Hemophilia Basics

Coagulation disorders - a large group of conditions in which a person experiences excessive bleeding or clotting.

Chromatography - A purification process used to separate proteins or other biological compounds based on their individual physical or chemical properties.

Chromosome - The threadlike structures inside human cells that contain genetic information. Every human being has 23 pairs of chromosomes.

Clotting factors - These are important proteins needed to form blood clots.

Creutzfeldt-Jakob Disease (CJD) - Human prion-related disease causing serious neurological damage. Classic CJD and new variant CJD (vCJD) are separate conditions. However, both diseases could be transmitted in blood products and are rapidly progressive and always fatal.

Cryoprecipitate - Form of Factor VIII-concentrated plasma. It is no longer used as the current standard of treatment in the United States.

Desmopressin Acetate (also DDAVP or Stimate®) - synthetic hormone used to treat people with mild hemophilia or von Willebrand disease by increasing factor VIII levels or vW factor levels in blood.

Diluent - A liquid, typically water, used to dissolve (reconstitute) a powdered medicinal product, such as clotting factor.

Factor Assay - Specialized lab test used to determine the level of circulating factor VIII or IX in a person's body.

Factor Deficiencies - Rare disorders identified by the particular deficient or missing clotting factor in a person's body. These conditions include: Factor I, II, V, VII, VIII, IX, X, XI, XII, and XIII.

Gene - Section of DNA, the chemical code of the body that controls production of a protein.

Gene Therapy - Method of replacing, manipulating or supplementing a dysfunctional gene with a functioning one. This evolving technique is currently being researched in several inherited diseases, including hemophilia. There is hope that gene therapy will lead to better treatments, and eventually cures.

Half-life - The average time required for the body to consume hald the amount of a drug, such as clotting factor. The actual half-life among individual patients and products can vary widely.

Hemoglobin - Protein that carries oxygen and carbon dioxide in red blood cells.

Hematologist - Physician who specializes in blood disorders.

Hemophilia - Bleeding disorder in which a specific clotting factor protein, namely factor VIII or IX, is missing or does not function normally.

Hemophilia A - Deficiency or absence of factor VIII.

Hemophilia B - deficiency or absence of factor IX.

Mild Hemophilia - Categorical term used to describe someone with a factor VIII or IX level ranging from 5% to 40% of normal blood levels.

Moderate Hemophilia - Categorical term used to describe someone with a factor VIII or IX level ranging from 1% to 5% of normal blood levels.

Severe Hemophilia - Categorical term used to describe someone with a factor VIII or IX level below 1% of normal blood levels.

Hemophilia Treatment Centers (HTCs) - Group of federally-funded hospitals that specialize in treating patients with coagulation disorders. Team with a hematologist, nurse, social worker, and physical therapist to deliver comprehensive care to patients and families.

Hemostasis - Process by which the body stops bleeding. It is the stoppage of blood flow through vessels or organs.

Hepatitis - Group of viruses that can lead to infection and inflammation of the liver.

Hereditary disease - A condition that is genetically passed down to one's offspring.

HIV (Human Immunodeficiency Virus) - The virus that causes AIDS.

Infusion - Means of delivering treatment.

Continuous infusion - Procedure of steadily infusing clotting factor concentrate in order to maintain hemostasis.

Inheritance - Biological process of transmitting certain characteristics or conditions from parents to offspring.

Inhibitor - Antibody that develops in direct response to infused clotting factor rendering the treatment ineffective.

International Unit (IU) - A standardized measure of the activity (functional amount) of a substance. The IU determines the potency of the product. One IU of human factor VIII or IX, as defined by the World Health Organization, is approximately equal to the amount of factor VIII or IX in 1.0 milliliter (ml) of pooled human plasma. not all factors have an international standard.

Monoclonal Antibody - Antibodies are specific immune system proteins made by white blood cells to neutralize harmful germs or other foreign substances. Monoclonal antibodies are a group of identical antibodies that attach to a very specific part of their targets. Monoclonal antibodies that target factor can be used to bind factor and separate it from plasma or, with recombinant products, from cell culture medium.

Nanofiltration - A purification process in which protein solutions are passed through filters that are small enough to remove viruses while allowing therapeutic proteins to pass through.

Orthopedic - Term having to do with the bones, the skeleton or associated structures.

