Hemophilia

Hemophilia is a rare, inherited blood disorder that causes your blood to clot less, which results in an increased risk of bleeding or bruising.

Hemophilia happens because your body doesn’t make enough protein (clotting factors) to help your blood form clots. Clotting factors are proteins in your blood. They work with your platelets to form blood clots that control bleeding. Low clotting factor levels increase bleeding risk.

There are several types of hemophilia. Hemophilia may be severe, moderate or mild based on the amount of clotting factor in your blood.

Healthcare providers treat this condition by replacing the missing clotting factor. There isn’t a cure for hemophilia, but people who receive treatment generally live nearly as long as people who don’t have hemophilia. Providers are researching gene therapy and gene replacement therapy as new ways to treat and possibly cure hemophilia.

Can people develop hemophilia?

Yes, but that rarely happens. Acquired hemophilia, or hemophilia that isn’t inherited, develops when autoantibodies start to attack a specific clotting factor. (Antibodies are protective proteins your immune system makes. Autoantibodies attack antibodies, essentially attacking your body’s own cells, tissues and proteins.)

Is hemophilia a common disease?

No, it’s not. According to the U.S. Centers for Disease Control and Prevention (CDC) in August 2022, about 33,000 people in the U.S. have hemophilia. Hemophilia typically affects men and people assigned male at birth (AMAB). Rarely, women and people assigned female at birth (AFAB) may have clotting factor levels that are so low that they develop symptoms such as having very heavy periods.

What are hemophilia types?

There are three types of hemophilia:

• Hemophilia A: This is the most common type of hemophilia. It happens when you don’t have enough clotting factor 8 (factor VIII). The CDC estimates about 10 in 100,000 people have hemophilia A.
• Hemophilia B: Hemophilia B happens when you don’t have enough clotting factor 9 (factor IX.) The CDC estimates about 3 in 100,000 people in the U.S. have hemophilia B.
• Hemophilia C: Hemophilia C is also known as factor 11 (factor XI) deficiency. This hemophilia type is very rare, affecting 1 in 100,000 people.

Is hemophilia a serious illness?

It can be. People with severe hemophilia may develop life-threatening bleeding, but they’re more likely to develop bleeding in their muscles and joints.