Prothrombin 20210 Defect

A. Prothrombin is also known as Factor II

B. The conversion of Factor X to Xa changes prothrombin into its active form, thrombin, which then accelerates the formation of fibrin.

A. History - As with Factor V Leiden, Dutch scientists were investigating plasma samples from patients who were clearly thrombophilic yet did not have the known thrombophilic defects.

B. They discovered an abnormal prothrombin (Factor II) molecule, where there is a G to A point mutation at position 20210.

C. Like the Factor V Leiden mutation, this mutation in prothrombin leaves the molecule with normal procoagulant function but interferes with its inhibition (which is currently unclear).

D. This entity explains perhaps 10-15% of inherited thrombophilia. However, this mutation may be found in 1-3% of normal persons

A. Increased risk of venous thrombosis and pulmonary embolism. Venous thrombosis occurs most frequently in the deep veins of the lower extremities.

B. Thrombotic events begin in mid-late teenage years.

C. Mesenteric veins, inferior vena cava, renal veins are all susceptible.

D. Cerebral vein thrombosis can occur.

E. May be precipitated by provocations such as surgery, trauma, pregnancy, oral contraceptive (OCP) use, or infection.

F. Arterial thrombotic events are not increased.

A. Diagnosis of the Prothrombin 20210 mutation is made by PCR analysis of the DNA from patients suspected of having thrombophilia.

B. Treatment of Prothrombin 20210 Defect