Skip Navigation Bar


Hemophilia is an inherited disease, most commonly affecting males, that is characterized by a deficiency in blood clotting. The responsible gene is located on the X chromosome, and since males inherit only one copy of the X chromosome, if that chromosome carries the mutated gene then they will have the disease. Females have a second, usually normal, copy of the gene on their other X chromosome, so they are capable of passing on the disease without experiencing its symptoms.

Images and animations are courtesy of the National Human Genome Research Institute's Talking Glossary (

Materials for Hemophilia



Description: An overview on hemophilia


Description: Questions answered by GARD Information Specialists, links to resources, information about research, conferences, genetic testing, and genetic services

History of Bleeding Disorders

Description: Information on the history of bleeding disorders

Learning About Hemophilia

Description: An overview on hemophilia

Teen Health: Hemophilia

Description: Hemophilia information written for teens and links to information on related topics

What Are Hemophilia A & B?

Description: Hemophilia A and B are two disorders characterized by slow and inefficient formation of blood clots leading to prolonged bleeding and spontaneous internal bleeding.

What is Hemophilia?

Description: An overview on hemophilia

Interactive Tutorials

Your Genes Your Health - Hemophilia

Description: An interactive Web site exploring Hemophilia disease.


Playing it Safe With Hemophilia

Description: A video about hemophilia and playing sports