Prothrombin G20210A
One copy of the Prothrombin G20210A variant detected (heterozygous).
You have one copy of the Prothrombin G20210A DNA change.
Associated with roughly a 2–3× increased lifetime risk of venous thromboembolism. Most carriers are asymptomatic.
Your lifetime risk of a dangerous blood clot is roughly 2 to 3 times the average. Most people with one copy never actually experience a clot.
What this means
The G20210A variant sits in the 3' untranslated region of the prothrombin (factor II) gene. It leads to elevated circulating prothrombin and a modest pro-thrombotic tendency. Like Factor V Leiden, it is much more consequential in combination with other risk factors than alone.
This DNA change sits in a control region of the prothrombin gene (also called factor II). It leads to higher levels of prothrombin — a key clotting protein — in your blood, which gently tips your body towards clotting. Like Factor V Leiden, it matters much more when combined with other risk factors (surgery, pregnancy, hormonal contraceptives, long flights) than on its own.
Caveats
- Most carriers never experience a clotting event.
- Combining this with Factor V Leiden or oestrogen-containing contraceptives meaningfully changes the risk picture.
- Anticoagulation isn't routinely recommended for asymptomatic carriers.
Populations
- About 2% allele frequency in European populations; much rarer elsewhere