Incidence of Hemophilia
Hemophilia A affects about 1 in 10,000 people. That's about 3,000 Canadians.
Hemophilia affects people of all races and ethnic origins around the world. The most severe forms of hemophilia affect males almost exclusively.
Females can be seriously affected only if the father has hemophilia and the mother is a carrier. This is extremely rare. However, women who are carriers may have symptoms of mild hemophilia. The medical community is only now fully recognizing that carriers can also have bleeding problems.
Hemophilia in Families
Hemophilia is an inherited disorder, so children are affected right from conception. If parents know that there is a family history of hemophilia, then their children can be diagnosed in the womb, or at birth. However, when there is no family history, severe hemophilia will usually be diagnosed in the first year of life.
Myth: Boys always get hemophilia from their mothers
False. In most cases the gene responsible for hemophilia is transmitted from mother to son at the time of conception. However, some children are born with hemophilia even though their mothers are not carriers of hemophilia and no other family members are affected.
In about 3 cases in every 10, a son will be born to a family that has NO history of hemophilia. There are two reasons this might happen:
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An unknown family history of hemophilia
It is possible that hemophilia was in the family for generations, but went undetected because no male showed signs of increased bleeding or the female carriers did not have any sons before it was diagnosed. -
Hemophilia caused by a genetic mutation
Some cases of hemophilia are caused by a new, or "spontaneous," genetic mutation, which means that the gene carrying hemophilia was not present in any family member before a diagnosis was made in the child. No one knows why this happens, but a girl could be born with the mutated gene and then pass it on to her children. Boys can also have this spontaneous gene mutation.
Hemophilia in History
Hemophilia is sometimes referred to as "the royal disease" because it affected several members of the British and Russian royal families. One of the most famous cases was the family of Queen Victoria. Although she had no ancestors with the condition, her eighth child, Leopold, born in 1853 had a spontaneous mutation that caused the disorder, and two of her daughters were also carriers. The condition was transmitted through them to several royal families in Europe, including those in Spain and Russia.