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Definition

Hemophilia B is an inherited bleeding disorder caused by a lack of clotting factor IX in the blood. Without enough of this factor, the blood cannot clot properly to control bleeding.

Alternative Names

Christmas disease; Factor IX hemophilia; Bleeding disorder - hemophilia B

Causes

When you bleed, a series of reactions occurs in the body to help form blood clots. This process is called coagulation cascade. It involves special proteins called clotting factors or coagulants. You may have a higher risk of excessive bleeding if one or more of these factors is missing or isn’t working as it should.

Factor IX (nine) is one of these clotting factors. Hemophilia B is the result of the body’s inability to produce enough factor IX. Hemophilia B is caused by an X-linked recessive inherited trait, with the defective gene located on the X chromosome.

Women have two copies of the X chromosome. If the factor IX gene on one of the chromosomes doesn’t work, the gene on the other chromosome can do the work of producing enough factor IX.

Men only have one X chromosome. If the factor IX gene is missing on a boy’s X chromosome, he will have hemophilia B. For this reason, most people with hemophilia B are men.

If a woman has a defective factor IX gene, she is considered a carrier, which means that she can pass on this defective gene to her children. These women’s sons have a 50% chance of having hemophilia B, and their daughters have a 50% chance of being carriers.

All daughters of men with hemophilia are carriers of the defective gene.

Risk factors for hemophilia B include:

• Family history of bleeding

• Being male 

The severity of the symptoms can vary. Prolonged bleeding is the main symptom of the disease. Sometimes, it is observed for the first time when a baby is circumcised. Other bleeding problems usually appear when the baby starts crawling and walking.

Mild cases may pass unnoticed until a later age. Symptoms may appear for the first time after a surgery or injury. Internal bleeding can occur anywhere.

Symptoms may include:

• Bleeding within the joints, resulting in pain and swelling

• Blood in the urine or stool

• Bruising

• Bleeding in the digestive and urinary tracts

• Nosebleeds

• Prolonged bleeding from wounds, tooth extractions, and surgery

• Bleeding that starts without an apparent cause

If you are the first person in your family who has a suspected bleeding disorder, your health care provider will order a series of tests called a clotting study. Once the specific anomaly has been identified, other family members may need tests to diagnose the disorder.

Blood tests to diagnose hemophilia B include:

• Partial thromboplastin time (PTT) 

• Prothrombin time

• Factor IX activity in serum 

Treatment includes replacement of the missing clotting factor. You will receive factor IX concentrates. The amount you receive depends on:

• The severity of the bleeding

• The site of the bleeding

• Your height and weight 

To prevent a bleeding crisis, people with hemophilia and their families can be taught how to administer factor IX concentrates at home, at the first sign of bleeding. People with severe forms of the disease may require regular preventive infusions.

If you have severe hemophilia, you may also need to take factor IX concentrate before surgery or certain dental procedures.

You should receive the hepatitis B vaccine. People with hemophilia are more likely to get hepatitis as they may receive blood products.

Some people with hemophilia B may develop antibodies against factor IX. These antibodies are called inhibitors. The inhibitors attack factor IX, which makes it stop working. If this occurs, a synthetic clotting factor called VIIa may be administered. 

You can relieve the stress from the disease by joining a hemophilia support group. Sharing with others who have experiences and problems in common can help you not feel alone.

With treatment, most people with hemophilia B are able to lead relatively normal lives. 

If you have hemophilia B, you should have regular checkups with a hematologist.

Complications may include:

• Prolonged joint problems, which may require joint replacement

• Bleeding in the brain (intracerebral hemorrhage) 

• Blood clots from treatment

Contact your provider if:

• You have symptoms of a bleeding disorder

• A member of your family has been diagnosed with hemophilia B

• You have hemophilia B and plan to have children; genetic counseling is available

Genetic counseling may be recommended. Tests can identify women who are carriers of the hemophilia gene. 

Other tests can be done during pregnancy on a baby in their mother’s womb. 

Sources

Carcao M, Moorehead P, Lillicrap D. Hemophilia A and B. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 135.

Scott JP, Flood VH. Hereditary clotting factor deficiencies (bleeding disorders). In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 503.

Updated: Tuesday, January 25, 2022

English version reviewed by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. 

Translation and localization by: HolaDoctor, Inc.

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