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Encyclopedia > Factor V Leiden

Factor V Leiden (sometimes Factor VLeiden) is the name given to a variant of human factor V that causes a hypercoagulability disorder. In this disorder the Leiden variant of factor V, cannot be inactivated by activated protein C. Factor V Leiden is the most common hereditary hypercoagulability disorder amongst Eurasians. It is named after the city Leiden (The Netherlands), where it was first identified in 1994 by Prof R. Bertina et al. Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. ... Thrombophilia is the propensity to develop thrombosis (blood clots) due to an abnormality in the system of coagulation. ... Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. ... Protein C is a major physiological anticoagulant. ... For the scientific journal Heredity see Heredity (journal) Heredity (the adjective is hereditary) is the transfer of characters from parent to offspring, either through their genes or through the social institution called inheritance (for example, a title of nobility is passed from individual to individual according to relevant customs and... A disease or medical condition is an abnormality of the body or mind that causes discomfort, dysfunction, distress, or death to the person afflicted or those in contact with the person. ... Map showing the location of Avar Khaganate, c. ... Leyden redirects here. ... Motto: Je Maintiendrai (Dutch: Ik zal handhaven, English: I Shall Uphold) Anthem: Wilhelmus van Nassouwe Capital Amsterdam1 Largest city Amsterdam Official language(s) Dutch2 Government Parliamentary democracy Constitutional monarchy  - Queen Beatrix  - Prime minister Jan Peter Balkenende Independence Eighty Years War   - Declared July 26, 1581   - Recognised January 30, 1648 (by Spain... 1994 (MCMXCIV) was a common year starting on Saturday of the Gregorian calendar, and was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by United Nations. ...

Contents

Pathophysiology

In the normal person, factor V functions as a cofactor to allow factor X to generate the active form of an enzyme called thrombin. Thrombin in turn cleaves fibrinogen to fibrin, which polymerizes to form the dense meshwork that makes up the majority of a clot. Activated protein C (aPC) is a natural anticoagulant that acts to limit the extent of clotting by cleaving and degrading factor V. A cofactor is the following: In mathematics a cofactor is the minor of an element of a square matrix. ... Factor X, also known by the eponym Stuart-Prower factor or as thrombokinase, is an enzyme ( EC 3. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Fibrin is a protein involved in the clotting of blood. ... Fibrin is a protein involved in the clotting of blood. ... Coagulation is the thickening or congealing of any liquid into solid clots. ... Protein C is a major physiological anticoagulant. ... An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ...


Factor V Leiden is an autosomal dominant condition in which the coagulation factor cannot be destroyed by aPC. Mutation of the gene encoding factor V—a single nucleotide substitution of adenine for guanine—changes the protein's 506th amino acid from arginine to glutamine . Since this amino acid is normally the cleavage site for aPC, the mutation prevents efficient inactivation of factor V. When factor V remains active, it facilitates overproduction of thrombin leading to excess fibrin generation and excess clotting. An autosomal dominant gene is one that occurs on an autosomal (non-sex determining) chromosome. ... In biology, mutations are changes to the genetic material (either DNA or RNA). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... Adenine is one of the two purine nucleobases used in forming nucleotides of the nucleic acids DNA and RNA. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. ... Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA; the others being adenine, cytosine, thymine, and uracil. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The general structure of an α-amino acid molecule, with the amine group on the left and the carboxyl group on the right. ... Arginine (symbol Arg or R) is an α-amino acid. ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ...


The excessive clotting that occurs in this disorder is almost always restricted to the veins, where the clotting may cause a deep vein thrombosis (DVT). If the venous clots break off, these clots can travel through the heart to the lung, where they block a pulmonary blood vessel and cause a pulmonary embolism. Women with the disorder have an increased risk of miscarriage and stillbirth. This disorder does not increase the formation of clots in arteries that can lead to stroke or heart attack, though a "mini-stroke" know as a transient ischemic attack may occur. In biology, a vein is a blood vessel which carries blood toward the heart. ... Deep-vein thrombosis, also known as deep-venous thrombosis or DVT, is the formation of a blood clot (thrombus) in a deep vein. ... The heart and lungs, from an older edition of Grays Anatomy. ... The lungs flank the heart and great vessels in the chest cavity. ... The pulmonary blood vessels are those which carry blood from and to the lungs. ... A stroke, also known as cerebrovascular accident (CVA),[1] is an acute neurological injury in which the blood supply to a part of the brain is interrupted. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... Transient ischemic attacks (TIA) are caused by temporary disturbance of blood supply to a restricted area of brain and cause recurrent and brief (less than 24 hours) neurologic dysfunctions. ...


