Advancing understanding of hemophilia A in women

News / Women’s Health
By Mary Anne Beaudette and Anne Craig

Dr. Paula James explores why genetic carriers of hemophilia A often experience abnormal bleeding

KHSC physician Dr. Paula James has revealed women who are carriers of hemophilia A, an inherited bleeding disorder, experience abnormal bleeding in about 30 per cent of cases. Dr. James is working to unravel the mystery as to why this abnormal bleeding, including nosebleeds, heavy periods, and bleeding following childbirth, occurs.

Dr. James’ study showed that, compared to the control group, the Factor VIII response in Hemophilia A patients, including those with normal clotting factor levels, was both significantly reduced and shorter-lived. These results were correlated with those that had higher levels of abnormal bleeding.

“It’s long been assumed that women who carry this gene don’t have bleeding symptoms but we now know that isn’t true," says Dr. James, who is also a Clinician Scientist with the Kingston Health Sciences Research Institute and a Professor at Queen's University. "Some patients have low levels of clotting Factor FVIII in their blood, and for those that don’t, there must be other contributing factors. It’s a challenging problem because it has led to their bleeding symptoms being dismissed and not treated properly.”

The research results suggest that the women may not be able to generate and sustain a high enough increase in Factor VIII in response to bleeding, likely because of the FVIII mutation that causes hemophilia A. Abnormal bleeding can lead to iron deficiency, which causes fatigue, sleep disturbance, and impaired learning and work performance.

“It’s a huge quality of life issue for these women. We need to understand this disease better in order to treat it properly. While we still don’t have all the answers, this discovery adds significantly to our understanding of why, even when they have normal clotting factor levels, women who are carriers of hemophilia A have abnormal bleeding,” says Dr. James.

The study was published in Blood Advances.