Platelets - Tiny "plate-like" components of blood that help to seal off injured blood vessels and stop bleeding.

Plasma - The clear yellowish fluid portion of the blood, lymph, or intramuscular fluid in which cells are suspended. Plasma contains water, salts, enzymes, hormones, nutrients, cellular waste, and proteins such as clotting factors.

Recovered Plasma - Plasma obtained as a by-product of a whole blood donation. The volume of a unit of recovered plasma is typically 200 to 250 ml.

Source Plasma - Plasma collected by plasmapheresis and used as a base material for the further manufacturing of medicinal products. The volume of a unit of source plasma is typically 500 to 800 ml.

Plasmapheresis - A blood collection process during which whole blood is removed from a donor, while red blood cells are simultaneously separated from the plasma and returned to the donor. The plasma is retained for use in preparing medicinal products such as clotting factor concentrates or albumin.

Prophylaxis - Treatment regimen aimed at preventing bleeding episodes.

Primary prophylaxis - Method of regularly scheduled treatments to prevent bleeding episodes before they occur, used to prevent long-term damage to joints.

Purity - The proportion of factor relative to other proteins present in concentrates. Often expressed in the number of international units (IUs) of factor per milligram (mg) or protein. Concentrates are often unofficially identified as “ultra-high,” “high,” “intermediate” and “low.” Purity may also be expressed with albumin or without albumin. There is no official definition of “ultra-high,” “high,” “intermediate” and “low” purity.

Recombinant DNA (rDNA) Technology - The process of isolating and splicing together different pieces of DNA (genes). When genes are transferred from one type of cell into another cell, the new cells can become “factories” for the production of the corresponding protein. In the case of recombinant factor VIII or IX, the gene coding for human factor has been transferred into animal cells. These cells are grown in large tanks in a “growth medium” that contains nutrients necessary for the survival and reproduction of the cells. The cells produce factor and secrete it into this growth medium. Factor is extracted from the growth medium and purified.

First Generation Recombinant Factor Products - Earliest factor concentrates produced through recombinant DNA technology. The growth medium used in the production process includes human and/or animal plasma proteins, and human albumin (purified from blood plasma) is added back into the final product to stabilize the factor.

Second Generation Recombinant Factor Products - Similar to first generation, however, no human albumin is added to the final product. Instead of human albumin, second generation factor VIII products are stabilized with sugar, such as sucrose.

Third Generation Recombinant Factor Products - Similar to second generation products, however, no animal/human albumin plasma proteins are added to the either the cell growth medium or the final product.

Recovery - The concentration of functional factor in the plasma after after administering a dose of factor (assuming a baseline factor level of 0%). The recovery is often expressed as a percentage of normal (e.g.; 100%) or as the number of international units per deciliter of blood (IU/dl). One unit of factor VIII per kilogram (kg) raises the plasma factor VIII level by approximately 2% (2IU/dl). The recovery of factor IX is lower: approximately 1% (1 IU/dl) for each unit of factor IX administered per kg of body weight. Recovery is used to help determine how much factor needs to be infused either prophylactically, following a bleed or to prepare for surgery.

Secondary prophylaxis - Regular schedule of factor replacement usually initiated after a specific pattern of bleeding has been established or to treat a target joint.

Spontaneous mutation - development of a hereditary disease for which there is no family history.

Target joint - term for a particular joint that has experienced repeated bleeds or at least four bleeds into one joint within a six month period.

Thrombophilia - categorical term for several distinct conditions where there is an increased tendency for excessive clotting.

von Willebrand Disease - bleeding disorder in which von Willebrand factor is either missing or does not function properly.

Acquired von Willebrand - A form of von Willebrand disease that is not inherited, but usually develops late in life.

Acronyms and Abbreviations

l: liter (approximately one quart)
    dl: deciliter (0.1 liter)
    ml: milliter (0.001 liter)
    FVIII: factor VIII (eight)
    FIX: factor IX (nine)
    IU: International Units
    vWD: von Willebrand Disease
    vWF: von Willebrand Factor

Symbols

±: Plus or minus
    ~: Equivalent to
    >: Greater than
    <: Less than

DISCLAIMER
The information contained on this site is provided for your general information only. The Cascade Foundation does not give medical advice or engage in the practice of medicine. In addition, the CFSA under no circumstances recommends particular treatment for specific individuals and in all cases recommends that you consult your physician or local treatment center before pursuing any course of treatment.

