What is hemophilia?

What is HemophiliaMany people as the question what is hemophilia?

Hemophilia is a bleeding disorder that slows down the blood clotting process. People who have hemophilia often have longer bleeding after an injury or surgery. People who have severe hemophilia have spontaneous bleeding into the joints and muscles. Hemophilia occurs more commonly in males than in females.

The two most common types of hemophilia are hemophilia A (also known as classic hemophilia) and hemophilia B (also known as Christmas disease). People who have hemophilia A have low levels of a blood clotting factor called factor eight (FVIII). People who have hemophilia B have low levels of factor nine (FIX).

The two types of hemophilia are caused by permanent gene changes (mutations) in different genes. Mutations in the FVIII gene cause hemophilia A. Mutations in the FIX gene cause hemophilia B. Proteins made by these genes have an important role in the blood clotting process. Mutations in either gene keep clots from forming when there is an injury, causing too much bleeding that can be difficult to stop.

Hemophilia A is the most common type of this condition. One in 5,000 to 10,000 males worldwide have hemophilia A. Hemophilia B is less common, and it affects 1 in 20,000 to 34,500 males worldwide.


What Is Von Willebrand Disease?

Von Willebrand disease, also known as vWD, is the most common hereditary blood clotting (coagulation) abnormality described in humans - in other words, it is the most common inherited bleeding condition. Von Willebrand disease, however, can also result from other medical conditions. The patient suffers from extended or excessive bleeding. The bleeding may sometimes damage internal organs, and even cause death, although this is rare.

VWD may arise from a quantitative or qualitative deficiency of vWF (von Willebrand factor), a multimeric protein that is required for platelet adhesion - i.e., patients either have low levels of that protein in their blood, or the protein does not work properly. VWF is a vital component in the blood clotting process. Patients take longer to form blood clots; when they are cut it takes longer for them to stop bleeding.

When a blood vessel is injured, small blood cell fragments called platelets will normally clump together to plug the hole in the blood vessel and stem the bleeding. VWF is a glue-like substance that helps the platelets stick together and form a blood clot. VWF also carries clotting factor VIII, a vital protein in the blood clotting process. Clotting factor VIII is either missing or faulty in patients who have hemophilia, or some other clotting disorder.

Although von Willebrand disease is much more common than hemophilia, it is usually milder.

According to the NIH (National Institutes of Health), USA, 1 in every 100 to 1,000 people in the USA is affected. While hemophilia affects males, VWD affects both sexes.

The condition is known to affect humans and dogs (especially Doberman Pinschers), and in very rare cases swine, cattle, horses and cats.

Other factors, including ABO blood groups may also influence the severity of the condition.

Von Willebrand disease treatment focuses on preventing or stopping bleeding episodes, mainly with medications. With proper treatment patients can lead normal and healthy lives.


Is hemophilia inherited?

Hemophilia is inherited in an X-linked recessive pattern. A condition is considered X-linked when gene mutation that causes it is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is enough to cause the condition. Since females have two X chromosomes, a mutation must be present in both copies of the gene to cause the hemophilia. Males are affected by X-linked recessive disorders much more frequently than females. A major characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

A female who is a carrier has a 1 in 2 (50 percent) chance to pass on her X chromosome with the gene mutation for hemophilia A or B to a boy who will be affected. She has a 1 in 2 (50 percent) chance to pass on her X chromosome with the normally functioning gene to a boy who will not have hemophilia.


How is hemophilia diagnosed?

Hemophilia A and B are diagnosed by measuring factor clotting activity. Individuals who have hemophilia A have low factor VIII clotting activity. Individuals who have hemophilia B have low factor IX clotting activity.

Genetic testing is also available for the factor VIII gene and the factor IX gene. Genetic testing of the FVIII gene finds a disease-causing mutation in up to 98 percent of individuals who have hemophilia A. Genetic testing of the FIX gene finds disease-causing mutations in more than 99 percent of individuals who have hemophilia B.

Genetic testing is usually used to identify women who are carriers of a FVIII or FIX gene mutation, and to diagnose hemophilia in a fetus during a pregnancy (prenatal diagnosis). It is sometimes used to diagnose individuals who have mild symptoms of hemophilia A or B.


What is the treatment for hemophilia?

There is currently no cure for hemophilia. Treatment depends on the severity of hemophilia.

Treatment may involve slow injection of a medicine called desmopressin (DDAVP) by the doctor into one of the veins. DDAVP helps to release more clotting factor to stop the bleeding. Sometimes, DDAVP is given as a medication that can be breathed in through the nose (nasal spray).

People who have moderate to severe hemophilia A or B may need to have an infusion of clotting factor taken from donated human blood or from genetically engineered products called recombinant clotting factors to stop the bleeding. If the potential for bleeding is serious, a doctor may give infusions of clotting factor to avoid bleeding (preventive infusions) before the bleeding begins. Repeated infusions may be necessary if the internal bleeding is serious.

When bleeding has damaged joints, physical therapy is used to help them function better. Physical therapy helps to keep the joints moving and prevents the joints from becoming frozen or badly deformed. Sometimes the bleeding into joints damages them or destroys them. In this situation, the individual may be given an artificial joint.

When a person who has hemophilia has a small cut or scrape, using pressure and a bandage will take care of the wound. An ice pack can be used when there are small areas of bleeding under the skin.

Researchers have been working to develop a gene replacement treatment (gene therapy) for Hemophilia A. Research of gene therapy for hemophilia A is now taking place. The results are encouraging. Researchers continue to evaluate the long-term safety of gene therapies. The hope is that there will be a genetic cure for hemophilia in the future.

Individuals who have hemophilia A and B are living much longer and with less disability than they did 30 years ago. This is because of the use of the intravenous infusion of factor VIII concentrate, home infusion programs, prophylactic treatment, and improved patient education.

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