Question: What is (are) Factor V Leiden thrombophilia ?
Answer: Factor V Leiden thrombophilia is an inherited disorder that results in an increased risk of developing abnormal blood clots. Factor V Leiden is the name of a specific gene mutation in the F5 gene. This gene plays a critical role in the normal formation of blood clots in response to an injury. People can inherit one or two copies of the factor V Leiden gene mutation. Those who inherit one copy are called heterozygotes. People who inherit two copies of the mutation, one from each parent, are called homozygotes. Having the factor V Leiden mutation increases your risk for developing a clot in your legs called a deep venous thrombosis (DVT). It also increases your risk of developing a clot that travels through the bloodstream and lodges in the lungs, called a pulmonary embolism (PE).
Source: GARD

Question: What are the symptoms of Factor V Leiden thrombophilia ?
Answer: What are the signs and symptoms of factor V Leiden thrombophilia? Individuals affected by factor V Leiden thrombophilia have an increased risk of developing blood clots. The severity of factor V Leiden thrombophilia is extremely variable. Many individuals with the factor V Leiden allele never develop a blood clot. Although most individuals with factor V thrombophilia do not experience their first thrombotic event until adulthood, some have recurrent thromboembolism before age 30 years. The chance a person will develop a blood clot is affected by the number of factor V Leiden mutations, the presence of coexisting genetic abnormalities, and non-genetic risk factors. Non-genetic risk factors include surgery, long periods of not moving (like sitting on a long airplane ride), birth control pills and other female hormones, childbirth within the last 6 months, and traumas or fractures. Individuals who inherit one copy of the factor V Leiden mutation have a fourfold to eightfold increase in the chance of developing a clot. Homozygotes (people who inherit two factor V Leiden mutations) may have up to 80 times the usual risk of developing a blood clot. Considering that the risk of developing an abnormal blood clot averages about 1 in 1,000 per year in the general population, the presence of one copy of the factor V Leiden mutation increases that risk to 4 to 8 in 1,000, and having two copies of the mutation may raise the risk as high as 80 in 1,000. People with factor V Leiden have an increased chance of having a blood clot that forms in large veins in the legs (deep venous thrombosis, or DVT) or a clot that travels through the bloodstream and lodges in the lungs (pulmonary embolism, or PE). Symptoms of deep vein thrombosis usually include leg pain, tenderness, swelling, increased warmth or redness in one leg. The symptoms of pulmonary embolism usually include cough, chest pain, shortness of breath or rapid heartbeat or breathing. To learn more about the symptoms of DVT and PE, click here.
Source: GARD

Question: What causes Factor V Leiden thrombophilia ?
Answer: What causes factor V Leiden thrombophilia? Factor V Leiden thrombophilia is caused by a specific mutation in the Factor V gene. Factor V plays a critical role in the formation of blood clots in response to injury. Genes are our bodys instructions for making proteins. The factor V gene instructs the body how to make a protein called coagulation factor V. Coagulation factor V is involved in a series of chemical reactions that hold blood clots together. A molecule called activated protein C (APC) prevents blood clots from growing too large by inactivating factor V.
Source: GARD

Question: How to diagnose Factor V Leiden thrombophilia ?
Answer: How is factor V Leiden thrombophilia diagnosed? No clinical features (signs and/or symptoms) are specific for factor V Leiden thrombophilia. The diagnosis of factor V Leiden thrombophilia requires a coagulation screening test or DNA analysis of F5, the gene for factor V, to identify the specific mutation that causes this condition. The APC (activated protein C) resistance assay, a coagulation screening test, measures the anticoagulant response to APC. This screening test has a sensitivity and specificity for factor V Leiden approaching 100%. The sensitivity of a test is a measure of the test's ability to detect a positive result when someone has the condition, while the specificity is a measure of the test's ability to identify negative results.Targeted mutation analysis (a type of DNA test) of the F5 gene for the Leiden mutation is considered definitive and has a mutation detection frequency of approximately 100%. This means that approximately all individuals who have the factor V Leiden mutation will be detected by this genetic test. It is generally recommended that individuals who test positive by another means should then have the DNA test both for confirmation and to distinguish heterozygotes (individuals with a mutation in one copy of the gene) from homozygotes (individuals with mutations in both copies of the gene).
Source: GARD