Hemophilia is a blood clotting disorder that causes the blood to not clot completely. When a person has hemophilia, the bleeding that occurs in his body will last longer than normal. What causes hemophilia? Check out the following reviews.
Genetic mutation, the main cause of hemophilia
Basically, hemophilia is a disease caused by a genetic mutation. The mutated gene usually varies, depending on the type of hemophilia you have.
In type A hemophilia, the mutated gene is F8. Meanwhile, the mutated F9 gene triggers type B hemophilia.
The F8 gene plays a role in making a protein called clotting factor VIII. Meanwhile, the F9 gene plays a role in the production of clotting factor IX. Clotting factors are proteins that work in the process of blood clotting.
When there is a wound, these proteins will protect the body by coagulating bleeding. That way, the damaged blood vessels are protected and the body doesn’t lose too much blood.
The mutated F8 or F9 gene triggers the production of clotting factor VIII or IX that is not normal, even the number is greatly reduced. Too little clotting factor will result in poor blood clotting ability. Finally, the blood fails to clot completely when bleeding occurs.
How is hemophilia passed from parents?
The main cause of hemophilia is a genetic mutation, and this is usually hereditary. This genetic mutation occurs only on the X sex chromosome.
Every human being is born with 2 sex chromosomes. Each chromosome is inherited from the father and mother. Girls get two X (XX) chromosomes, one each from their mother and father. While a boy (XY) will have an X chromosome from his mother and a Y chromosome from his father.
Reporting from the site Hemophilia of Georgia, most women who are born with the genetic mutation generally do not show signs or symptoms of hemophilia. Women who do not have these symptoms are usually referred to as carriers or carriers of the mutated gene. A carrier not necessarily have hemophilia.
For example, a woman is born with an X chromosome from her mother who does not contain the problematic gene. However, he got the X chromosome from his father who had hemophilia.
The girl will not suffer from hemophilia because the normal genes from the mother are much more dominant than the problematic genes from the father. So, these girls will only become carriers of genes that have the potential to cause hemophilia.
However, these women have the possibility of passing on the mutated gene to their children in the future. The chance that the child will become a carrier or suffer from hemophilia will depend on the sex of the child later.
Basically, there are 4 main keys that explain the risk of a child being born with hemophilia, namely:
- Boys born to fathers with hemophilia, will not have hemophilia
- Daughters born to fathers with hemophilia, will be carriers
- If a carrier has a boy, the boy’s chance of developing hemophilia is 50%
- If a carrier has a daughter, the chance for the girl to become a carrier is 50%
Because hemophilia affects only the X chromosome, and men only have 1 X chromosome, men generally do not become carrier or carrier. Unlike women who have two X chromosomes, so they have the opportunity to be normal, carrier, or have hemophilia.
The father has hemophilia, the mother does not have hemophilia and is not a carrier
If the father has a mutated gene and has hemophilia, but all of the genes owned by the mother are healthy and normal, the son will certainly not develop hemophilia or become a carrier.
However, if you have a girl, it is likely that her daughter will be born with the gene that causes hemophilia, aka carrier.
Father does not suffer from hemophilia, carrier mother
In this case, if the baby gets the Y chromosome from the father, the baby will be male. Boys will get the X chromosome from their mother who is a carrier. However, the chances of the boy getting the problematic gene from the mother (become carrier) is about 50%.
Meanwhile, baby girls born to healthy fathers will also get a healthy X chromosome from their father. However, because the mother is a carrier, the girl also has a 50% chance of becoming a carrier of the gene that causes hemophilia.
Father has hemophilia, mother is a carrier
If a father with hemophilia passes the Y chromosome to the baby, the child will be born as a boy. The baby boy will get the X chromosome from the mother who is the carrier.
If the X chromosome inherited from the mother contains a genetic mutation, the baby boy will develop hemophilia. Conversely, if the mother inherits a healthy X chromosome, the boy will have normal blood clotting genes, aka healthy.
Things are slightly different for baby girls. A baby girl is certain to get the X chromosome from a father who has hemophilia, so he will become a carrier of the mutated gene.
If the mother who is a carrier passes on the healthy X chromosome, the baby girl will only become the carrier. However, if the inherited X chromosome has the mutation in the gene that causes hemophilia from the mother, he will develop hemophilia.
So, fathers who suffer from hemophilia and mothers who are carriers have a bigger chance of:
- 25% to deliver baby boys with hemophilia
- 25% to give birth to healthy baby boys
- 25% to deliver baby girls who are carriers
- 25% to deliver baby girls with hemophilia
Can hemophilia occur in the absence of heredity?
After understanding the explanation above, you may wonder whether this disease can occur even if a person does not have parents who have hemophilia? The answer, still you can. However, these cases are very rare.
Hemophilia that occurs in the absence of heredity is called acquired hemophilia. This condition can appear at any time when a person has reached adulthood.
According to the site Genetic Home ReferenceAcquired hemophilia occurs when the body makes special proteins called autoantibodies. These autoantibodies will attack and inhibit the performance of clotting factor VIII.
Usually, the production of these autoantibodies is associated with pregnancy, abnormalities in the immune system, cancer, or allergic reactions to certain drugs. However, in half of the cases of acquired hemophilia it is not known the exact cause.
If you have a history of this disease and are planning a pregnancy, it’s a good idea to consult a doctor. Your doctor may recommend several tests. That way, your pregnancy can be more anticipated.