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Explainer: Why Is Hemophilia B Called Christmas Disease?

The bleeding disorder hemophilia B goes by an alternate name all because of a 5-year-old boy.

a mittened hand holds a heart hanging from a snowy Christmas tree

When you hear the term “Christmas disease,” you might wonder if it is somehow related to the holiday.

But this alternate name for hemophilia B came about because of the first hemophilia B patient: 5-year-old Stephen Christmas. It was 1952 when the Canadian boy was diagnosed thanks to coagulation researchers, Rosemary Biggs and Robert McFarlane.

Until then, there was just one known type of hemophilia, a genetic condition that causes problems with the way blood clots and puts patients at risk of serious bleeding. A classic case of hemophilia meant that the person lacked an important blood protein called clotting factor VIII (8).

But Biggs and McFarlane discovered that while Christmas had the bleeding problems associated with hemophilia, he did not have factor VIII (8) deficiency. Christmas had a different deficiency in blood clotting proteins and was lacking clotting factor IX (9). The researchers named the condition Christmas disease after the young patient. It would later be called hemophilia B and a factor VIII deficiency became known as hemophilia A.

Seventy years after the discovery of hemophilia B, much has changed for patients. For a long time, people who had hemophilia A and B died young because effective treatments didn’t exist. That dramatically changed with factor replacement therapy. Today, there are a number of medicines available to the bleeding disorder community and lifespans have greatly improved.

This year, CSL Behring has been celebrating these important medical advances with a photography exhibit called Portraits of Progress. And on November 22, CSL Behring made an important announcement about a new treatment for hemophilia B.

You might have guessed that if there are factors numbered VIII (8) and IX (9) there are others. In fact, there are 10+ clotting factors, each with its own job to do. Hemophilia B is less common than hemophilia A, but still affects thousands.

Both factor VIII deficiency (hemophilia A) and factor IX deficiency (hemophilia B) are the result of mutations in the genes that encode coagulation factors VIII and IX respectively and prevent the blood from clotting properly. Because they are distinct and separate conditions, they require different treatments. Today, treatment options continue to grow thanks to the ongoing efforts of researchers, scientists and the hemophilia community.

See the virtual exhibition Portraits of Progress.

See CSL Behring’s press release about a new treatment.