What Is Hemophilia?
Hemophilia is an inherited bleeding disorder in which a person lacks or has low levels of certain proteins called clotting factors, and as a result the blood does not clot properly. There are 13 types of clotting factors, and these work with platelets (small blood cells that form in bone marrow) to help the blood clot. According to the World Federation of Hemophilia (WFH), about 1 in 10,000 people are born with this disease (WFH, 2012).
People with this condition bleed easily and the blood takes a longer time to clot. People with hemophilia can experience spontaneous or internal bleeding and often have painful, swollen joints due to bleeding into the joints.
This rare but serious condition can have life-threatening complications.
There are three forms of hemophilia: hemophilia A, hemophilia B, and hemophilia C.
Hemophilia A is the most common type of hemophilia, and is caused by a deficiency in clotting factor VIII. According to the National Heart, Lung, and Blood Institute (NHLBI), nine out of 10 people with hemophilia have hemophilia A (NHLBI, 2011) .
Hemophilia B (also called Christmas disease) is caused by a deficiency of clotting factor IX.
Hemophilia C is a mild form of the disease that is caused by a deficiency of Factor XI blood clotting factor. People with this rare type of hemophilia often do not experience spontaneous bleeding; hemorrhaging typically occurs after trauma or surgery.
Hemophilia is an inherited genetic condition. This condition is not curable, but it can be treated to minimize symptoms and future health complications.
In extremely rare cases, hemophilia can develop after birth, which is called “acquired hemophilia.” This is the case in people whose immune system forms antibodies that attack the IX or VIII blood clotting factors.
What Causes Hemophilia?
Bleeding is stopped by a process within the body known as the coagulation cascade. Blood platelets coagulate (gather together at the wound site) to form a clot. Then the body’s clotting factors work together to create a more permanent plug in the wound. A low level of these clotting factors, or the absence of them, causes bleeding to continue.
Hemophilia and Genetics
Hemophilia is an inherited genetic condition, meaning it is passed down through families. It is caused by a defect in the gene that determines how the body makes blood-clotting factors VIII or IX. These genes are located on the X chromosome, making hemophilia an X-linked recessive disease.
Each person inherits two sex chromosomes from their parents. Women have two X chromosomes; men have one X and one Y chromosome. Males inherit an X chromosome from their mother, and a Y chromosome from their father. Females receive an X chromosome from each parent. Because the gene that causes hemophilia is located on the X chromosome, this means that fathers cannot pass the disease to their sons. A woman with one faulty X chromosome has a 50 percent chance of passing the faulty gene to her children, male or female. Women who has a faulty hemophilia gene on one her X chromosomes is typically called a carrier, meaning that she may pass the disease onto her children, but does not have the disease herself. This is because she has sufficient blood clotting factors from her normal X chromosome to avoid serious bleeding issues. However, women who are carriers often have an increased risk for bleeding (NHLBI, 2011).
Conversely, men with a faulty X chromosome may pass it on to their daughters, making them carriers of the faulty gene. A female must have the distorted gene on both of her X chromosomes in order to have hemophilia. However, this is very rare.
Risk Factors for Inheriting Hemophilia
Hemophilia A and B are more common in males than females because of the genetic transmission.
Hemophilia C is an autosomal inherited form of the disease, meaning that it affects males and females equally. This is because the genetic defect that causes this type of hemophilia is not related to sex chromosomes. According to the Indiana Hemophilia and Thrombosis Center (IHTC), this form of the disease most commonly affects people of Ashkenazi Jewish descent, but may affect other ethnic groups as well. In the U.S., hemophilia C affects about 1 in 100,000 people. (IHTC)
What Are the Symptoms of Hemophilia?
The extent of your symptoms depends on the seriousness of your factor deficiency. People with a mild deficiency may bleed in the case of trauma; however, people with a severe deficiency may bleed for no reason (spontaneous bleeding). In children with hemophilia, these symptoms may occur around age two.
Spontaneous bleeding can cause the following signs and symptoms:
- blood in the urine
- blood in the stool
- deep bruises
- large, unexplained bruises
- unexplained bleeding
- excessive bleeding
- frequent nosebleeds
- pain in the joints
- tight joints
- irritability (in children)
When to See a Doctor
The following symptoms constitute an emergency and should be treated right away:
- severe headache
- vomiting repeatedly
- neck pain
- blurred or doubled vision
- extreme sleepiness
- continuous bleeding from injury
If you’re pregnant, it’s important that you see a doctor if you experience any of the above symptoms.
How Is Hemophilia Diagnosed?
Hemophilia is diagnosed through a blood test. The doctor will remove a small sample of blood from your vein and measure the amount of blood-clotting factor present. The sample is then graded to determine how severe the blood-clotting factor deficiency is.
- Mild hemophilia is indicated by a clotting factor of between five and 30 percent.
- Moderate hemophilia is indicated by a clotting factor of between one and five percent.
- Severe hemophilia is indicated by a clotting factor value of less than one percent.
How Is Hemophilia Treated?
People with hemophilia A are treated with a prescription hormone. This hormone is called desmopressin, and is administered by injection into a vein. This medication works by stimulating the factors responsible for the process of blood clotting.
Hemophilia B is treated by infusing the affected person’s blood with donor clotting factors. Sometimes, the factor may be given in synthetic form (recombinant clotting factors).
Hemophilia C is treated by plasma infusion. The infusion works to stop profuse bleeding. The deficient factor responsible for hemophilia C is not available as a medication in the U.S.; it is only available in Europe.
Physical therapy may be used to help rehabilitate people with joints damaged by hemophilia.
Possible Long-Term Health Complications
Complications of hemophilia include:
- joint damage
- deep bleeding internally
- increased risk of developing hepatitis when receiving donor blood
Hemophilia is passed from a mother to her child. When you are pregnant, there is no way of knowing whether your baby has the condition. However, if the eggs are fertilized in a clinic (in-vitro fertilization), they can be tested for the condition. Then, only the eggs without hemophilia are implanted.