Haemophilia is a rare inherited bleeding disorder in which blood doesn’t clot normally because it lacks or has low levels of certain proteins (clotting factors). There are 13 types of clotting factors, and these work with platelets to help the blood clot. Bleeding may occur spontaneously or following injury. If you have haemophilia, you may bleed for a longer time after an injury than you would if your blood clotted normally.
Haemophilia is inherited bleeding disorder. However, about 30 percent of people with haemophilia have no family history of the disorder. In these people haemophilia is caused by a genetic change (spontaneous mutation).
There are three forms of haemophilia: haemophilia A, haemophilia B and haemophilia C.
Haemophilia A is the most common type and is caused by a deficiency in clotting factor VIII.
Haemophilia B (also called Christmas disease) is caused by a deficiency of clotting factor IX.
Haemophilia C is a mild form and is caused by a deficiency of clotting factor XI.
Everyone has two sex chromosomes, one from each parent. A female inherits an X chromosome from her mother and an X chromosome from her father. A male inherits an X chromosome from his mother and a y chromosome from his father. Haemophilia inheritance depends on your type of haemophilia.
Haemophilia A or B: the gene that causes them is located on the X chromosome, so it can’t be passed from father to son. Haemophilia A or B almost always occurs in boys and is passed from mother to son through one of the mother’s genes. Most women with the defective gene are simply carriers and experience no signs or symptoms of haemophilia. Women can experience bleeding symptoms if their factor VIII or IX is moderately decreased.
Haemophilia C: this disorder can be passed on to children by either parent. Haemophilia C can occur in girls and boys.
In extremely rare cases, haemophilia can develop after birth, which is called “acquired haemophilia.” This is the case in people whose immune system forms antibodies that attack the IX or VIII blood clotting factors.
Signs and symptoms
Signs and symptoms of haemophilia vary, depending on your level of clotting factors. Haemophilia can vary in its severity, depending upon the particular type of mutation (genetic defect). The degree of symptoms depends upon the levels of the affected clotting factor. Severe disease is defined as <1% factor activity, 1% to 5% factor activity is moderate disease, and greater than 5% factor activity constitutes mild disease. Those with mild haemophilia may only bleed excessively in response to injury or trauma. With severe haemophilia (A or B), bleeding begins at an early age and may occur spontaneously.
- Unexplained and excessive bleeding from cuts or injuries, or after surgery or dental work
- Many large or deep bruises
- Unusual bleeding after vaccinations
- Pain, swelling or tightness in your joints
- Bloody urine (haematuria) and blood in stool
- Frequent nosebleeds (epistaxis) without a known cause
The following symptoms constitute an emergency and should be treated right away:
- Sudden pain, swelling and warmth in large joints, such as knees, hips and shoulders
- Severe headache
- Sudden pain, swelling in your arm and leg muscles
- Frequent vomiting
- Bleeding from an injury, especially if you have a severe form of haemophilia
- Extreme tiredness
- Prolonged headache
- Double vision
The majority of patients with haemophilia have a known family history of the condition. However, about one-third of cases occur in the absence of a known family history. For people with a family history of haemophilia, it’s possible to determine during pregnancy if the fetus is affected by haemophilia. However, the testing poses some risks to the fetus.
If there is no known family history of haemophilia, it’s usually only diagnosed when a child begins to walk or crawl. They may experience joint bleeds or easy bruising. Mild haemophilia may only be discovered later, usually after an injury or a dental or surgical procedure.
A series of blood tests can identify which part or protein factor of the blood clotting mechanism is defective if an individual has abnormal bleeding episodes. Specific tests for the blood clotting factors can then be performed to measure factor VII or factor IX levels and confirm the diagnosis. If such tests are abnormal, other blood tests are carried out to determine the amounts of factors VIII and IX in the blood. These tests help doctors diagnose the type of haemophilia and its severity.