This information is provided free of charge for home care companies, manufacturers and the Hemophilia Treatment Center and members of the Arizona bleeding disorder community. It is intended to be used as a reference guide to educate and inform. Additional information will be added as needed.

The Board of Directors of the Cascade Foundation hope that this information will provide assistance in your research for the best possible care.

Clottiing Disorders
Hemophilia Glossary of Terms

HEMOPHILIA GLOSSARY OF TERMS

AIDS - Acquired Immune Deficiency Syndrome; disease that attacks and destroys the body's immune system, leaving the patient abnormally vulnerable to infections and many other diseases.

Albumin - The most abundant protein found in blood. Purified albumin is added to plasma-derived and first generation recombinant clotting factors to increase stablility.

Anemia - Condition in which the blood is either deficient in red cells, in hemoglobin, or in total volume.
Bleeding Disorders - A group of distinct conditions in which a person's body cannot properly develop a clot, causing an increased tendency for bleeding.

Carrier - An individual who possesses the gene for a condition, but does not necessarily have the condition.

Asymptomatic carrier - carrier who shows no outward signs of a condition.

Symptomatic carrier - carrier who has low factor levels and manifests bleeding symptoms.

This page contains general information about Hemophilia and other related bleeding disorders.

Hemophilia A

(Factor VIII Deficiency)

Hemophilia A is the most common type of hemophilia. It is also known as factor VIII deficiency or classic hemophilia. It is largely an inherited disorder in which one of the proteins needed to form blood clots is missing or reduced. In about 30% of cases, there is no family history of the disorder and the condition is the result of a spontaneous gene mutation.

Approximately one in 5,000 males born in the United States has hemophilia. All races and economic groups are affected equally.

When a person with hemophilia is injured, he does not bleed harder or faster than a person without hemophilia, he bleeds longer. Small cuts or surface bruises are usually not a problem, but more traumatic injuries may result in serious problems and potential disability (called "bleeding episodes").

There are different levels of hemophilia: mild, moderate, and severe:

People with mild hemophilia (6% to 49% factor level) usually have problems with bleeding only after serious injury, trauma, or surgery. In many cases, mild hemophilia is not discovered until an injury or surgery or tooth extraction results in unusual bleeding. The first episode may not occur until adulthood.
People with moderate hemophilia, about 15% of the hemophilia population, tend to have bleeding episodes after injuries. They may also experience occasional bleeding episodes without obvious cause. These are called "spontaneous bleeding episodes."
People with severe hemophilia, about 60% of the hemophilia population, have bleeding following an injury and may have frequent spontaneous bleeding episodes, often into the joints and muscles.

Everyone inherits two sex chromosomes, X and Y, from his or her parents. A female inherits one X chromosome from her mother and one X chromosome from her father (XX). A male inherits one X chromosome from his mother and one Y chromosome from his father (XY). The gene that causes hemophilia is located on the X chromosome.

A woman who gives birth to a child with hemophilia often has other male relatives who also have hemophilia. Sometimes, a baby will be born with hemophilia when there is no known family history. This means either that the gene has been "hidden" (that is, passed down through several generations of female carriers without affecting any male members of the family) or the change in the X chromosome is new (a "spontaneous mutation").

There are four possible outcomes for the baby of a woman who is a carrier. These four possibilities are repeated for each and every pregnancy:

A girl who is not a carrier
A girl who is a carrier
A boy without hemophilia
A boy with hemophilia

With each pregnancy, a woman who is a carrier has a 25% chance of having a son with hemophilia. Since the father's X chromosome determines the baby will be a girl, all the daughters of a man with hemophilia will be carriers. None of his sons, which is determined by the father through his Y chromosome, will have hemophilia.

Genetic counseling is available at most HTCs. These professionals have information to help you make family planning decisions.

In general, small cuts and scrapes are treated with regular first-aid: clean the cut, then apply pressure and a band-aid. Individuals with mild hemophilia can use a non-blood product called desmopressin acetate (DDAVP) to treat small bleeds. Deep cuts or internal bleeding, such as bleeding into the joints or muscles, require more complex treatment. The clotting factor missing (VIII or IX) must be replaced so the child can form a clot to stop the bleeding.

