Genetics of Hemophilia

Genetic conditions can be inherited, or passed down, from your parents. They can also happen randomly through a new or spontaneous mutation.

What role do genes play in hemophilia?

Hemophilia is a rare genetic bleeding disorder that causes a delay in clot formation. In hemophilia, there is a mutation in the gene that contains the instructions for creating one of several important blood-clotting proteins, called “factors.”

Types of hemophilia

There are 2 main types of hemophilia: A and B.

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  • Hemophilia A, or factor VIII deficiency, affects approximately 1 in 5,000 males.
  • Hemophilia B, or factor IX deficiency, affects approximately 1 in 20,000 males.

Genes and hemophilia

Hemophilia is most often inherited, but in one-third of cases, it is caused by a new or spontaneous mutation. Because of how hemophilia is inherited, it primarily affects men. However, in rare cases, women can be affected, and typically have mild hemophilia, experiencing the same symptoms and complications as men. 16% of mild hemophilia A cases affect women.

Hemophilia severity is classified based on the factor level in a person’s blood:

  • Mild (>5% to 40%)
  • Moderate (1% to 5%)
  • Severe (<1%)

Individuals with hemophilia may bleed spontaneously (without a known cause) from an injury, inside or outside of the body, and longer than those without hemophilia. Common sites of internal bleeding are joints and muscles; bleeding in these locations can lead to joint damage and arthritis. Unexplained bruising and external bleeding also may occur, including nose bleeds and prolonged bleeding from minor cuts and dental work.

How is gene therapy aimed at addressing hemophilia symptoms?

Frequently asked questions

Genes are the body’s instruction manual. The human body is made up of trillions of cells. At the center of each cell is the nucleus, which contains all of the instructions the body needs to function.

Learn about how these instructions are stored on chromosomes, made of DNA.

To understand the science behind gene therapy research, we first need to understand the role genes play in the body.

Watch the Video: Discover the Role Genes Play in Hemophilia.

No. Gene transfer research, specifically, aims to address hemophilia by providing new instructions to the cells rather than changing your existing DNA to fix the specific gene mutation.

See more Myths.

How long has gene therapy been studied in hemophilia?



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