Gene therapy for hemophilia

Published on August 5, 2014   56 min

Other Talks in the Series: Gene Transfer and Gene Therapy

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The title of this talk is Gene Therapy for Hemophilia. My name is Katherine High, and I'm a professor of pediatrics at the University of Pennsylvania School of Medicine and an investigator of the Howard Hughes Medical Institute.
I'll begin by providing some background on blood coagulation and hemophilia. Hemophilia is the x-linked bleeding disorder that is caused by the absence of functional factor VIII, which is called hemophilia A, or factor IX, which is called hemophilia B. These diseases are clinically indistinguishable and were not separated in the laboratory until the 1950s. Both diseases are characterized by frequent bleeding episodes, primarily into the joints, also other soft tissues, and less frequently but more seriously, into critical closed spaces, such as the intercranial space. Hemophilia affects one in 5000 male births, with hemophilia A approximately five to six times more common than hemophilia B. And clinically the disease is divided into those who are severely affected who have less than 1% normal circulating levels of factor VIII or factor IX. Those who are moderately affected with levels of 1% to 5% and those who are mildly affected with levels of 5% or greater.
For individuals who have never seen a hemophilic knee bleed, you can see in this slide that the bleed can greatly distend the joint, and in fact, an untreated bleed will continue to bleed until the back pressure from the field that joint space exerts enough pressure to stop the bleeding. It's easy to imagine that this would be very painful and that repeated bleeds like this would result in a chronic arthropathy in the joint.