Hemophilia B (Christmas Disease)

Hemophilia B

Hemophilia B is a rare bleeding disorder that causes prolonged bleeding and easy bruising. It is also known as factor IX deficiency or Christmas disease1:

  • Four times less common than hemophilia A2
  • According to the CDC, hemophilia B occurs in approximately 1 in 25,000 male births; it rarely occurs in females3
  • Mainly an inherited disorder that results from a deficiency of a protein necessary to the blood-clotting process

In about 33% of cases, there is no family history of hemophilia B.1 Rather, the condition occurs as the result of a spontaneous gene mutation.1

Hemophilia B can be challenging to live with. Education and understanding the disease can help living with the disease easier to manage. Treatments for hemophilia B largely depend on the severity of symptoms. The condition requires attention, preparedness, and support from your healthcare team.4

What is Hemophilia B?

Hemophilia B is the second most common type of hemophilia.1 Like Hemophilia A, it is mainly an inherited disorder, but can be acquired in rare cases.

People born with hemophilia B have little to no factor IX, a protein that helps your blood clot. When blood can’t clot properly, it leads to prolonged bleeding and other signs and symptoms of hemophilia B.1

Hemophilia B has 3 levels of severity—mild, moderate, and severe.1 It is important to know the level, because the proper treatment depends on the severity of the condition. Usually, these treatments involve replacing the deficient or missing clotting factor IX.1

Mild hemophilia B

Mild hemophilia B usually causes problems with bleeding only after serious injury, trauma, or surgery. In many cases, mild hemophilia B is not discovered until there is unusual bleeding after an injury, surgery, or tooth extraction. Often, the first episode doesn’t occur until adulthood.

Moderate hemophilia B

People with moderate hemophilia make up about 15% of the hemophilia population.

  • Moderate hemophilia B tends to result in bleeding episodes after injuries
  • People with moderate hemophilia B may also have spontaneous bleeding episodes—bleeds that occur without obvious cause.
Severe hemophilia B

About 60% of the hemophilia B population has severe hemophilia.

  • People with severe hemophilia can have bleeding following an injury and may experience frequent spontaneous bleeding episodes, often into the joints and muscles.

There is no cure for hemophilia B, but with proper self-care and treatment, children and adults who have the disease can lead healthy, active lives.2


  1. Hemophilia B. National Hemophilia Foundation website. https://www.hemophilia.org/Bleeding-Disorders/Types-of-Bleeding-Disorders/Hemophilia-B. Accessed October 21, 2014.
  2. Fast facts. National Hemophilia Foundation website. http://www.hemophilia.org/About-Us/Fast-Facts. Accessed October 14, 2014.
  3. Hemophilia: data and statistics. Centers for Disease Control and Prevention website. http://www.cdc.gov/ncbddd/hemophilia/data.html. Updated August 26, 2014. Accessed October 14, 2014.
  4. Hemophilia B. PubMed Health website. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001566. Updated February 8, 2012. Accessed October 22, 2014.