Haemophilia 101
Dr YLM explains a condition whereby blood clotting doesn’t happen.
I’ve heard about haemophilia and the fact that it is a genetic disease. What is haemophilia?
Haemophilia is a rare genetic bleeding disorder that is passed through the X chromosome. Everyone has two sex chromosomes – the X and the Y. If you are male, you have the XY chromosome. If you are female, you have the XX chromosome.
During conception, the mother contributes one of the two X chromosomes that she has to the child. The father gives either the X or the Y chromosome. An X produces a girl, a Y produces a boy. So you will have a 50-50 chance of getting a boy or a girl.
Contrary to popular belief, the sex of the child is mostly determined by the father. So it’s useless to blame the mother if the sex of your child doesn’t turn out to be the one you want!
Haemophilia is carried on the X chromosome. It is called an X-linked genetic disorder. A woman who is a carrier for haemophilia has the genetic mutation on one of her X chromosomes. She will have another non-mutated X chromosome which compensates for the defect in the other X. But these women still might have bleeding problems.
It is not uncommon for women who carry the haemophilia gene to have low levels of clotting factor and have bleeding problems.
A man who has haemophilia has the mutation on his sole X chromosome. He does not have another X chromosome to compensate for this defect, so in him, full-blown haemophilia will manifest.
So haemophilia only appears in men?
Mostly. One big historical case study was the Russian royal family, before they were all slaughtered in the early 20th century revolution. The men manifested the disorder, but the gene was carried throughout many royal families in Europe because they married each other.
Two-thirds of haemophilia cases are inherited. The other one third occurs spontaneously.
Because the haemophilia gene is an X-linked recessive (as opposed to dominant) gene, it will only manifest if you have no second X chromosome to counter this. So it will only manifest in men, or in women who have two defective X chromosomes.
So how does haemophilia manifest?
People who have haemophilia have little or no clotting factor. There are many different clotting factors, and these are needed to facilitate blood clotting.
There are two types of haemophilia: A and B. If you have haemophilia A, you have no or very little clotting factor VIII (8). About eight out of 10 people who have haemophilia have type A. If you have haemophilia B, you have no or very little clotting factor IX (9).
How haemophilia presents is based on your levels of clotting factors. If your clotting factor level is only mildly reduced, you may only bleed after surgery or trauma.
If your levels are very low, then you may even bleed spontaneously.
How does someone bleed spontaneously? You mean you can meet someone on the street, and he simply starts bleeding in front of you?
This is not haemorrhagic fever, so relax! You may, however, experience the following:
• Unexplained and excessive bleeding from cuts or injuries (such as when you fall down and scrape your knee).
• Excessive bleeding after surgery or dental work.
• Many large or deep bruises appearing on the arms and legs for no reason at all.
• Bleeding in your gums when you brush your teeth.
• Unusual bleeding after vaccinations.
• Pain, swelling or tightness in your joints (denotes bleeding into the joints, such as your knee joint).
• Blood in your urine or stool.
• Nosebleeds for no known reason.
• In infants, unexplained irritability.
Be very careful. You can even bleed inside your brain! In fact, if you experience a sudden headache, vomiting, double vision or neck pain, you should suspect this at once if you have haemophilia and rush to the hospital.
Is there any cure for haemophilia?
There is no cure. If you have mild haemophilia, you can have an injection of desmopressin hormone (DDAVP) which can stimulate the release of more clotting factors.
However, if you have moderate to severe haemophilia, you need to infuse the actual recombinant clotting factor that you are deficient in into your blood. Repeated infusions are often necessary.
If you have severe haemophilia, your doctor will recommend prophylaxis, meaning you inject the clotting factor before you even have a bleed.
Category: Features, Health alert
