What is Haemophilia B

Updated at: Apr 08, 2016
What is Haemophilia B

Haemophilia B is a genetic bleeding disorder. Read more to know everything you need to know about this bleeding disorder.

Tanushree Singh
Blood DiseasesWritten by: Tanushree SinghPublished at: Apr 06, 2016

Haemophilia B is a genetic bleeding disorder caused by missing or defective blood clotting factor IX. Factor IX is a clotting protein and without enough factor IX, the blood fails to clot properly in order to control bleeding.


haemophilia B



Although, the condition is a genetic disorder, which means that it is usually passed down from people who have the condition to their children, however around 33% of cases are caused by changes in genes.


While the condition is not that common, it can affect anyone regardless of their race or ethnicity. According to statistics from the US Centers for Disease Control and Prevention, haemophiliaB is four times less common than haemophilia A and occurs in around 1 in every 5,000 live births. So what causes haemophilia B?

Common causes of haemophilia B

Haemophilia B is caused by adefective factor IX which is linked with the X chromosome. Men and people who have family history of bleeding disorders have a higher risk for haemophilia B.


Men are at a higher risk for the condition as they have only one X chromosome. If the factor IX gene is defective or missing in a boy child’s X chromosome, he will develop Haemophilia B. Most of the people who have haemophilia B around the world are men.


On the other hand, women have two copies of the X chromosome.If the factor IX gene on one chromosome is defective or missing, the gene on the other can  make the required amount of factor IX.
When a woman has a defective factor IX gene, she is considered a carrier. Her sons will have 50% chance of having haemophilia and her daughters will have 50% chance of carriers.

Haemophilia symptoms

The most common symptoms of haemophilia B include bleeding as the main symptom. Usually the bleeding symptoms appear during circumcision of a child or when the child starts crawling or walking. The severity of the symptoms can vary from one child to another. Other most common symptoms include bruising, nosebleeds, painful bleeding into joints, blood in urine or stools, and excess bleeding from cuts.

Treatment of the condition

Doctors usually start with coagulation study including a series of tests to diagnose the condition. Family members may also get tested to confirm the disorder. Once the diagnosis is complete the doctor may proceed with the treatment by replacing the missing clotting factor through factor IX concentrates.


The treatment depends upon the severity of the bleeding, region of bleeding and the patient’s weight and height. People with severe cases of haemophilia B may need infusions regularly.



Image Source : Getty

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