Epidemiology

Studies have found that about 5% of caucasians in North America have factor V Leiden. The disease is less common in Hispanics and African-Americans and is extremely rare in people of Asian descent.


Up to 30% of patients who present with deep vein thrombosis (DVT) or pulmonary embolism have this condition. Factor V Leiden doubles the risk that a person will have a DVT during their life, but it is unclear whether these individuals are at increased risk for recurrent a venous thrombosis. While only 1% of people with factor V Leiden have two copies of the defective gene, these homozygous individuals have a more severe clinical condition. The presence of acquired risk factors for venous thrombosis -- including smoking, oral contraceptive use, and recent surgery -- further increase the chance that an individual with the factor V Leiden mutation. Deep-vein thrombosis, also known as deep-venous thrombosis or DVT, is the formation of a blood clot (thrombus) in a deep vein. ... Homozygote cells are diploid or polyploid and have the same alleles at a locus (position) on homologous chromosomes. ... Look up Smoking in Wiktionary, the free dictionary. ... Oral contraceptives, often referred to as the Pill, are chemicals taken by mouth to inhibit normal fertility. ... A cardiothoracic surgeon performs a mitral valve replacement at the Fitzsimons Army Medical Center. ...


Women with Factor V Leiden (FVL) have a substantially increased risk of clotting in pregnancy (and on estrogen containing birth control pills or hormone replacement) in the form of DVT (deep vein thrombosis, sometimes known as "milk leg") and pulmonary embolism. They also have an increased risk of preeclampsia, as well as miscarriage and stillbirth due to clotting in the placenta, umbilical cord, or the fetus (fetal clotting may depend on whether the baby has inherited the gene). Note that many, many of these women go through one or more pregnancies with no difficulties, while others may miscarry over and over again, and still others may develop clots within weeks of becoming pregnant.


Diagnosis

Suspicion of factor V Leiden being the cause for any thrombotic event should be considered in any white patient below the age of 45, or in any person with a family history of venous thrombosis.


This disease can be diagnosed by watching the aPTT (the time it takes for blood to clot) as activated protein C is added. With a normal patient, adding aPC increases the APTT. In patients with factor V Leiden, adding aPC will barely affect the time it takes for blood to clot. The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is a commonly performed test for the system of coagulation, especially its intrinsic pathway. ...


There is also a simple genetic test that can be done for this disorder. The mutation (a 1691G→A substitution) removes a cleavage site of the restriction endonuclease MnlI, so simple PCR, treatment with MnlI, and then DNA electrophoresis will give a quick diagnosis. A restriction enzyme (or restriction endonuclease) is an enzyme that cuts double-stranded DNA. The enzyme makes two incisions, one through each of the phosphate backbones of the double helix without damaging the bases. ... Wikipedia does not yet have an article with this exact name. ... Digital printout of an agarose gel electrophoresis of cat-insert plasmid DNA DNA electrophoresis is an analytical technique used to separate DNA fragments by size. ...


References

  • Bertina RM, Koeleman BP, Koster T, Rosendaal FR, Dirven RJ, de Ronde H, van der Velden PA, Reitsma PH. Mutation in blood coagulation factor V associated with resistance to activated protein C. Nature 1994;369:64-7. PMID 8164741.

  Results from FactBites:
 
Factor V Leiden - Wikipedia, the free encyclopedia (347 words)
Factor V Leiden is the most common hereditary hypercoagulability clotting disorder amongst Eurasians, possibly affecting up to 5% of the population of the U.S. It is named after the city Leiden (The Netherlands), where it was first identified in 1994 by Prof R. Bertina et al.
It is an autosomal dominant condition in which the coagulation factor has a mutation and cannot be destroyed by activated protein C (aPC).
Suspicion of Factor V Leiden being the cause for any thrombotic event should be considered in any white patient below the age of 45, or in any person with a family history of thrombosis.
  More results at FactBites »

 
 

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