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Also called: classic hemophilia, factor VIII (8) deficiency, Christmas disease, factor IX (9) deficiency

What is hemophilia?

Hemophilia is a rare bleeding disorder in which the blood does not clot properly. A person with hemophilia may bleed longer after an injury or may bleed internally, which can damage tissues and organs and may be life-threatening. Hemophilia does not cause a person to bleed faster than someone without the disorder, just longer.

Hemophilia is caused by having little or no clotting factor. Clotting factor is a plasma protein in the blood that is needed for normal blood clotting. There are 12 clotting factors in the blood. Lacking even one of these clotting factors causes the prolonged bleeding seen with hemophilia.

Blood cells called platelets need clotting factors to help clot the blood. When a person is injured and blood vessels are damaged, clotting factors help platelets stick together to form a clot and stop the bleeding. This process of blood cells sticking together to stop the bleeding is called coagulation.

There are three types of hemophilia, but the main types are hemophilia A and hemophilia B. The type of hemophilia a person has depends on which clotting factor is low or missing:

  • Hemophilia A — is caused by a deficiency of clotting factor VIII (8).
  • Hemophilia B  is caused by a deficiency of clotting factor IX (9).
  • Hemophilia C  is caused by a deficiency of clotting factor XI (11).

Hemophilia can be mild, moderate or severe based on how much clotting factor is low or missing in the blood. A person with mild hemophilia may only have problems with bleeding after surgery or a traumatic injury. If the level of clotting factor is very low, a person may also have spontaneous bleeding episodes, often into the muscles and joints with little or no injury.

How common is hemophilia?

Hemophilia affects about 20,000 people in the United States and about 400,000 people worldwide.

Hemophilia A is the most common type of hemophilia. It accounts for about 80 percent of all hemophilia cases and is four times more common than hemophilia B.

Both hemophilia A and B affect all races and economic groups equally and are usually inherited, which means passed on from parent to child through genes. However, hemophilia can also happen by a new gene mutation (defect) that occurs before birth; this occurs in one-third of people with hemophilia.

How Do You Get Hemophilia A or B?

Chromosomes are the proteins that carry someone’s genetic information. Boys have a Y chromosome and an X chromosome. Girls have two X chromosomes. Because the gene that causes hemophilia A and B is located on the X chromosome, the disorder is usually passed from mother to son. Because the father gives the Y chromosome in a male birth, a hemophiliac male cannot pass the defective gene (since it is located on the X chromosome). However, since the father provides one of the X chromosomes (his X chromosome carries the defect), every girl born to a hemophiliac male will be a carrier.

A woman or girl who is a known carrier has a 50% chance with each male birth of having a baby boy with hemophilia (depending on which one of the two X chromosomes she contributes), She also has a 50% chance of having a daughter who carries the gene (depending on which one of the two X chromosomes she contributes).

Some females who carry the gene can have symptoms of increased bleeding such as heavy nosebleeds or heavy menses, but they usually do not show any signs or symptoms.

How Do You Get Hemophilia C?

Unlike hemophilia A or B, hemophilia C is passed on by either the mother or the father. Most people with factor XI deficiency will have few symptoms or none at all. How the amount of factor XI in a person's blood affects the severity of symptoms is not well known. People with only a mild deficiency in factor XI can have serious bleeding episodes. Usually, factor XI deficiency is a mild bleeding disorder, but this can vary widely, even among family members, which can make it hard to diagnose.

What are the signs and symptoms of hemophilia?

Signs and symptoms of hemophilia usually depend on how low the factor levels are, but may include the following:

  • Prolonged bleeding from minor cuts and scrapes
  • Bruising easily or bruises that are large, unexplained or in unusual places
  • Nosebleeds that are hard to stop
  • Blood in the urine or stool
  • Excessive bleeding after surgery or a dental procedure
  • Menstrual periods that are heavy or last more than seven days
  • Joint pain and swelling
  • Unusual bleeding after vaccinations

How is hemophilia treated?

Treatment for hemophilia is based on how severe the disorder is, the person’s activity level, and the medical or dental procedures needed. Current therapies include the following:

