Hemophilia A causes
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Hemophilia A Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Fahd Yunus, M.D. [2]
Overview
Mainly, Hemophilia is caused by an inherited X-linked recessive trait, with the defective gene located on the X chromosome.
Causes
Females have two copies of the X chromosome, so if the factor VIII gene on one chromosome is defective, the gene on the other chromosome can compensate by producing sufficient factor VIII. Males, however, have only one X chromosome. Thus, if the factor VIII gene on that chromosome is defective, they will have hemophilia A. Therefore, most people with hemophilia A are male. If a woman has a defective factor VIII gene, she is considered a carrier. This means the defective gene can be passed down to her children. Boys born to a woman who carries the defective gene have a 50% chance of having hemophilia A, while their daughters have a 50% chance of being a carrier. All female children of men with hemophilia A carry the defective gene.
There are case reports that in rare cases, Hemophilia can be caused by acquired causes which lead to synthesis of factor VIII/ IX inhibitors. The development of inhibitors can occur idiopathically or as a result of conditions that manipulate the immune system such as malignancies, pregnancy, autoimmune disorders (e.g Lupus erythematosus and rheumatoid arthritis) and some medications like interferon-ą. Theses acquired forms of the disease, mostly appear in adulthood despite the classic form of the disease and of note, their clinical presentation of them is slightly different with the joints being least involved.