Haemophilia B: Symptoms and treatment

You must have noticed that when you get injured, your blood turns to a gel, forming a blood clot. This mess your body is healing well. However, if you have haemophilia B, your blood won’t be able to clot properly and control bleeding. You will also get easily bruised if you have this genetic bleeding disorder. Also known as “Christmas disease,” haemophilia B is not common. Still, you should know about the disorder, its symptoms, and the treatment options. You should also know what makes it different from haemophilia A. On the occasion of World Haemophilia Day, which is observed on April 17 every year, we tell you all about it.

What is haemophilia B?

It is a rare genetic bleeding disorder where the blood does not have sufficient clotting factor IX, a protein important for normal blood clotting. “Without this factor, people with haemophilia B experience prolonged or spontaneous bleeding episodes, which can be triggered by injuries, surgeries, or even occur internally without obvious cause in severe cases,” explains haematologist Dr Vijay Ramanan.

It is the second most prevalent form of hemophilia, which has three main types. It is also known as Christmas disease, which is named after the first diagnosed case in 1952, Stephen Christmas, as per research published in StatPearls.

What are the symptoms of haemophilia B?

“The symptoms vary depending on the severity of the condition, but generally revolve around abnormal or too much bleeding,” says the expert.

• One of the most common signs is easy bruising, which often appears without obvious trauma.
• People may experience prolonged bleeding after injuries, cuts, procedures in a dental clinic, or surgery due to the deficiency of clotting factor IX.
• In moderate to severe cases, there can be spontaneous internal bleeding into joints such as knees, elbows, and ankles. “These joint bleeds can cause swelling, stiffness, warmth, and a lot of pain, leading to joint damage if you don’t get treated,” says Dr Ramanan.
• Bleeding into muscles and soft tissues.
• Blood in the urine or stool can indicate internal bleeding within the gastrointestinal or urinary tracts.
• In the most severe cases, life-threatening internal bleeding can occur in the brain, causing symptoms like severe headache, vomiting, seizures, or loss of consciousness.
• Female carriers or girls affected by it can experience heavy menstrual bleeding and excessive postpartum bleeding.

What causes haemophilia B?

It is a condition caused by mutations in the F9 gene located on the X chromosome, and responsible for producing clotting factor IX. Since the disorder is X-linked recessive, which means it is a pattern where a gene on the X chromosome causes a genetic condition, it mostly affects males. “Males have only one X chromosome, so inheriting the defective gene from their mother means they will develop the condition. Females have two X chromosomes, and are typically carriers when one of the X chromosomes carries the mutation,” explains the expert.

How is haemophilia B diagnosed?

Here’s how a doctor can confirm you have haemophilia B:

• The diagnosis of haemophilia B will begin with a thorough evaluation of your medical as well as family history of bleeding disorders.
• If unexplained or bleeding for a long time is observed, especially after injuries, surgeries, or during dental work, further testing is done.
• The first laboratory test usually performed is the activated partial thromboplastin time (APTT), which measures how long it takes the blood to clot.
• To confirm the diagnosis, a specific factor IX assay (a blood test to measure the activity of factor IX) is essential.

What is the difference between haemophilia A and B?

Both are inherited bleeding disorders, but they differ in the specific clotting factor that is deficient. “Haemophilia A is caused by a deficiency in factor VIII, while B is due to a deficiency in factor IX. The genes responsible — F8 and F9, respectively — are both located on the X chromosome, and both conditions follow an X-linked recessive inheritance pattern,” explains the expert. Hemophilia A is three to four times as common as hemophilia B, according to the US Centers for Disease Control and Prevention. Despite the difference, the symptoms are very similar. “People with hemophilia A also experience prolonged bleeding, easy bruising, and spontaneous joint bleeds,” says Dr Ramanan.

How to treat haemophilia B?

Currently, haemophilia B does not have a cure, but it can be managed.

• “The treatment focuses on replacing the deficient clotting factor IX to control and prevent bleeding episodes,” says the expert. Replacement therapy may help to improve the quality of life, as per research published in Biologics: Targets and Therapy. “Factor IX replacement therapy involves infusing synthetic, or plasma-derived factor IX into the bloodstream,” says the expert.
• Gene therapy is another option that introduces a healthy copy of the F9 gene into the liver cells, making the body produce its own factor IX.
• As part of supportive treatments, physiotherapy can help to preserve joint health, especially after joint bleeds. There are also iron supplements that may be suggested by your doctor to manage anemia.

“Family screening and genetic counseling are essential for management of haemophilia B,” says the expert.

Haemophilia B is a rare bleeding disorder, which is passed down from one parent to a child. There is no cure, but there are treatment options like the replacement therapy.