  • Clotting factor replacement therapy—is the main treatment for hemophilia, which replaces the clotting factor that is low or missing in the blood.
    • Replacement therapy for hemophilia is given in a vein (IV) and can be given at a medical facility or at home. After the clotting factor is given, it works quickly to increase the factor levels.
    • Clotting factors for replacement therapy can be concentrates derived from the plasma. Plasma is the part of the blood that has all the clotting proteins of donated human blood. Each sample is screened to prevent the spread of diseases. Examples of these include Hemofil M®, Koate-DVI® and Monoclate-P®.
    • Clotting factors for replacement therapy can also be man-made concentrates called recombinant clotting factors. Examples of recombinant factor products are Advate®, Helixate FS®, Kogenate FS® and Xyntha®.
    • Treatment with factor products may be given on an as-needed basis to stop bleeding when it occurs.
    • Factor therapy that is given on a regular basis (usually several times a week) to prevent bleeding and reduce joint damage is called prophylaxis therapy (sometimes called a prophy). Research has shown that children with hemophilia who were treated regularly to prevent bleeding had less joint damage by age 6 than did children who were only treated after a bleed started.
  • Desmopressin acetate (DDVAP)—is used to treat some people with mild hemophilia A.
    • DDVAP is a man-made hormone and is not used to treat hemophilia B or severe hemophilia A.
    • VonWillebrand factor is bound to factor VIII in the blood. Without von Willebrand factor attached, the factor VIII (8) is destroyed quickly. The von Willebrand factor is stored in the lining of the blood vessels and in platelets. DDAVP causes the release of von Willebrand factor from its stores. Because it is bound to factor VIII (8), it increases the amount of the clotting factor VIII (8) that exists in the blood.
    • Treatment with DDAVP is only given in certain situations, such as before a dental procedure to help reduce or prevent bleeding. If used often, this medicine will not work as well.
    • Some people do not have a good rise in their factor VIII levels with DDAVP. To see if a person will have a good response from its use, your doctor may order a Stimate® or DDAVP challenge. This will measure the amount of factor VIII (8) in the blood before and after being given the medicine.
    • DDAVP is given by IV or as a nasal spray (Stimate®).
  • Antifibrinolytic medicines—are used to help keep blood clots together once formed.
    • An antifibrinolytic medicine may sometimes be used along with clotting factor replacement therapy or DDAVP.
    • These drugs include tranexamic acid (Lysteda®) and epsilon aminocaproic acid (Amicar®).
    • Antifibrinolytic medicines are usually taken before and after a dental procedure. They are used to stop bleeding from the mouth or nose or to treat heavy menses.
  • Gene therapy—might be used to alter or correct the defective genes that cause hemophilia.
    • Researchers continue to test gene therapy in clinical trials to find ways to prevent or reduce bleeding in people with hemophilia.
    • Genetic research is underway to develop a method of inserting more useful clotting factors into the cells of people with hemophilia for better blood clotting.
    • Researchers are focusing on gene therapy that may help people with hemophilia to begin producing clotting factors normally. This might reduce or remove the need for regular replacement therapy.

What are the survival rates for hemophilia?

Although hemophilia is a lifelong disorder with no cure, most people with hemophilia have a normal life expectancy. With the right treatment and proper self-care, a person with hemophilia can look forward to living a healthy, active life.

Why choose St. Jude for your child’s hemophilia treatment?

  • The nurse-to-patient ratio at St. Jude is unmatched—averaging 1:3 in hematology and oncology, and 1:1 in the Intensive Care Unit.
  • A close-knit team of experienced staff at St. Jude provides the care needed to manage hemophilia symptoms and prevent long-term health problems.
  • St. Jude helps each patient and family deal with the physical, emotional, psychological, educational and other issues related to having hemophilia.
  • The St. Jude Bleeding Disorders Program is an important resource for families and children affected by the disorder. The program has been named a Hemophilia Treatment Center by the federal government.
  • St. Jude hemophilia patients have access to the latest clinical trials, including a study looking at the extent of joint disease in hemophilia patients and the safety of the nation’s blood supply.
  • One hemophilia clinical trial explores the use of gene therapy for hemophilia B. The treatment involves inserting the gene for the factor IX (9) protein into liver cells using a one-time vein infusion. The goal is to restore blood-clotting function and remove the need for frequent doses of factor IX (9) for bleeding.
  • The vector used in the gene therapy study is produced at the Children’s GMP, LLC, which is located on the St. Jude campus. St. Jude was the first pediatric research center to have an on-site Good Manufacturing Practices facility. The Children’s GMP produces biopharmaceutical products under government-approved manufacturing guidelines.

Associated Clinical Trials

GENETX: Assessment for Gene Therapy Decisions

Gene Therapy Communication: Use of a Needs Assessment to Drive Decision-Aids for Gene Therapy for Rare Diseases (GENETX)

Diseases Treated:

Neurological Disorders
Sickle Cell Disease
Inherited Genetic Diseases


  • Non-therapeutic clinical trial
  • Interviews conducted remotely
  • 18-35-year-olds with rare genetic diseases
  • Parents or caregivers of patients under 21 with rare genetic diseases
  • Health care workers for gene therapy patients
View Trial

Go-8: Gene Therapy for Hemophilia A

Gene Therapy for Hemophilia A Using a Novel Serotype 8 Capsid Pseudotyped Adeno-Associated Viral Vector Encoding Factor VIII-V3

Diseases Treated:

Hemophilia A


  • Male
  • At least 18 years old
  • Severe hemophilia A
View Trial

HEMOCOG: Neurocognitive Functions, Health Literacy, and Transition Readiness in Pediatric Hemophiliacs

Examining Cognition, Health Literacy, Transition Readiness, and Educational Experiences in Patients with Hemophilia

Diseases Treated:



  • St. Jude hemophilia patients
  • 6–18 years old
  • Speak English 
View Trial

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