 31420334 · PubMed 31676865 · PubMed 35285134 · PubMed 36154123 · PubMed 36777996 · PubMed 39024449 · PubMed 39789286.

Related

Atrial fibrillation · Autoimmune risk (PTPN22 R620W) · Colorectal cancer risk (8q24) · Longevity-associated variant (FOXO3) · Prostate cancer (male) · Type 2 diabetes risk · Venous thromboembolism (clots)