Hemophilia is a rare bleeding disorder in which the blood does not clot normally. Hemophilia is a monogenic disease (a disease that is caused by a genetic defect in a single gene). There are two types of hemophilia caused by mutations in genes that encode protein factors which help the blood clot and stop bleeding when blood vessels are injured. Individuals with hemophilia experience bleeding episodes after injuries and spontaneous bleeding episodes that often lead to joint disease such as arthritis. The most frequent forms of hemophilia affect males.
Underlying Genetic Cause of Disease
The most prevalent form of the disease, hemophilia A, is caused by a defect in the Factor 8 gene, while defects in the Factor 9 gene lead to hemophilia B.