hemophilia B is a rare inherited bleeding disorder caused by insufficient levels of a blood protein called factor IX (or factor 9). It is the second most common type of hemophilia, occurring in about 1 in 25,000 male births.
Factor IX is a blood clotting factor that promotes healing and helps the body seal wounds. Without it, the body will have difficulty effectively stopping blood flow to the site of a wound, injury, or bleeding. As a result, people with hemophilia B tend to bruise easily and bleed for prolonged periods of time.
Other names for hemophilia B include factor IX deficiency, Christmas disease, and Royal disease. The “Christmas Sickness” is named in honor of Stephen Christmas, the first person recorded in medical literature to suffer from the disease.
The name “Royal Disease” stems from the most famous example of this genetic disorder being passed down from generation to generation. Queen Victoria’s family passed the disease on to various descendants of the royal family, including members of Germany, Spain and Russia.
This article will discuss the symptoms and causes of hemophilia B and review the diagnosis process, treatment options, and prognosis of the disease.
Types of hemophilia
There are many factors involved in the process of forming a blood clot. The type of hemophilia you may have depends on which clotting factor you lack. Insufficient levels of factor VIII, factor IX, and factor XI are the most common.
The three main forms of hemophilia are:
- Hemophilia A: Caused by a deficiency of factor VIII, this is the most common type, accounting for nearly 85% of all cases.
- Hemophilia B: Caused by a deficiency of clotting factor IX, this is the second most common type of hemophilia.
- Hemophilia C: Caused by a deficiency of factor XI, this is the rarest type of hemophilia.
What are the symptoms?
The symptoms of hemophilia largely depend on the amount of factor IX (FIX) in the blood. Some people may not experience their first attack until adulthood, while others don’t notice symptoms during infancy or childhood.
Early symptoms of hemophilia in infancy include:
- Muscle bleeding and deep bruising, sometimes first discovered after routine vitamin K injections after birth
- Prolonged bleeding after baby’s heel is punctured to draw blood for newborn screening test
- Prolonged bleeding after circumcision
- Bleeding in the scalp or brain after using a vacuum or vacuum cleaner pliers During delivery, or after general hardship delivery
Other general symptoms of hemophilia B include:
- Bleeding from a joint or muscle, causing pain and swelling (hemoarthrosis)
- Unusual bleeding after injury or surgery
- easy bruising
- frequent nosebleeds
- blood in the urine
- Bleeding after dental surgery
- unexplained bleeding events
- Gastrointestinal (GI) and urinary tract bleeding
Symptoms of hemophilia B vary from person to person. Generally, the higher your FIX level, the milder your symptoms. If the FIX level is between 6% and 49% of normal FIX in plasma, it is considered a mild case and you are more likely to experience bleeding only after a serious injury, trauma or surgery.
In many cases, people with mild hemophilia B don’t know they have the disease and only find out after prolonged bleeding from injury, surgery, or tooth extraction. Women with mild hemophilia often experience menorrhagia (menorrhagia) and can bleeding after giving birth.
Even a small amount of FIX can prevent life-threatening bleeding events. People with 1%–5% FIX in their blood or with moderate hemophilia B may experience bleeding or spontaneous bleeding after injury.
If you have less than 1% FIX in your blood, you are at risk for life-threatening bleeding complications and are considered to have severe hemophilia B. People with severe hemophilia B can bleed after an injury, and may often have spontaneous episodes of bleeding into their joints and muscles.
Causes and Risk Factors
Hemophilia B is an inherited disease. It primarily affects men, although female carriers of the disease may experience mild bleeding due to reduced levels of factor IX (FIX) in the blood.
Hemophilia B is caused by a defect in the F9 gene located on the X chromosome. The F9 gene is just one gene involved in the coagulation process. It is responsible for making and activating factor IX. Mutations in the F9 gene are inherited in 70% of cases and spontaneously occur in 30% of cases.
Hemophilia B is an X-linked genetic disease, which means that the transmission of the disease is related to the mother’s carrier status. Mothers who carry the hemophilia gene have a 50 percent chance of transmitting the gene in each pregnancy. Males who inherit the pathogenic variant will be affected, and daughters who inherit the pathogenic variant will be carriers.
A man with hemophilia B will pass the gene for the disease to all his daughters, but not to his sons, because the man has received his Y chromosome. A woman with the disease (or carrier) will pass the gene on to about half of her offspring—whether they’re male or female.
Most people have an inherited or inherited form of hemophilia B, but there is another rare form of hemophilia B that can be acquired with age. This non-inherited form of hemophilia B develops if the body starts to produce antibodies against its own factor IX protein. The reason why this happens in rare cases is not known.
How to Diagnose Hemophilia B
Hemophilia B is diagnosed after your healthcare provider has documented your bleeding events, family history of bleeding and genetics, and laboratory tests. Specialized coagulation tests are needed to confirm the diagnosis.
A blood test is used to measure how long it takes your blood to form a clot. Laboratory studies for suspected hemophilia B include complete blood counts, coagulation Studies and Factor IX (FIX) Assays.
The following FIX levels indicate severity (levels calculated from the percentage of FIX in plasma):
- Mild: Greater than 5%–49% of normal
- Moderate: 1%–5% of normal
- Severe: less than 1% of normal
Genetic testing can also be done to look for specific mutations in the F9 gene that cause hemophilia B to confirm the diagnosis.
New collaboration aims to make genetic testing more accessible
What are the treatment options?
There is no cure for hemophilia B, but people with hemophilia and their families can learn how to prevent harm and use their own clotting factor treatment products at home.
Primary treatments for hemophilia B include prevention (to avoid injury), develop a plan to manage bleeding events, and replace factor IX therapy. There are two types of clotting factor concentrates that can be given intravenously (by IV, intravenously).
- Plasma-Derived Factor Concentrates: Lyophilized Coagulation Factors from Human Plasma
- Recombinant Factor Concentrates: Recombinant plasma factors, without human plasma or albumin
Hemophilia treatment is usually done in a comprehensive hemophilia treatment center (HTC).These specialized units consist of a multidisciplinary team that includes doctors who specialize in the treatment of blood disorders, called hematologist And health care providers who specialize in physical medicine and rehabilitation for people with bleeding disorders, including nurses, social workers, and physical therapists.
Prognosis of hemophilia B
Until 1970, the life expectancy for people with all types of hemophilia was about 12 years, but thanks to advances in medical therapy and better medical care, hemophilia B has become a chronic disease that many people can manage properly for life.
People with hemophilia still have about 10 years less life expectancy than people without hemophilia, but ultimately life expectancy and risk of medical complications depends on the severity of your disease, access to care, and whether you have other medical conditions .
Hemophilia B is an inherited disorder that can cause minor and major bleeding episodes. This condition is due to a lack of a blood clotting factor called factor IX.
This condition can be diagnosed with a blood test. As part of the diagnosis process, you or your child may also have genetic testing for the gene mutation that causes hemophilia B.
While there is no cure for hemophilia B, there are treatments available (such as factor IX replacements) that can help reduce the severity and frequency of bleeding episodes and improve your quality of life. Having hemophilia B can mean you need to take care to avoid injury, but it is possible to live a healthy, normal life with the condition.
Advances in medicine have enabled people with hemophilia B to live full and productive lives. Some people with hemophilia experience frequent bleeding episodes, while others experience infrequently.
No matter which category you fall into, combining injury avoidance, prompt management of even minor injuries, and clotting factor supplementation is a safe and effective way to reduce the likelihood of serious bleeding events and other complications.