Some factor products are made from human blood products such as donated plasma. Others, called "recombinant factor," are made in a laboratory and do not use human blood products. The Medical and Scientific Advisory Council of the National Hemophilia Foundation encourages the use of recombinant clotting factor products because they are safer. Your doctor or your HTC will help you decide which is right for you. All factor treatments are injected or infused directly into the veins.

In cases of severe hemophilia, doctors sometimes recommend giving a regimen of regular factor replacement treatments (a therapy called prophylaxis) to prevent bleeding episodes before they happen. The Medical and Scientific Advisory Council of the National Hemophilia Foundation recommends prophylaxis as optimal therapy for children with severe hemophilia A and B.

Notify your doctor or HTC if your child does not respond to the usual dose of factor. In rare instances, people can develop an inhibitor, to standard factor treatment. In the event this occurs, your doctor or HTC will work with you to develop a special plan of care.

Hemophilia B

(Factor IX)

Hemophilia B is the second most common type of hemophilia. It can also be known as factor IX deficiency, or Christmas disease. It was originally named "Christmas disease" for the first person diagnosed with the disorder back in 1952.

It is largely an inherited disorder in which one of the proteins needed to form blood clots is missing or reduced. In about 30% of cases, there is no family history of the disorder and the condition is the result of a spontaneous gene mutation.

Hemophilia B is far less common than Hemophilia A. Occurring in about one in 25,000 male births, hemophilia B affects about 3,300 individuals in the United States. All races and economic groups are affected equally.

There are different levels of hemophilia: mild, moderate, and severe:

People with mild hemophilia (6% to 49% factor level) usually have problems with bleeding only after serious injury, trauma, or surgery. In many cases, mild hemophilia is not discovered until an injury or surgery or tooth extraction results in unusual bleeding. The first episode may not occur until adulthood.
People with moderate hemophilia, about 15% of the hemophilia population, tend to have bleeding episodes after injuries. They may also experience occasional bleeding episodes without obvious cause. These are called "spontaneous bleeding episodes.
People with severe hemophilia, about 60% of the hemophilia population, have bleeding following an injury and may have frequent spontaneous bleeding episodes, often into the joints and muscles.

There are four possible outcomes for the baby of a woman who is a carrier. These four possibilities are repeated for each and every pregnancy:

A girl who is not a carrier
A girl who is a carrier
A boy without hemophilia
A boy with hemophilia

Genetic counseling is available at most HTCs. These professionals have information to help you make family planning decisions.

Today, factor IX concentrates are the mainstay of treatment for those with hemophilia B, just as factor VIII concentrates are for hemophilia A. In cases of severe hemophilia, doctors sometimes recommend giving a regimen of regular factor replacement treatments (a therapy called prophylaxis) to prevent bleeding episodes before they happen. The Medical and Scientific Advisory Council of the National Hemophilia Foundation recommends prophylaxis as optimal therapy for children with severe hemophilia A and B.

Notify your doctor or HTC if your child does not respond to the usual dose of factor. In rare instances, people with hemophilia B can develop an inhibitor to standard factor treatment. Only about 3-5% of patients with severe hemophilia develop an inhibitor, a much lower incidence than in severe hemophilia A. However, anaphylactic reactions have occurred in some patients with hemophilia B inhibitors.

von Willebrand disease

Von Willebrand Disease is a bleeding disorder caused by a defect or deficiency of a blood clotting protein, called von Willebrand Factor. The disease is estimated to occur in 1% to 2% of the population. The disease was first described by Erik von Willebrand, a Finnish physician who reported a new type of bleeding disorder among island people in Sweden and Finland.

Von Willebrand Factor is a protein critical to the initial stages of blood clotting. This glue-like protein, produced by the cells that line the blood vessel walls, interacts with blood cells called platelets to form a plug which prevents the blood from flowing at the site of injury. People with von Willebrand Disease are unable to make this plug because they do not have enough von Willebrand Factor or their factor is abnormal.

Researchers have identified many variations of the disease, but most fall into the following classifications:

Type I: This is the most common and mildest form of von Willebrand disease. Levels of von Willebrand factor are lower than normal, and levels of factor VIII may also be reduced.

