Factor V Leiden is an inherited disorder where mutation of one of the clotting factors in the blood increases the chance of developing abnormal blood clots or thrombus, most commonly in your legs or lungs resulting in a condition called thrombophilia.

Although most people with factor V Leiden hardly develop abnormal clots, but those who do, these abnormal clots can often lead to long-term health issues or become fatal in nature. The incidence of having this disorder is same in both men and women. Women who carry the Factor V Leiden mutation, often show an increased risk of developing blood clots during pregnancy or while taking the hormone estrogen.

Also Read: World Thrombosis Day 2020: Know About The Different Types Of Thrombosis

This genetic disorder often puts people in an increased risk of two conditions:

Deep Vein Thrombosis (DVT): It is a chronic medical condition, wherein the blood clot or thrombus forms in one or more of the veins located deep inside the body, usually in the veins of the pelvis, thigh or lower leg. They often happen if someone is sitting for a long duration, especially during a flight.

Also Read: Deep Vein Thrombosis: Causes, Symptoms And Treatment

Pulmonary Embolism (PE): This condition arises when the blood clot that has happened somewhere travels through the blood stream and gets lodged into the lungs. It can block the flow of blood in the lungs, limiting the oxygen supply to the various other organs. If the clot is large, it can be fatal.


The Factor V Leiden syndrome mainly happens due to genetic factors i.e., changes or mutation a person is born with. People are often born with one or 2 copies of the defective gene from either or both parents. While presence of one copy of the mutated change slightly increases the risk of developing blood clots, having 2 copies of it aggravated the risk to an extreme condition.

Risk Factors

Certain causative factors that increase the risk of developing Factor V Leiden syndrome includes:

Ethnicity: This disorder is more common in white people of European descent.

Two Faulty Genes: Inheriting the genetic mutation from both the parents significantly makes one more prone to developing abnormal blood clots.

Immobility: Extended periods of immobility, especially of the legs such as sitting during a long airplane flight, aggravates the risk of leg clots.

Estrogens: People who are taking birth control pills, hormone replacement therapy or are pregnant are more likely to develop blood clots.

Surgeries or Injuries: People who have undergone any surgeries or had an injury such as broken bones have an increased risk of abnormal blood clots.

Non-O Blood Type: Abnormal blood clots are more commonly noticed in people who have blood types of A, B or AB compared with those with blood type O.


Factor V Leiden disorder itself does not show any characteristic symptom, but since some of the abnormal blood clots happen in the deep vein or gets dislodged and settles within the lungs, it leads to some common symptoms. These include:

In case of DVT:

  • Swelling
  • Pain and tenderness
  • Heaviness of the affected part
  • Warmth of the skin
  • Vivid red discoloration
  • Purple or “bluish” discoloration of the skin
  • Veins that look large than usual

In case of P.E:

  • Sudden shortness of breath
  • Coughing up blood or blood-streaked sputum
  • Sharp chest pain
  • Rapid heartbeat and palpitations (i.e., tachycardia)
  • Fainting or dizziness
  • Very low blood pressure

Diagnosis And Treatment

If you notice any of the above-mentioned signs and symptoms, do consult a doctor immediately to avoid complications. The doctor usually does a thorough physical check-up, acknowledges the patient’s genetic history and medical history followed by a special blood test that detects the presence of mutation.


Since Factor V Leiden is a genetic disorder, it does not have any particular cure. A normal blood clot does not require any specific medication. The main goal of the doctor is to lower the chance of having risky blood clots while still letting the body make the clots that it is truly essential. The doctor chiefly recommends to keep a track of the critical symptoms.

But if you already have the symptom, ensure that you let your treating doctor know about it, if you are suddenly going for a surgery, are pregnant or planning for a pregnancy. In such cases, the doctor mainly suggests for the following:

  • Blood-thinning medications or anti-coagulants like Heparin or Warfarin
  • Leg wraps that inflate and deflate the legs to keep the blood moving
  • Compression stockings
  • Going for walks soon after surgery