Hemophilia is an inherited bleeding disorder. Children with hemophilia have problems with bleeding because of low levels or complete absence of specific proteins, called “factors,” in their blood that are necessary for prevention of excessive bleeding.
In the United States, about 20,000 people have hemophilia. People of all races and economic groups are equally affected. Each year, about 400 babies are born with hemophilia. The most common forms of hemophilia result from deficiencies of clotting factor proteins, factor VIII and factor IX. Both Factor VIII and Factor IX are necessary to form a clot.
Hemophilia types A and B are inherited bleeding diseases passed on to children from defective genes located on the X chromosome. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). Males (XY) have hemophilia when the gene for clotting factor VIII (Hemophilia A) or clotting factor IX (Hemophilia B) on the single X chromosome is affected.
A female carrier of hemophilia has the hemophilia gene on one of her X chromosomes and the normal gene on her other X chromosome. When a woman who is a carrier of the hemophilia gene becomes pregnant, there is a 50% chance that the child will get the X chromosome with the hemophilia gene. If the gene is passed onto the daughter, she will be a carrier.
If the father has hemophilia and the mother does not carry the hemophilia gene, then none of her sons will have hemophilia disease (because the mother has donated a normal X chromosome and the father has donated a normal Y chromosome). However, in this scenario, all of the daughters will be carriers because the mom donates her normal X chromosome and the father has donated his abnormal X chromosome with the abnormal gene present.
In about one-third of the children with hemophilia, there is no family history of the disorder. A new gene mutation, it is believed may be the cause of the disorder.
A complete medical and family history is taken and a physical examination is performed. Your child’s physician may perform numerous blood tests including clotting factor levels, a complete blood count (CBC) and possibly DNA testing.
The most common symptom of hemophilia is excessive, uncontrollable bleeding. Patients with hemophilia do not bleed faster than normal children; they bleed for a longer time.
The severity of symptoms in children with hemophilia depends on the severity of the disease.
Severe hemophilia is when factor VIII or factor IX clotting factor activity is less than 1%.
Moderate hemophilia is when factor VIII or IX clotting factor activity is 1–5%.
Mild hemophilia is when factor VIII or IX clotting factor activity is 6–40%.
Other symptoms of hemophilia include:
While a cure for hemophilia is not currently available, the disorder may be managed effectively by doing the following: