Overview

Factor V Leiden is a mutation of one of the clotting factors in the blood called factor V. This mutation can increase your chance of developing abnormal blood clots (thrombophilia), usually in your veins.

Most people with factor V Leiden (FAK-tur five LIDE-n) never develop abnormal clots. But some do develop clots that lead to long-term health problems or become life-threatening.

Both men and women can have factor V Leiden. Women may have an increased tendency to develop blood clots during pregnancy or when taking the hormone estrogen.

If you have factor V Leiden and have developed blood clots, anticoagulant medications can lessen your risk of developing additional blood clots and help you avoid potentially serious complications.

Source: http://www.mayoclinic.com

Symptoms

Most people who have factor V Leiden never develop signs or symptoms. The first indication that you have the disorder may be the development of a blood clot (thrombosis).

Some clots do no damage and disappear on their own. Others can be life-threatening. Symptoms of a blood clot depend on where it forms and whether and where it travels.

A clot in a deep vein

This is known as deep vein thrombosis (DVT). Deep vein thrombosis may not cause any symptoms. If signs and symptoms do occur, they commonly affect your legs, including swelling of your ankles and feet. Other signs and symptoms may include:

• Pain
• Significant swelling
• Redness
• Warmth

A clot closer to the surface of your skin

This is referred to as superficial venous thrombosis, phlebitis or thrombophlebitis. Signs and symptoms usually include:

• Warmth
• Tenderness or pain, often in or around the vein with the blood clot
• Redness

A clot that travels to your lungs

Known as a pulmonary embolism, this occurs when a deep vein clot breaks free and travels through the right side of your heart to your lung, where it blocks blood flow. This can be a life-threatening situation. Signs and symptoms may include:

• Sudden shortness of breath
• Chest pain when breathing in
• A cough that produces bloody or blood-streaked sputum
• Rapid heartbeat (tachycardia)

When to see a doctor

Seek medical attention immediately if you:

• Have signs or symptoms of a pulmonary embolism, such as chest pain or discomfort.
• Have signs or symptoms of deep vein thrombosis, such as leg pain and swelling.

See a doctor if you:

• Have a family history of blood clots or if family members have factor V Leiden. Ask your doctor about the risks and benefits of genetic testing for the disorder.
• Have had one or more blood-clotting incidents without an apparent cause, especially if you're under 50.

Source: http://www.mayoclinic.com

Causes

A blood clot (thrombus) normally forms to stop the bleeding when an artery or vein is damaged, such as when you experience a cut. Clots are formed by chemical reactions between specialized blood cells (platelets) and proteins in your blood (clotting factors). Anti-clotting factors prevent an excessive formation of blood clots.

Normally, factor V is a clotting protein. Anti-clotting proteins break up factor V, keeping it from forming clots when clotting isn't needed.

Factor V Leiden makes it harder for anti-clotting proteins to break up factor V. This keeps factor V in the blood longer and increases the chance of clotting.

If you have factor V Leiden, you inherited either one copy (heterozygous) or, rarely, two copies (homozygous) of the defective gene. Inheriting one copy slightly increases your risk of developing blood clots. Inheriting two copies — one from each parent — significantly increases your risk of developing blood clots.

Source: http://www.mayoclinic.com

Diagnosis

Your doctor will likely suspect factor V Leiden if you've had one or more episodes of thrombosis or pregnancy loss or if you have a strong family history of thrombotic disease. Your doctor can confirm that you have factor V Leiden with a blood test. Two types of tests can be done:

• Activated protein C resistance test. Your blood sample may be tested to determine whether your blood is resistant to activated protein C, one of the anti-clotting proteins that help control factor V. This is known as an activated protein C (APC) resistance assay. If your blood is resistant to activated protein C, you likely have a mutation in the factor V gene.

• Genetic test. A genetic test is done to determine whether you have a factor V gene mutation. It may also be used to confirm the results of the APC resistance test or to determine whether you've inherited one or two copies of the gene mutation.

