What is hemophilia?
Hemophilia is a medical condition that limits the blood’s ability to clot. Normally, bleeding stops when blood clots form, due to the combined action of proteins called clotting factors and platelets, a type of blood cell. In people with hemophilia, the body doesn’t produce enough of a particular clotting factor or it makes ineffective clotting factors.
The severity of hemophilia symptoms depends on how much clotting factor your body produces. Some people with hemophilia have clotting factor levels that causes only mild symptoms, but those with lower levels experience more serious symptoms.
Thanks to advances in hemophilia therapies, people with the condition can live full lives—even with severe disease. Penn Medicine is a Centers for Disease Control and Prevention (CDC)-designated center for hemophilia care. Our hematology experts, including bleeding disorders specialists, use the most advanced therapies to treat hemophilia. Medications, innovative treatments like gene therapy, and specialized physical therapy all help to manage the condition. Our researchers are also working to develop new therapies and a potential cure for hemophilia.
Hemophilia symptoms
People with hemophilia have increased bleeding. The frequency and circumstances of bleeding depend on how severe hemophilia is:
- Mild hemophilia: People with mild hemophilia may only experience prolonged bleeding with medical or dental procedures or serious injuries. Heavier bleeding may also be experienced during menstruation or delivery. Doctors help people plan for these events when possible and take preventive steps. Learn more about our evaluations of heavy periods.
- Severe hemophilia: People with severe hemophilia bleed more easily from injuries. They may also bleed for no apparent reason, a situation called spontaneous bleeding. Bleeding inside the body can damage muscles and joints, especially the ankles, knees, and elbows. The joints may develop a severe form of arthritis called hemophilic arthropathy. Internal bleeding can also harm organs, including the brain. Fortunately, people can now take effective, ongoing treatment to prevent these complications.
What causes hemophilia?
In most cases, hemophilia is inherited, resulting from changes to certain genes that control clotting factor production. The genes responsible — and the clotting factors they’re associated with — determine the type of hemophilia.
In rare cases, hemophilia is acquired, meaning people are not born with it. In these cases, hemophilia results from damage to clotting factor by immune system proteins. This type of hemophilia can occur during or immediately after pregnancy or when you have an autoimmune disorder and grow older. Sometimes the cause of acquired hemophilia is not known.
Hemophilia A, also called classic hemophilia, is the most common form. It’s caused by changes to the F8 gene, which controls clotting factor VIII.
Because the F8 gene sits on the X chromosome, severe disease typically gets passed down only to male children, who have only one X chromosome. Even then, just because a parent has hemophilia doesn’t mean it will automatically get passed on.
Females have two X chromosomes. If one has the F8 change that causes hemophilia, the other can still make normal clotting factor VIII. For a female child to inherit severe disease, both parents must have hemophilia, a very rare circumstance. However, females with one copy of the hemophilia A variant may still have symptoms and clotting factor low enough to be diagnosed with mild forms of hemophilia.
Women who have one copy of the factor VIII variant are called carriers; they can still pass the genetic change on to their children.
Hemophilia B is sometimes called Christmas disease, after the last name of the first child diagnosed with this condition. It’s caused by changes to the F9 gene, responsible for clotting factor IX.
Hemophilia B follows the same inheritance patterns as hemophilia A.
Hemophilia C is rarer than hemophilia A or B. It’s caused by changes to the F11 gene, which controls clotting factor XI.
Hemophilia C varies in other ways, too. Because the gene sits on a different chromosome, the condition gets passed down to both male and female children. For most patients, symptoms are mild.
How is hemophilia diagnosed?
Some families already know they have a history of hemophilia, so children get diagnosed right away. Otherwise, severe hemophilia typically gets noticed in early childhood when it causes symptoms.
With mild hemophilia, age at diagnosis varies. An older girl may get diagnosed after menstruation begins, for example. Others are diagnosed after injuries that cause bleeding or when blood tests done for unrelated reasons show clotting factor changes. Sometimes mild hemophilia is not discovered until adulthood.
Tests for hemophilia look at the blood’s ability to clot and how long the process takes, as well as the amount of particular clotting factors. Genetic testing can look for the inherited change responsible.
Hemophilia treatment
Medications called factor replacements can treat inherited hemophilia by supplying the missing factor to promote blood clotting. Other medications called non-factor replacement therapies can help the blood clot without replacing the clotting factor. Mild or moderate cases may only need treatment in special situations, such as before surgery or during childbirth. More severe inherited hemophilia often requires ongoing treatment.
Researchers have also developed gene therapy to treat hemophilia. The therapy works by adding a working copy of the gene that gives your body instructions on how to make the missing clotting factor. The Food and Drug Administration has approved gene therapies for hemophilia A and hemophilia B, with additional clinical trials underway. Gene therapy can potentially remove the need for frequent treatment.
For acquired hemophilia, doctors typically prescribe therapy that suppresses the immune system.
Managing hemophilia with physical therapy
Hemophilia can cause bleeding in your muscles and joints, which, over time, can damage muscle fibers, cartilage, and bone. Physical therapy plays a crucial role in helping to prevent damage and support your recovery after a bleeding episode. A physical therapist can lead you through stretches and exercises that strengthen your muscles, improve flexibility, reduce pain and stiffness, and lower your risk of a fall. Therapists can also give you exercise plans to do at home and may recommend assistive devices that offer support for your joints.
At Penn Medicine, our physical therapists provide a thorough evaluation and create a treatment plan based on your needs. We’ll review your health history, assess your range of motion, and observe your walking pattern to identify mobility concerns. In addition to our ongoing support and care, our physical therapists can also help you recover from hemophilia complications, like a stroke, or monitor your progress if you’re part of a clinical trial for a bleeding disorder. We support your overall well-being and help improve your quality of life.
Leaders at the forefront of hemophilia care
As one of the largest hematology practices in the region, we have decades of experience diagnosing and treating hemophilia and other bleeding disorders. Penn Medicine’s specialists provide complete clinical evaluations, accurate diagnoses, and access to the latest, advanced therapies to reduce bleeding episodes. We also work with your other doctors to ensure you receive hemophilia treatment during procedures that can cause excessive bleeding.
Penn Medicine’s innovative research helps lead the advancement of bleeding disorder care. Our team offers emerging treatments and works closely with scientists who conduct clinical trials on cell and gene therapy for conditions like hemophilia. Your hemophilia care is also coordinated with other specialists across our health system, like orthopedic doctors and physical therapists, to provide you with the most complete and personalized care and guidance.
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