Table of contents:
- Genetic mutation, the main cause of hemophilia
- How is hemophilia passed from parents?
- Father has hemophilia, mother does not have hemophilia and he is not carrier
- Dad doesn't have hemophilia, mother carrier
- Father has hemophilia, mother is carrier
- Can hemophilia occur in the absence of heredity?
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 hemophilia type A, 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. This will protect the damaged blood vessels and prevent the body from losing 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 certainly results 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 Hemophilia of Georgia website, most women who are born with a genetic mutation generally do not show signs or symptoms of hemophilia. Women who do not have these symptoms are usually referred to as carrier or carriers of mutated genes. 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. Then, the girl will only become carrier of genes that could potentially cause hemophilia.
However, these women have the possibility of passing on the mutated gene to their children in the future. Her son's chances will be carrier or even suffering 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 become carrier
- If a carrier having a boy, the boy's chance of developing hemophilia is 50%
- If a carrier having a daughter, that girl's opportunity to become 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.
Father has hemophilia, mother does not have hemophilia and he is not 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. carrier.
However, if you have a girl, it is likely that her daughter will be born with the gene that causes hemophilia, aka carrier.
Dad doesn't have hemophilia, mother carrier
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 single mother 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 alone carrier, the girl also has a 50% chance of becoming carrier of the genes that cause hemophilia.
Father has hemophilia, mother is carrier
If a father with hemophilia passes the Y chromosome to the baby, the child will be born male. The baby boy will get the X chromosome from the mother who is carrier.
If the X chromosome that is passed on from the mother contains a genetic mutation, the baby boy will develop hemophilia. Conversely, if the mother inherits a healthy X chromosome, the baby boy will have normal blood clotting genes, aka healthy.
Things are a little different for baby girls. A baby girl is certain to get the X chromosome from a father who has hemophilia, so she will become carrier of the mutated gene.
If the mother is the one carrier lowering the healthy X chromosome, the baby girl is just going to be carrier. However, if the inherited X chromosome has the mutation in the gene that causes hemophilia from the mother, he will develop hemophilia.
So, the father who suffers from hemophilia and the mother who becomes carrier has a chance of:
- 25% to give birth to male babies with hemophilia
- 25% to give birth to healthy boys
- 25% to give birth to a baby girl who becomes carrier
- 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 Genetic Home Reference website, type hemophilia acquired (acquired) 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, half of the cases of hemophilia are of the type acquired the main cause is not known.
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.