Type II: In these people, the von Willebrand factor itself has an abnormality. Depending on the abnormality, they may be classified as having Type IIa or Type IIb. In Type IIa, the level of von Willebrand factor is reduced, as is the ability of platelets to clump together. In Type IIb, although the factor itself is defective, the ability of platelets to clump together is actually increased.

Type III: This is severe von Willebrand disease. These people may have a total absence of von Willebrand factor, and factor VIII levels are often less than 10%.

Pseudo (or platelet-type) von Willebrand disease: This disorder resembles Type IIb von Willebrand disease, but the defects appear to be in the platelets, rather than the von Willebrand factor.

Von Willebrand Disease is a genetic disease that can be inherited from either parent. It affects males and females equally. A man or woman with VWD has a 50% chance of passing the gene on to his or her child. There are no racial or ethnic associations with the disorder. A family history of a bleeding disorder is the primary risk factor.

VWD subtype I and II are usually inherited in what is known as a "dominant" pattern. This means that if even one parent has the gene and passes it to a child, the child will have the disorder.

VWD Type III von Willebrand disease, however, is usually inherited in a "recessive" pattern. This type occurs when the child inherits the gene from both parents. Even if both parents have mild or asymptomatic disease, their children are likely to be severely affected.

Diagnosis of von Willebrand Disease can be difficult. Blood tests can be performed to determine the amount, structure and function of von Willebrand Factor. Since levels can vary, sometimes tests may need to be repeated. A person suspected of having von Willebrand Disease should be referred to a hematologist who specializes in the diagnosis and treatment of bleeding disorders.

Usually, people with VWD bruise easily, have recurrent nosebleeds, or bleed after tooth extraction, tonsillectomy or other surgery. Recurrent nosebleeds are also a hallmark of VWD. Women can have increased menstrual bleeding.

For minor bleeds, treatment may be unnecessary. There are a range of treatment choices that depend on whether the VWD is mild or severe.

Stimate® or desmopressin acetate (DDAVP), a nasal spray, is the treatment of choice for mild von Willebrand disease. Bleeding is usually controlled in individuals with mild von Willebrand disease by using this nasal spray to boost their own factor VIII and von Willebrand levels. DDAVP may be given to increase the amount of the von Willebrand factor long enough for surgery or dental procedures to be performed. DDAVP is a synthetic product that carries no risk of infectious disease.

For excessive bleeding, infusions of a factor VIII concentrate rich in von Willebrand factor, such as Humate-P®, Alphanate® or Koate DVI®, may be required. Humate-P and Alphanate® are the only FDA-approved Factor VIII concentrate for use in von Willebrand Disease.

If trauma occurs or surgery is anticipated, desmopressin acetate can be given as a means of raising the von Willebrand factor level.

Aspirin and many of the drugs used for pain can aggravate bleeding because they interfere with platelet function. People who have von Willebrand disease can take acetaminophen for pain relief because it does not inhibit platelet function.

The National Hemophilia Foundation's Medical and Scientific Advisory Council (MASAC) issued a treatment recommendation for von Willebrand disease in 1999. To receive a copy of this recommendation, call 1-800-42HANDI.

Other Factor Deficiencies

There are ten clotting factors that are necessary in forming a blood clot. Deficiencies in factors VIII and IX are well known to most people, but what of the other factor deficiencies? Not everyone is as familiar with these conditions because they are diagnosed so rarely. To date, deficiencies in eight of the lesser known coagulation factors have been documented in the medical literature. Many of these disorders were only discovered or described within the last 40 years.

Obtaining a detailed family history is an important component to diagnosing the condition. Most people with rare factor deficiencies are best seen by hematologists at hemophilia treatment centers. Making a proper diagnosis for some of these rare conditions requires a quality lab and an experienced hematologist.

Factor I Deficiency

aka. Fibrinogen deficiency, Afibrinogenemia, Dysfibrinogenemia, or Hypofibrinogenemia
Factor I deficiency is actually a collective term for several rare inherited fibrinogen deficiencies. Fibrinogen may be absent from the blood altogether (afibrinogenemia), present in only very low levels in the blood (hypofibrinogenemia), or measurable in normal quantities but defective (dysfibrinogenemia).
Fibrinogen helps platelets to glue together to form the initial "plug" in response to an injury. Therefore, people with factor I deficiency, have a combined bleeding disorder because both platelets and clotting are abnormal. The severity of the disorder is directly related to the amount of fibrinogen present.

