Haemophilia is caused by an inherited genetic mutation, which mainly affects males.
A genetic mutation is a permanent alteration in the DNA sequence that makes up a gene. This means that some of the body's processes won't work in the normal way.
The type of mutation determines whether a family will experience mild, moderate or severe symptoms.
Chromosomes are strands of DNA. They contain a detailed set of instructions that control a wide range of factors, including how the body's cells develop and the baby's sex.
There are two types of sex chromosomes: the X chromosome and the Y chromosome. All humans have a pair of sex chromosomes. Men have an XY pair and women have an XX pair.
Boys inherit their X chromosome from their mother and their Y chromosome from their father. Girls inheritan X chromosome from each parent.
Haemophilia is inherited through a mutation in theX chromosome.
The chances of a child inheriting the haemophilia mutation depend on which of their parents has the mutated gene.
If a woman with the mutated X chromosome and an unaffected man have a baby, there's a:
In the last situation, the girl becomes a carrier of the mutated gene. This means she can pass it on to her children, but won't usually have any severe symptoms of haemophilia herself. However, some female carriers sometimes have bleeding problems, such as heavy periods.
If a man with haemophilia has a son with an unaffected woman, there's no chance the boy will get haemophilia. This is because he always inherits his X chromosome from his mother.
However, any daughters the man has will become carriers of the mutated haemophilia gene and may pass it on to their children.
If a woman with the mutated chromosome and a man with haemophilia have a baby, there's a:
This means it's possible for a female to have haemophilia, although it's very rare.
In some cases, a boy is born with haemophilia even though there's no family history of the condition.
In such cases, it's thought the mutation developed spontaneously in the boy's mother, grandmother or great-grandmother, but until then a male member of the family had never inherited the mutated gene.
Although family history is a strong indicator, some studies have shown there's no known family history of haemophilia in up to one-third of new cases.
Blood cells called platelets are very important for blood clotting. These cells have a sticky surface that allows them to clump together to stop the flow of blood.
Platelets also need clotting factors.These are proteins that form a "web" around the platelets, helping them to stay in place.
The mutated haemophilia gene means a child with the condition doesn't have enough clotting factors in their blood.
Several different clotting factors are present in the blood. They are numbered using roman numerals. For example, in haemophilia A there's not enough clotting factor VIII (8) in the blood. Inhaemophilia B, there's not enough clotting factor IX (9) in the blood.
Haemophilia is an inherited condition that affects the blood's ability to clot. Normally, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky
The symptoms of haemophilia vary, depending on how severe the condition is, but the main sign is prolonged bleeding. The symptoms of an intracranial haemorrhage include: severe headache, stiff neck, vomiting, a change in mental state such as confusion, etc.
Haemophilia is caused by an inherited genetic mutation that mainly affects males, due to the way it's passed from a parent to their child. A genetic mutation is a permanent alteration in the DNA sequence that makes up a gene.
Haemophilia can be diagnosed before, during or after birth if there's a family history of the condition. Several options are available to parents. If there's no family history of haemophilia, it's usually only diagnosed when a child begins to walk or crawl.
If your child is diagnosed with haemophilia, their recommended treatment plan will depend on how severe their haemophilia is. There are two main approaches to treatment: preventative treatment and on-demand treatment.
Some people who take blood clotting factor medication may develop certain antibodies in their immune system, known as inhibitors.This happens if the immune system starts to treat clotting factors as foreign objects (like germs) and tries to block their effects.
With treatment, most people with haemophilia can live a normal life. However, there are some things you'll need to be careful of. You should avoid contact sports such as rugby. You also need to be careful taking other medications, because some can interfere with your blood's ability to clot.