MEDICAL SURFARI: WHAT CAUSES BLUE-BLOOD DIESEASE?

Actually, there is nothing blue about hemophilia, an inherited blood-clotting disorder causing easy bruise ability and abnormal bleeding. Hemophilia got its name as blue blood disease because it tended to run in certain royal families in Europe.

More than 15,000 people in the United States have hemophilia---they are missing or have a low supply of one of the factors needed for normal blood clotting. The increased tendency to bleeding usually becomes apparent early in life, and if not treated, it may lead to severe anemia or even death. Injuries that are so trivial as to generally be unnoted may lead to large bruises of the skin and soft tissues. People with this disorder are at higher risk of bleeding after dental work, surgery, or trauma. They may also develop spontaneous internal bleeding without any apparent precipitating event. They tend to be at risk for repeated bleeding in joints causing swelling and impaired function that may lead to chronic joint problems and loss of range of motion.

Not everyone has the same degree of hemophilia. About 15 percent of persons with this trait have an increased risk for bleeding, but rarely have spontaneous bleeding. About 25 percent of people with this disorder have mild hemophilia and in fact their condition may be so mild that it may go undetected until bleeding occurs after trauma or surgery.

Hemophilia is a genetic disorder and this trait is carried by females on one of their X chromosomes. There is a 50 percent chance that a woman who is a carrier of this trait will pass this on to her male child who will develop the disorder. There is also a 50 percent chance that a woman with this trait may pass the hemophilia gene to her daughter, making her daughter a carrier of this trait. Males who inherit this trait on the X chromosome develop this disorder because they have only one X chromosome. Females who inherit the trait on one X chromosome become carriers of the trait since they have a second X chromosome that usually effectively overrides the defective one. However, some female carriers have low blood factor levels resulting in a tendency toward easy bruising and excessive bleeding.

People with hemophilia require replacement of the deficient blood factors responsible for normal blood clotting. There is only a very small amount of this special clotting factor in each donated unit of blood, consequently, this must be extracted from blood donated by many different individuals. This increases one's chance of acquiring an HIV infection and/or hepatitis.

Recently, scientists have used genetic engineering to "artificially" create this deficient blood factor necessary for normal blood clotting. This has been possible through an advanced method called recombinant DNA technology. "Recombinant" means that the DNA, or genetic material, from several different types of organisms has been broken up and spliced together then reintroduced into functional cells that in turn reproduce the necessary blood factor. Recombinant Factor VIII was first approved by the U.S Food and Drug Administration (FDA) in 1993, and in early 1997 the FDA licensed a Recombinant Factor IX product. These advances are very encouraging and ideally with further advances in genetic engineering, one day the genetic defect may be able to be repaired for people with this disorder.

World Wide Web Resources

The National Hemophilia Foundation

http://www.hemophilia.org/

The National Hemophilia Foundation (NHF) is dedicated to the cures of inherited bleeding disorders and the prevention and treatment of their complications through education, advocacy, and research.

Hemophilia Home Page

http://www.web-depot.com/hemophilia/AutoSite/AutoSite.cgi/19970328.013255.21769 3/26/98

This site gives you answers and teaches what hemophilia is, how common it is, how you get it, symptoms, and treatments, in an easy to understand format.

The World Federation of Hemophilia

http://www.wfh.org/

This web site is generously sponsored with an unrestricted educational grant from Genetics Institute and is dedicated to maintaining and advancing services worldwide. Search their extensive library for a wealth of material on hemophilia for families, healthcare workers, students, and the general public.

Dr. Scott Gibbs is a neurosurgeon and editor-in-chief of Mosby's Medical Surfari. You may e-mail questions to him at drgibbs@semissourian.com or write in care of the Southeast Missourian, P.O. Box 699, Cape Girardeau, Mo., 63701.