An overview of key hemophilia facts

The rare, inherited blood disorder hemophilia is estimated to impact approximately 20,000 individuals in the United States, and over 400,000 worldwide. Currently, there is no cure for hemophilia — but through ongoing research, medical experts are continually learning more about the disease.

Though there is still a lot of information to discover regarding hemophilia, the key facts we’re sharing below are a great place to develop an understanding of what is currently known.

Key hemophilia facts to know

What is hemophilia?

Hemophilia is a bleeding disorder that causes the blood not to clot properly. It is usually inherited but can sometimes be developed later in life. It can lead to spontaneous bleeding, as well as excessive bleeding following an injury or surgery. However, the main concern involves internal bleeding that can damage organs or tissues. 

What causes hemophilia?

Hemophilia occurs when a person lacks the clotting proteins normally found in the blood. More specifically, hemophilia A is caused by a lack of clotting factor VII, while hemophilia B is caused by a lack of clotting factor IX. The lower the amount of clotting factors, the more severe a person’s hemophilia will be. 

How is hemophilia inherited?

In almost all cases, hemophilia is a genetic, sex-linked disorder carried in the X chromosome. Girls inherit one X chromosome from their father and one X chromosome from their mother, so if they inherit a hemophilia gene, it will likely be recessive. Because boys inherit an X chromosome from their mother and a Y chromosome from their father, they are more likely to be born with hemophilia. 

How is hemophilia diagnosed?

While severe cases of hemophilia are typically diagnosed early in life, milder forms are generally discovered later into adulthood, with some people only discovering they have hemophilia after receiving surgery. If a doctor suspects a person may have hemophilia, a test can be ordered to assess the levels of clotting proteins in a person’s blood and determine the severity of the disease.

A better understanding of hemophilia is only possible when patients participate in research — which is why clinical trials are so important. If you’d like to learn more about studies that are enrolling now, click the button below.