Hemophilia A

Published on February 27, 2020   31 min

Other Talks in the Series: Periodic Reports: Advances in Clinical Interventions and Research Platforms

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I'm Snejana Krassova, I'm the head of the Medical Affairs Hematology at Bayer. I'm immunohematologist by training and been in the industry of hemophilia for over 17 years. Today, we're going to talk about hemophilia A specifically, and the innovations that have been made in this field.
So, hemophilia A is a genetic deficiency in clotting factor VIII. As many of you are aware, it causes increased bleeding and usually affects males. In the majority of cases, it's an inherited X-linked recessive trait. So, it's an X-linked disorder, the mother is a carrier of the developed gene. This results in people bleeding longer after any injury, after bruising, and increased risk of bleeding inside joints or vital organs. There is no long-term cure yet. Treatment and prevention of bleeding episodes is done primarily by replacing the missing clotting factor.
So, as it's been described, hemophilia A indeed is a rare disease. Approximately 400,000 people live with hemophilia- a majority of women with hemophilia A. There is also hemophilia B. Hemophilia A happens one in 5,000 male births; whereas, hemophilia B happens in one of 30,000 male births. So, again, the major issue is the bleeding into the joints, muscles, and internal organs. The classification of hemophilia is based on the factor levels. In this case, for hemophilia A factor level VIII and the percentage of the activity of factor VIII in blood. The severe form is less than one percent; and then the moderate form, one to five percent; mild form, 5-40. The obviously, the normal levels, it's 50-150 percent in the unaffected individual. So, again, it's a genetic mutation and it's passed from mother, the gene on the X chromosome. So, the daughters can be carriers. In the very rare cases, a mutation, what we call lyonization, the woman can give a mutation also called lyonization. In this case, a woman can get hemophilia. This is very, very rare and the woman will have both X chromosomes affected. As I was saying, it's very rare but it does happen from time to time. The majority of affected individuals are males. The incidence of new mutations is about 50 percent, which means half of the families with a boy with hemophilia will have a history of hemophilia, and half of them will not, which would be out of two and quite unexpected for the parents.