Hemophilia Causes
The major risk factors for hemophilia are:
- Having relatives with hemophilia
- Being male
Most of the time, hemophilia is inherited, caused by a mutation in the genes that make proteins that help form blood clots. Hemophilia A is caused by a mutation that reduces or stops the function of clotting factor VIII (FVIII), and hemophilia B is caused by a mutation that reduces or stops the function of clotting factor IX (FIX).
Males are far more likely than females to have hemophilia because the mutation is passed through the X chromosome. While females inherit an X chromosome from each parent, males inherit an X chromosome from the mother and a Y chromosome from the father.
It takes a single copy of the mutated gene to cause hemophilia in males, but two copies of the mutated gene are needed for the disorder to occur in females. A female with a single copy of the mutated gene is a hemophilia carrier and can pass on the affected X chromosome to her children.
In very rare cases, hemophilia can be acquired, which happens when the patient’s immune system attacks the clotting factors. Acquired hemophilia may be associated with:
Occasionally, the cause is unknown.
Symptoms of Hemophilia
People with hemophilia may bleed continuously or notice bruising after an injury, surgery, dental care, or a shot, such as a vaccination.
Additional symptoms include:
- Spontaneous bleeding (in patients with severe hemophilia)
- Pain, swelling, or tightness in the joints
- Bloody urine or stool
- Frequent nosebleeds
- Unexplained irritability in infants
Patients should seek emergency care if the bleeding does not stop.
Hemophilia may also cause internal bleeding, most commonly in the muscles and joints. If joints feel swollen and hot to the touch and it’s painful to bend them, patients should seek emergency care.
Hemophilia also increases risk of bleeding in the brain, which can occur after even a minor head bump. It’s important to seek emergency care if a patient has signs of bleeding in the brain, which include:
- Lasting headache
- Continuous vomiting
- Sleepiness or lack of energy
- Double vision
- Sudden weakness or loss of coordination
- Convulsions or seizures
- Behavior changes
Diagnosing Hemophilia
People with severe hemophilia are typically diagnosed early in life. People with less severe forms of the disorder might not find out they have it until they bleed continuously after a significant injury or surgery.
At UT Southwestern, our doctors might recommend a blood test to measure how much clotting factor is in the blood and how long it takes the blood to clot. We use this information to diagnose the type of hemophilia and to classify the disorder as mild, moderate, or severe.
We also offer genetic testing for hemophilia, which is recommended for people who are considering becoming pregnant and have a family history of the disorder (testing is not always covered by insurance).
Hemophilia Treatment
Our multidisciplinary team will determine the appropriate course of treatment, which depends on the severity of the disorder, and provide education on how to prevent complications and stay healthy.
Replacement therapy, which involves injecting clotting factors into the patient’s vein, is the primary treatment for hemophilia. Clotting factors may be made from donated human plasma or produced using DNA technology (known as recombinant clotting factors).
Replacement therapy can be used to stop bleeding events and as a preventive measure. Working with their health care team, patients can learn to do replacement therapy at home.
We also can prescribe medications, including:
- Desmopressin, a synthetic hormone that helps increase clotting factor levels when injected in a vein or sprayed in the nose of someone with mild hemophilia
- Anti-fibrinolytics, medications for mild hemophilia that slow the rate at which clots break down
- Emicizumab (Hemlibra), which does not contain clotting factors and helps people with hemophilia A avoid or reduce bleeding events
- Fibrin sealants, which can help heal wounds
Physical therapy can help with recovery after internal bleeding in the joints.
Some people undergoing replacement therapy develop inhibitors, which are antibodies that make treatment less effective. We test patients regularly for inhibitors and provide specialized care for patients who develop inhibitors.
In addition to treatment, people with hemophilia can help prevent complications by maintaining healthy habits, including:
- Exercising (while avoiding contact sports)
- Taking good care of their teeth
- Avoiding medications that can interfere with clotting and make bleeding worse
- Keeping up with vaccinations
- Modifying their homes and furniture as needed to avoid falls and injuries on sharp corners