Factor V Leiden

What is Factor V Leiden?

Factor V Leiden is a type of blood disorder. This blood disorder is inherited genetically and specifically affects a substance in the blood responsible for clotting. This clotting substance is known as a clotting factor (which is a type of protein in the blood), specifically referred to as factor V. When a person suffers from Factor V Leiden, it means that their factor V has mutated and cannot function properly.

A person with Factor V Leiden is at an increased risk of developing blood clots that are abnormal and potentially dangerous. This blood clotting disorder is inherited genetically and can be inherited from one or both of the person’s parents.

Factor V is a normal clotting factor in the body, but when a person has Factor V Leiden instead of regular factor V, it is more difficult to stop it from causing the blood to clot. When a person inherits this condition from one parent, the likelihood that they will develop a blood clot is increased but not a great deal. However, if they inherit the condition from both parents, the chance that they will develop blood clots in their lifetime increases significantly.

What are the Symptoms of Factor V Leiden?

Factor V Leiden usually goes undetected until the person develops a blood clot. However, not all blood clots are noticeable or cause any significant risks when they develop. Since the clot can go undetected a person may never know that they have Factor V Leiden.

Symptoms include

Blood clots can occur in many different areas of the body. If the clot occurs close to the surface of the skin, the area may be tender, warm or red. Deep vein thrombosis, when a clot forms deeper inside the body can also cause pain, swelling, and redness. Some blood clots can break free and travel to the lungs or elsewhere in the body and can be dangerous and life-threatening.

Factor V Leiden Causes

Factor V Leiden is a genetic disorder caused by a specific genetic mutation in the Factor V gene. Factor V is a clotting protein, meaning that its job is to clot blood when necessary. Generally, anti-clotting proteins work to prevent Factor V from clotting when it is not necessary, keeping blood flowing smoothly and preventing dangerous clots. Factor V Leiden, however, makes it much more difficult for anti-clotting proteins to do their job, leading to a greater risk of blood clots.

There is a genetic component to Factor V Leiden. People with a family history of Factor V Leiden are at much greater risk to have it themselves, and it is more common in people of European descent than in other ethnic groups.

How is Factor V Leiden Treated?

While Factor V Leiden cannot be cured, there are treatment options if a person has a history of blood clots and to prevent blood clots.

Treatment includes

Blood thinners are the most common form of treatment for the condition. If you have had blood clots in the past, you may be prescribed a regular blood thinner to take all the time. However, if you have not had blood clots in the past, your doctor may only recommend that you take blood thinners in specific circumstances where your risk increases. Pregnant women or women who take birth control medications are also at increased risk of blood clots if they have Factor V Leiden, and may need monitoring and treatment to prevent them.

Factor V Leiden Prevention

Only about 5% of people with Factor V Leiden develop a dangerous blood clot before the age of 65, but that doesn’t mean an individual shouldn’t take every preventative step to reduce their risk. One of the simplest but most important preventative measures a person can take is simply to keep moving. When sitting still for a long period of time (two hours or more), blood circulates much slower through the legs, leading to an increased risk of a blood clot. Standing to stretch every hour keeps your circulation rate up. Similarly, prolonged bed rest or illness can have the same effect, as the body is unable to exercise. Compression stockings may be recommended by your doctor in order to keep circulation up while on bed rest.

Oral contraceptives and estrogen replacement therapy can both increase the chances of blood clots on their own, so people with Factor V Leiden should talk with their doctor about their specific risk factors when using these medications.

Finally, maintaining a healthy diet and regular exercise will lower one’s chance of a blood clot caused by Factor V Leiden. Being overweight or obese increases the pressure on a person’s pelvic veins, which also increases the risk of obtaining a blood clot. Losing weight can help lower one’s risk.

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Last Reviewed:
September 20, 2016
Last Updated:
December 21, 2017