Difference Between Hemophilia A & Hemophilia B
Hemophilia is a rare disorder affecting almost exclusively males. It is an inherited disease, meaning it is passed on from parents to children through the genes. Inheritance is X-linked recessive. This means that the female with two X chromosomes acts as a carrier and only the male offspring suffer from the disease. In females when one of the two X chromosomes is defective, the other will compensate but since men have only one X chromosome, they will have the disease if that chromosome is defective. Hemophilia A, also called classic hemophilia and hemophilia B or Christmas disease are the two common types of this disease.
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Incidence
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Statistically, the difference between Hemophilia A and Hemophilia B is that A is five times more common than B. Worldwide, Hemophilia A occurs once in 4,000 male births where as B occurs once in 20,000 male births.
Genes Related to Hemophilia
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Hemophilia A is caused by a mutation occurring in the F8 gene whereas hemophilia B is caused by a mutation in the F9 gene. Mutations to these genes cause abnormal production of certain coagulation factors.
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Pathophysiology
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Whenever there is bleeding due to injured blood vessels, it is stopped by the clotting mechanism of the blood. There are various factors called "blood clotting factors" involved in the mechanism of clotting. In hemophilia, there is a deficiency in one or more of the clotting factors that results in blood not clotting as efficiently as it should. The result is prolonged bleeding. Here, the difference between hemophilia A and hemophilia B is that in "A" there is a deficiency or non-function of the critical co-factor "factor VIII" where as in hemophilia B, there is a deficiency of the essential clotting factor, "factor IX."
Signs and Symptoms
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The signs and symptoms of hemophilia depend on the severity of the disorder. In mild disorders, it may not manifest unless there is a major injury. However, in individuals with severe cases even minor injuries and bruises can cause bleeding. The bleeding can be internal or external.
Signs of external bleeding include:
1. Prolonged bleeding from a small cut.
2. Bleeding from the nose without reason.
3. Profuse bleeding from the mouth after an injury or an accidental bite.Signs and symptoms of internal bleeding include:
1. Blood in urine and stools.
2. Swelling and tightness due to bleeding in the knees, elbows or other joints. The joint becomes tender and eventually there is a temporary loss of movement.
3. Bleeding in the brain, which is a serious complication, may result in headache, vomiting, weakness of the limbs, double vision, a change in behavior and convulsions.
Treatment
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Clotting factor concentrates are given to patients with hemophilia. Previously, demand therapy, which is giving clotting factor after a bleeding episode, was the norm. However, prophylactic therapy, that is, giving clotting factor on a regular basis to prevent bleeding is gaining acceptance. The concentrates made from human blood or recombinant clotting factors are used in the treatment. The third generation recombinant clotting factor is animal protein free and hence extremely safe. Hemophilia A is treated with "factor VIII" concentrate and hemophilia B with factor IX concentrate.
Desmopressin is a medicine that can be used in the mild form of hemophilia A. It stimulates the body to produce factor VIII. This cannot be used for Hemophilia B.
Potential
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Although once considered a devastating disease, with recent advances, individuals with either hemophilia A or B can lead relatively normal and healthy lives with a normal life span.
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