Factor II Deficiency

aka. prothrombin deficiency
Factor II deficiency is inherited in an autosomal recessive fashion, which means it affects men and women equally Prothrombin is a precursor to thrombin, which converts fibrinogen into fibrin which in turn strengthens a protective clot. Factor II deficiency usually takes the form of an abnormality in the structure of prothrombin rather than a lack of the protein itself. People with a more severe factor II deficiency have severe bruising, bleeding from the nose and mouth, menorrhagia, as well as muscle bleeds, head bleeds and bleeding after trauma.

Factor V Deficiency

aka. Owren's disease, Labile factor deficiency, Proaccelerin deficiency or Parahemophilia (not to be confused with Factor V Leiden, which is a type of thrombophilia)
The role of the factor V protein is to be a catalyst or "accelerator" in the process by which prothrombin is converted to thrombin. Common characteristics of factor V deficiency are bruising, nose and mouth bleeds. Severe deep tissue bleeds are uncommon. Among people with severe forms of factor V deficiency, there can be joint bleeding and risks of head bleeds in newborns. Women can also present with menorrhagia.

Factor VII Deficiency

aka. Alexander's disease, Stable factor deficiency, or Proconvertin deficiency (not to be confused with acquired factor VII deficiency, which is associated with liver disease)
Factor VII was originally named serum prothrombin version accerlerator (SPCA) deficiency. The factor VII protein is part of the cascade of clotting factors that form the chain leading to a protective blood clot. Factor VII deficiency is usually severe. In fact patients with less than 1% Factor VII activity experience similar symptoms to hemophilia. People with severe factor VII are prone to joint bleeds. In addition to spontaneous nosebleeds, people can experience bleeds in the stomach, intestines and urinary tract. Head bleeds and muscle bleeds have also been reported. Women can have severe menorrhagia.

Factor X Deficiency

aka. Stuart-Prower Factor Deficiency
The factor X protein activates the enzymes that help to form a clot. Several genetic variations of Factor X with varying degrees of severity have been described in the medical literature. People with mild forms of the deficiency, usually do not experience bleeding episodes, but do have bleeding after trauma or surgery. Patients with severe forms of the disease, commonly have joint bleeding, gastrointestinal bleeds, and hematomas. Spontaneous head bleeds, spinal cord bleeds and bleeding at the site of the umbilical cord have also been reported. Women with Factor X deficiency may have menorrhagia or be susceptible to first trimester miscarriage.

Factor XI Deficiency

aka. Hemophilia C, Plasma Thromboplastin Antecedent (PTA) Deficiency, Rosenthal Syndrome
Factor XI is another part of the cascade of clotting factors that form the chain leading to a protective clot. Some people with Factor XI deficiency may have milder symptoms that those of hemophilia, but there can be quite a bit of variability with this deficiency. Individuals are not likely to bleed spontaneously, and hemorrhage normally occurs after trauma or surgery. Certain procedures carry an increased risk of bleeding such as, dental extractions, tonsillectomies, surgery in the urinary and genital tracts and nasal surgery. Joint bleeds are uncommon. Patients are more prone to bruising, nosebleeds, or blood in the urine. Woman may experience menorrhagia and prolonged bleeding after childbirth.

Factor XII Deficiency

aka. Hageman factor deficiency
The mystery of Factor XII centers on how the protein is a step in the process of forming a clot, but people with the deficiency usually do not experience bleeds and normally do not require treatment.

Factor XIII Deficiency

aka. Fibrin Stabilizing Factor deficiency
Factor XIII is the protein responsible for stabilizing the formation of a blood clot. In the absence of Factor XIII, a clot will still develop but it will remain unstable. When someone has a deficiency of Factor XIII, the tenuously formed clot will eventually break down and cause recurrent bleeds. The prolonged bleeding that is associated with Factor XIII is usually associated with trauma.

Clotting Disorders

Clotting disorders is a term used to describe a group of conditions in which there is an increased tendency, often repeated and over an extended period of time, for excessive clotting.

These disorders include inherited conditions such as Factor V Leiden, protein C deficiency, protein S deficiency, anti-thrombin deficiency and prothrombin 20210A mutations.

Thrombophilia affects a large number of people around the world. Factor V Leiden is the most common inherited abnormality in this class. It affects approximately 5% to 7% of the Caucasian population of European descent in the United States.

