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Christmas Disease Is The Condition You Need To Know About This Festive Season

That wasn't very Christmassy.


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Red blood cells floating down a vein with proteins.
Blood's coagulation process involves many components, one of which is a protein called factor IX. Image credit: Tatiana Shepeleva/

There is a condition called Christmas disease that affects thousands of people around the world, but it’s not as jolly as it may sound. We're using this festive period to spread some awareness of this rare and little-known disease. 

Christmas disease is also known as hemophilia B or IX hemophilia. Its name has little to do with the holiday season, instead stemming from the name of the first person to be officially diagnosed with the condition in 1952, a young British boy called Stephen Christmas.


What is Christmas disease?

It describes a disorder where a person's blood does not clot properly, which can lead to life-threatening bleeding, but it differs subtly from classic hemophilia. When you cut, scrape, or puncture your skin, it should start to ooze liquid blood. Very quickly, however, the blood will undergo a coagulation process that turns it into a gel and eventually a clot. This process involves many components, one of which is a protein called factor IX

People with the Christmas disease produce little or none of these proteins because they have an inherited mutation of the gene that codes for factor IX. As a result, they can experience prolonged, sometimes life-threatening, bleeding after an injury and bruise easily. They can even experience spontaneous bleeding, like nosebleeds, blood in pee, and bleeding in the joints.

Other forms of hemophilia, which involve other types of anti-hemophilic factors, are more prolific with hemophilia B representing just 15 percent of total cases. 

Is Christmas disease inherited?

Over 60 percent of cases are inherited, so the disease can run in families. Undoubtedly the most famous instance of this is Queen Victoria of England (1837 to 1901). Her youngest son, Leopold, is now known to have lived with hemophilia B and at least two of her five daughters, Alice and Beatrice, were carriers. Due to the incestuous “intermingling” of royal families in Europe at the time, the condition also found its way into the ruling families of Russia, Spain, and Germany during the 19th and 20th centuries.


The condition overwhelmingly mainly affects men. This is because the gene responsible for factor IX is carried on the X chromosome, which males have one of (XY) and females have two of (XX). 

Males have a higher chance of being stuck with an X chromosome that doesn’t carry the gene. If a female inherits a mutated gene on one of their X chromosomes, they will not develop hemophilia B as the other X chromosome can still code for some factor IX. Women with the mutated X chromosome will be a carrier though and around 15 to 20 percent of them will suffer from some mild problems with blood clotting.

Many families with a history of hemophilia choose to have their children tested early on, which involves a screening test and clot test. 

Is there a treatment for Christmas disease?

People can be treated at times of severe bleeding with an intravenous infusion of factor IX and/or blood transfusions. However, this only provides temporary relief. 


Fortunately, new treatments are on the horizon. In November 2022, the US Food and Drug Administration (FDA) authorized the first gene therapy to treat adults with hemophilia B. Dubbed etranacogene dezaparvovec (Hemgenix), it’s a one-time gene therapy that introduces the gene for factor IX using a virus. 

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions. 


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