  If you're taking blood-thinning medications (anticoagulants), you may have only the genetic test. Anticoagulants interfere with the activated protein C resistance test.

Testing babies before or soon after birth isn't recommended. Children who don't have symptoms of clotting problems also don't need screening. Blood clots are rare, even in children with factor V Leiden. Testing isn't recommended until adulthood.

When your child is an adult, he or she will be better able to fully understand the risks and benefits associated with genetic testing. Chances are good that your child may never have any signs or symptoms related to factor V Leiden.

Source: http://www.mayoclinic.com

Complications

Factor V Leiden can be associated with a variety of serious and potentially serious clotting complications, including:

• Pregnancy complications. Most women with factor V Leiden have normal pregnancies. But the mutation has been linked with an increased risk of miscarriage and possibly other complications during pregnancy, including pregnancy-induced high blood pressure (preeclampsia), slow fetal growth and early separation of the placenta from the uterine wall (placental abruption). If you're a pregnant woman with factor V Leiden, be sure your doctor monitors you carefully throughout your pregnancy.
• Deep vein thrombosis (DVT). People with factor V Leiden have an increased risk of developing deep vein thrombosis compared with someone without the mutation, though the overall risk of developing deep vein thrombosis is still low.
• Pulmonary embolism. Deep vein thrombosis puts you at risk of a clot breaking off and traveling to your lungs or, rarely, your brain. A pulmonary embolism can be fatal. It's important to watch for signs and symptoms of a pulmonary embolism, such as shortness of breath or chest pain, and to seek prompt medical attention.

Lifestyle and home remedies

If you have factor V Leiden, avoiding certain situations might help reduce your risk of developing blood clots. These include:

• Uninterrupted long car or airline trips. When your legs remain still for long periods — more than two hours — your calf muscles don't contract, which normally helps blood circulate.

  If you can, try to move around whenever possible on a plane. Drink extra water to prevent dehydration, and avoid alcohol. On a car trip, take periodic breaks and walk around.

  If you sit for long periods of time for any reason, get up periodically and stretch your legs.

• Prolonged bed rest, such as during a long illness, or paralysis. Your doctor may suggest the use of compression stockings to keep the blood in your legs moving.
• Injury or surgery. Injury to your veins or surgery can slow blood flow, increasing the risk of blood clots. General anesthetics used during surgery can dilate your veins, which can increase the risk of blood pooling and then clotting. Let your doctor know that you have factor V Leiden.
• Oral contraceptives or estrogen replacement therapy. Because these medications can increase the risk of blood clots on their own, be sure to discuss the risks and the benefits of estrogen-containing medications with your doctor if you have factor V Leiden.
• Being overweight or obese. Being overweight increases the pressure in the veins in your pelvis and legs. Losing weight can lower your risk.
• Smoking. Smoking affects blood clotting and circulation. If you're a smoker, take steps to quit.

Donating blood

One situation you don't have to avoid if you have factor V Leiden is donating blood. People with factor V Leiden can usually donate blood if interested in doing so.

If you're taking blood-thinning medications, you can't donate blood until those medications are fully out of your system. If you've taken blood thinners, check with your doctor before donating blood.

Preventing excessive bleeding

If your factor V Leiden requires you to take anticoagulant medication, here are some steps that might help you prevent injury and avoid excessive bleeding:

• Avoid playing contact sports or engaging in other activities that could result in physical injury. Regular noncontact exercise, such as walking or swimming, is still recommended for good health.
• Use a soft toothbrush and waxed floss.
• Avoid shaving cuts by using an electric razor.
• Be cautious with household tasks involving knives, scissors and other sharp tools.

Source: http://www.mayoclinic.com

Risk factors

A family history of factor V Leiden increases your risk of inheriting the disorder. The disorder is most common in people who are white and of European descent.

Source: http://www.mayoclinic.com