Factor V Leiden (FVL) is the most common inherited cause of a blood clotting tendency, known as thrombophilia. This genetic variation is often discovered after an individual experiences an abnormal blood clot or through family screening. The primary concern is whether the diagnosis will impact lifespan. For the vast majority of people with Factor V Leiden, the condition does not typically reduce life expectancy, especially when managed with awareness and proactive care.
Understanding the Genetics of Factor V Leiden
Factor V Leiden is a mutation in the F5 gene, which provides instructions for making coagulation factor V protein. This protein helps form a fibrin plug to stop bleeding after an injury. The body has a natural regulatory system to prevent clots from growing too large, primarily relying on Activated Protein C (APC).
The FVL mutation causes a structural change in the factor V protein, making it resistant to inactivation by APC. This mechanism is called APC resistance, meaning the clotting process continues for too long. People inherit one copy of the mutated gene (heterozygous) or two copies (homozygous). The heterozygous form is much more common, resulting in a mixture of normal and mutated factor V protein. The homozygous form carries a substantially higher risk of clot formation.
Direct Impact on Life Expectancy
Clinical evidence shows that the presence of the Factor V Leiden gene itself does not affect overall life expectancy. Studies comparing FVL carriers to the general population find no significant increase in overall mortality. A normal lifespan is expected for most individuals with this genetic variation, particularly those who are aware of their status and take appropriate precautions.
The danger to longevity comes from the complications of an abnormal blood clot, primarily Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). A DVT is a clot, usually in the leg, which can become life-threatening if it travels to the lungs, causing a PE. The risk of developing a first DVT is increased approximately five to seven times for heterozygous carriers compared to the general population.
The absolute risk remains low, as approximately 90% of people with the heterozygous FVL mutation will never experience an abnormal clot. For the rare individuals who are homozygous, the risk is significantly higher, increasing the chance of a first clot by up to 80 times. Even when a blood clot occurs, prompt medical treatment with anticoagulants is usually effective in preventing a fatal outcome, reinforcing that the condition is manageable.
Managing Thrombosis Risk and Living Well
Living well with Factor V Leiden centers on proactive risk reduction and careful management. Individuals without a history of clotting events typically do not require daily, long-term anticoagulant medication based solely on the presence of the gene. Instead, preventative, or prophylactic, anticoagulation is often recommended during periods of high risk.
These high-risk situations include:
- Major surgeries.
- Extended periods of immobilization, such as long-haul travel.
- Pregnancy.
- Use of estrogen-containing birth control pills or hormone replacement therapy.
For long trips, simply moving around the cabin or car every hour, performing leg exercises while seated, and maintaining hydration can significantly reduce risk. Lifestyle adjustments are also integral to management, particularly maintaining a healthy weight and engaging in regular physical activity to promote good circulation. Avoiding smoking is highly advisable, as it damages blood vessels and compounds the clotting risk. Women with FVL should communicate with their healthcare provider about avoiding estrogen-containing birth control pills or hormone replacement therapy, as these medications independently increase the risk of thrombosis. Understanding the symptoms of a potential clot—such as leg swelling, pain, or unexplained shortness of breath—and seeking immediate medical attention is crucial for effective treatment.