The factor II prothrombin G to A 20210 gene mutation was recently described as a risk factor for thromboembolism. It is present in up to 2.3% of individuals (as determined in a population-based case control study) and 1% of healthy controls. The mutation is found in up to 10% of patients who are either heterozygous or homozygous for the factor V Leiden mutation, suggesting that patients who harbor a factor V Leiden mutation should also be screened for the G to A 20210 mutation. The mutation also increases the risk of myocardial infarction in young women.

The factor II prothrombin G to A 20210 gene mutation can be diagnosed using a simple PCR genetic assay. It is generally performed in conjunction with the factor V Leiden assay.

Genetic counseling is available by calling the Allina Molecular Diagnostics Lab. The Molecular Diagnostic Lab's team of certified genetic counselors will help with any questions about the test or issues for families.

REFERENCES:

1. Poort SR, Rosendaal FR, Reitsma PH, Bertina RM. A common variation in the 3’untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis. Blood 88:3698-3703, 1998.
2. Howard, TE, Marusa M, Boisza J et al. The prothrombin gene 3’ untranslated region mutation is frequently associated with factor V Leiden in thrombophilic patients and show ethnic-specific variation in allele frequency. Letter to the Editor. Blood 91:1092, 1998.
3. Rosendaal FR, Siscovick DS, Schwartz SM et al. A common prothrombin variant (20210 G to A) increases the risk of myocardial infarction in young women. Blood 90:1747-1750, 1997.