Factor V Leiden – Symptoms and Causes
Overview
Factor V Leiden is a genetic mutation affecting a blood clotting factor. People with this mutation have an increased risk of developing abnormal blood clots, particularly in the legs or lungs.
The condition affects both men and women, though women may face higher risks during pregnancy or when taking estrogen-containing medications.
Most individuals with Factor V Leiden never experience clotting problems. However, for those who do develop clots, the condition can lead to serious health complications or even become life-threatening if not properly managed.
For patients who have already experienced blood clots, doctors typically prescribe anticoagulant medications (blood thinners). These medications help reduce the risk of developing additional clots and prevent potential complications.
The condition is named after the specific clotting factor affected (Factor V) and the city of Leiden in the Netherlands, where researchers first identified the mutation.
Warning Signs
Blood Clot in a Deep Vein
When a blood clot forms in a deep vein, known as deep vein thrombosis (DVT), it typically develops in the legs. Some people may not notice any symptoms at all. However, if symptoms do appear, they often include:
- Pain in the affected area
- Swelling of the leg or arm
- Redness of the skin
- Warmth around the affected area
These symptoms might develop slowly or suddenly. The affected limb may feel heavy or tender when you touch it.
Blood Clot That Moves to Your Lungs
If part of a blood clot breaks free and travels to your lungs, it’s called a pulmonary embolism. This is a serious condition that needs immediate medical care. Watch for these warning signs:
- Sudden breathing problems
- Sharp chest pain, especially when taking a breath
- Coughing that may bring up blood
- Rapid heartbeat
Other possible symptoms include feeling dizzy or lightheaded, sweating more than usual, and having a bluish tint to your lips or nails.
When to Get Medical Help
Don’t wait if you notice signs of either a deep vein blood clot or a pulmonary embolism. These conditions can be life-threatening and require prompt treatment.
Call emergency services or go to the nearest emergency room if you experience sudden chest pain, difficulty breathing, or cough up blood. For leg pain, swelling, and redness that develops without injury, contact your doctor right away.
Causes
Factor V Leiden occurs due to genetic inheritance. When someone has this condition, they have received a defective gene that affects blood clotting.
People can inherit either:
- One copy of the defective gene – This causes a slight increase in blood clot risk.
- Two copies of the defective gene – This happens when both parents pass down the defective gene, creating a significantly higher risk of blood clots.
The presence of this genetic mutation changes how the body regulates clotting, making blood more likely to form clots inappropriately.
Risk Factors
Family history plays a key role in factor V Leiden risk. This condition appears most frequently in white people with European ancestry.
People who inherit the mutation from one parent have about a 5% chance of developing an abnormal blood clot by age 65. Several factors can increase this risk:
- Inheriting two faulty genes from both parents significantly raises the risk of abnormal clots.
- Long periods without movement, such as during lengthy flights, can increase the chance of leg clots.
- Exposure to estrogens through birth control pills, hormone therapy, or pregnancy.
- Recent surgeries or injuries like broken bones.
- Blood types A, B, or AB carry a higher risk compared to type O.
The combination of factor V Leiden with any of these risk factors can further increase a person’s chance of developing blood clots. Being aware of these risk factors helps doctors determine who might need preventive treatment.
Complications
Factor V Leiden increases the risk of developing dangerous blood clots. These clots commonly form in the deep veins of the legs. This condition is called deep vein thrombosis (DVT).
If a clot breaks free, it can travel to the lungs. This can cause a pulmonary embolism, which can be life-threatening if not treated promptly.