People who experience episodes of thrombosis, either as an isolated event or as a repeated event, may be affected with a thrombophilic disorder. There are people who have inherited the gene, who have an increased tendency for thrombosis, but may never personally experience a blood clot. Many people can have a known thrombophilic condition and never experience a thrombosis.

The development of a blood clot is called thrombosis. The vascular system includes both the venous system (the veins that deliver blood from the tissues to the heart) and the arterial system (the system that delivers blood from the heart to the tissues). Thrombotic episodes may occur in either system. The symptoms relate to the part of the vascular system in which they occur, the extent of the clot and whether the clot breaks off and travels to another part of the body (e.g., the lungs-pulmonary embolus, the brain-embolic stroke, etc). There are different terms used to further define these thrombotic episodes, such as deep vein thrombosis (DVT) or peripheral vascular disease, when the clots are in the arterial system (usually in the extremities). Although we are now able to determined the underlying cause in some patients and families for this tendency to an increased risk of excessive blood clotting, we are still not able to make this determination in all cases. This means that there is still more to be understood about why some persons and families have thrombophilia.

Recent research shows that these disorders contribute significantly to morbidity and mortality in the United States. Each year, more than 600,000 Americans die from abnormal blood clots.

Thrombophilia

Thrombophilia is the reverse side of the process of blood clotting when compared to hemophilia. While people with hemophilia have an increased tendency to bleed, people with thrombophilia have an increased tendency to clot. Just as hemophilia is caused by an abnormality of a blood-clotting factor, some forms of thrombophilia are also caused by an abnormality or deficiency of a blood-clotting factor. In some cases these clotting factors may have an abnormality that leads to an increase in their function (such as factor V Leiden).

Thrombophilia is not a new disease, but it has become a more recognized and more discussed due to an increased ability to test for and identify some of the underlying contributing abnormalities

Thrombosis is a very common medical problem. It is estimated that approximately two million people experience a DVT each year in the United States. In addition, nearly half of patients with deep vein clots experience long-term health consequences that adversely affect their quality of life and require millions of dollars of treatment. Thrombosis may manifest itself as the formation or presence of a blood clot in a blood vessel or one of the cavities in the heart. In fact, emboli (clots or plugs brought by the blood from another blood vessel and forced into a smaller vessel so as to obstruct the circulation) from deep vein clots are a leading cause of death in hospitalized patients. Annually, 200,000 to 300,000 patients develop this form of clot for the first time during a hospitalization. Nearly 40% of these patients suffer from a complication known as pulmonary embolism (a clot that travels to the lung and obstructs a significant amount of blood flow to the organ). This complication is fatal in 30% of the cases.

Both children and adults can have thrombophilia. However, it is more commonly diagnosed in adolescents and adults due to normal changes in the hemostatic balance that occur with growth and aging.

Genetic thrombophilia is an inherited abnormality that leads to an increased risk of thrombosis throughout a person's life. The most common inherited thrombophilic disorder is Factor V Leiden, initially described by Dr. Dahlback in 1993. Acquired thrombophilia refers to a group of disorders that an individual is not born with, but may develop throughout his or her life due to another circumstance such as illness. An example of acquired thrombophilia is the development of a lupus anticoagulant or antiphospholipid antibody syndrome.

People with thrombophilia may receive medications that affect the coagulation system, just as people with hemophilia do, but not always in the same manner. Some people with thrombophilia may be perscribed products to treat their thrombophilia either on a long-term or an intermittent basis, depending on the underlying cause of their thrombophilia. Some people with thrombophilia are treated with medications that are classified as blood thinners, which decrease a person's ability to form a clot. Examples of these medications include aspirin, heparin, low molecular weight heparin and coumadin. There are also some specific medications (thrombolytic agents) that are given under certain circumstances to dissolve clots. People with hemophilia , who have central venous access devices that have become clotted, may receive small doses of these medications locally. People with thrombosis may receive these agents in larger doses that are either given at the site of thrombosis or systemically. People with thrombophilia may receive medications only during a time of increased risk of thrombosis or for a prolonged period of time (even for a lifetime), depending on their specific diagnosis and clinical circumstances.

von Willebrands Disease
Other Factor Deficiencies

Hemophilia Basics

Hemophilia A
Hemophilia B