Hemophilia is a rare, inherited bleeding disorder in which the blood does not clot normally.
People who have hemophilia may bleed for a longer period of time following an injury or accident. People with hemophilia may also bleed internally, especially in the joints (such as the knees, ankles, and elbows).
Approximately 18,000 people in the United States have hemophilia, and about 400 babies are born each year with this disorder in the U.S. Although hemophilia usually occurs only in males, there are very rare exceptions in which a female will have the blood disorder.
People with hemophilia have problems with certain proteins in their blood, called clotting factors. Clotting factors help blood to clot. Hemophilia can occur if there is a low level of one of the clotting factors or if a clotting factor is completely missing.
When clotting factors are missing, or your body does not have enough clotting factors, it can take a long time for your blood to clot after an injury or accident.
Hemophilia: Understanding Clotting and Clotting Factors
An injury (such as a cut) to a blood vessel causes a complex chain of events that will result in a blood clot. This is called the clotting process, which is also known as blood coagulation. Clotting is your body's reaction to bleeding to keep you from losing too much blood. Losing too much blood can be life threatening and can damage your internal organs.
Clotting factors are proteins in the blood that work with platelets -- small blood cell fragments -- to help the blood to clot. When blood vessels are damaged, clotting factors help the platelets stick together to plug cuts and breaks at the site of the injury.
In people with hemophilia, blood does not clot as it should due to missing or low levels of clotting factors. If this occurs, there may be heavy blood loss or injured body tissues and organs, which may result in permanent damage or even death.
Hemophilia is caused by a defect in one of the genes that determines how the body makes certain blood-clotting factors. The genes are located on the X chromosomes, which determine if a baby is a boy or girl.
(Click Causes of Hemophilia to learn more about what causes hemophilia and how hemophilia is inherited.)
There are two main types of hemophilia:
hemophilia A and
hemophilia B. In hemophilia A, clotting factor 8 (VIII) is low or missing. Approximately 9 out of 10 people with hemophilia have type A. In hemophilia B, clotting factor 9 (IX) is low or missing.
Common Symptoms of Hemophilia
The major signs and symptoms of hemophilia are bleeding and bruising.
Bleeding often occurs internally, in joints and muscles. If bleeding in the brain occurs, it is considered a medical emergency.
Hemophilia symptoms can be:
The severity of hemophilia symptoms is determined by the amount of clotting factor in the blood. Most people (about 7 out of 10) with
hemophilia A have the severe form of hemophilia symptoms. People who do not have hemophilia have a clotting factor 8 activity of 100 percent. People with severe hemophilia A have a clotting factor 8 activity of less than 1 percent.
A doctor making a hemophilia diagnosis will usually need to:
- Review the patient's personal and family medical history
- Perform a physical examination
- Order blood tests.
The tests will indicate:
- Whether there is a bleeding problem
- If the bleeding problem is due to hemophilia or another cause
- The severity of the disorder.
Hemophilia treatment most commonly involves replacement therapy. Replacement therapy entails injections of the low or missing clotting factors directly into the bloodstream.
Replacement therapy can be used on a long-term basis to prevent bleeding. People with severe hemophilia are more likely to receive this type of preventive replacement therapy. Replacement therapy can also be given on demand (as needed) to stop bleeding when it occurs. This therapy is more common in those with milder hemophilia.
Early treatment for bleeding is important to prevent or limit damage to joints, muscles, or other parts of the body.
Replacement therapy is often done at home. Home hemophilia treatment has many benefits. However, it is important to be trained to do home infusions properly and safely.
Exercise is important for children and adults living with hemophilia. Talk with your doctor about the type of exercise that is best for you or for your child and what to do to prevent injuries.
If you or your child has hemophilia, learn as much as you can about the disorder and if possible, join a support group.
Hemophilia treatment centers (HTCs) are located in many areas of the United States. These centers can provide treatment, education, and support to hemophilia patients, their families, and their healthcare providers.
Hemophilia Statistics
Hemophilia A is the most common type of hemophilia, affecting 1 in 5,000 to 10,000 males worldwide.
Hemophilia B is less common; it affects 1 in 20,000 to 34,500 males worldwide.
Other Names for Hemophilia
Other names for hemophilia include:
Hemophilia A
- Classic hemophilia
- Factor 8 (VIII) deficiency.
Hemophilia B
- Christmas disease
- Factor 9 (IX) deficiency.
Key information about hemophilia includes the following:
- Hemophilia is a rare, inherited bleeding disorder.
- In the United States, approximately 400 babies are born with hemophilia each year.
- Hemophilia almost always occurs in males.
- People born with hemophilia have problems with certain proteins in the blood, which are called clotting factors. Clotting factors help blood clot.
- Hemophilia can occur if there is a low level of clotting factors or if there is a clotting factor that is completely missing.
- When clotting factors are missing, or your body does not have enough clotting factors, it can take a long time for your blood to clot after an injury or accident. Bleeding often occurs internally.
- There are two main types of hemophilia: A and B. People with hemophilia A have low levels of clotting factor 8 or are missing it altogether. People with hemophilia B have low levels of clotting factor 9 or are missing it altogether.
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