Education :: Machaon Diagnostics

Test Info | Disease Info | Case Studies | Newsletter Sign Up

<< back

Prothrombin (G20210A) Mutation

Factor II, biosynthesized in the liver, is one of the Vitamin K-dependent coagulation factors and is the circulating precursor of thrombin. The Prothrombin (G20210A)
Mutation, often called the Poort Mutation, causes increased plasma prothrombin levels, resulting in increased venous and arterial thrombotic disorders.

The mutation is present in 1.2% to 3% of in people of Caucasians or African descent. It is very rare in the Asian population. It is present in 18% of patients with venous thrombosis.

The relative risk for developing venous thrombosis in people with the Prothrombin Poort mutation is only 1.86 compared to the general population. However, the risk rises dramatically when another pro-thrombotic mutation, such as the Factor V Leiden mutation, is present. The risk also becomes significantly increased with the presence of other factors associated with a hypercoagulable state. The increased risk of a myocardial infarction is four fold in young females who smoke and may go up to 6 fold in the presence of other cardiac risk factors such as obesity, oral contraceptives and the presence of antiphospholipid antibodies.

1. Nguyen A. Prothrombin G20210A polymorphism and thrombophilia. Mayo Clin. Proc 75: 595-604, 2000.
2. Rosendaal FR, Doggen CJ, Zivelin A, et al: Geographic distribution of the 20210 G to A Prothrombin variant. Thromb Haemost 79: 706-708, 1998.
3. Rosendaal FR, Siscovick DS, Schwartz SM.: A common prothombin variant (20210 G to A) increases the risk of myocardial infarction in young women. Blood. 90: 1747-1750, 1997.
4. Doggen CJ, Cats VM, Bertina RM, et al.: Interaction of coagulation defects and cardiovascular risk factors: increased risk of myocardial infarction associated with Factor V Leiden or Prothrombin 20210A. Circulation 97: 1037-1041, 1998.