About Us

Factor V Leiden is the most common hereditary blood coagualtion disorder in the United States. It is present in 5% of the Caucasian population and 1.2% of the African American population.

Factor V Leiden increases the risk of venous thrombosis 3-8 fold for heterozygous (one damaged gene inherited) and substantially more, 30-140 fold, for homozygous (two damaged genes inherited) individuals.

The prothrombin 20210 mutation is the second most common inherited clotting abnormality. It is more common than protein S and C deficiency and Antithrombin deficiency combined; 2% of the general population is heterozygous. It is only a mild risk factor for clots, but together with other risk factors (such as oral contraceptives, surgery, trauma, high blood pressure, obesity, smoking, etc) or combined with other clotting disorders (like Factor V Leiden), the risk of clotting increases dramatically.

Factor V Leiden can be associated with the following complications:

• Venous Thrombosis blood clots in veins, such as:
  • Deep vein thrombosis (DVT), veins in arms and legs
  • Superficial thrombophlebitis
  • Sinus vein thrombosis, veins around the brain
  • Mesenteric vein thrombosis, intestinal veins
  • Budd-Chiari syndrome, liver veins
• Pulmonary Embolism (PE), blood clots in the lungs
• Arterial clots (stroke, heart attack) in selected patients (some smokers)
• Possibly with stillbirth or recurrent unexplained miscarriage
• Preeclampsia and/or eclampsia (toxemia while pregnant)

If you have experienced any of these complications, you may have Factor V Leiden. However, many people with Factor V Leiden remain completely healthy throughout their lives.

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Many of us with Factor V Leiden have had strokes and transient ischemic attacks (TIAs). An unproven association is gall bladder disfunction, but many of us with thrombophilia have had trouble with or have had our gall bladders removed.

A simple blood test, available since 1993, can test for Factor V Leiden. For more information on other clotting test that you can have done or for answers to questions about thrombophilia, please select the links above or below. The Recently Diagnosed section lists several blood tests that you can have done to determine if you have a clotting disorder.