What Causes Hemophilia?

In people with hemophilia, one or more important blood clotting factors—proteins that allow the blood to clot—is/are missing. There are several types of clotting factors and two main types of hemophilia.

Hemophilia A, or classic hemophilia, accounts for 80 percent of cases. This type results from genetic deficiency of Factor VIII (8), also known as antihemophilic factor. Hemophilia B, also called Christmas disease, results from a deficiency in Factor IX (9). Both factors are necessary for normal blood coagulation. Because the genes for the factors are carried on the X chromosomes, hemophilia only affects males; women may be carriers and pass the disorder to their offspring.

Hemophilia Prevention

There is no way to prevent hemophilia, although those with a family history of it may benefit from genetic counseling when considering having a child.


Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

U.S. Food and Drug Administration (FDA)

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 30 Aug 2011

Last Modified: 17 Apr 2014