- Inherited: a disorder is transmitted from parents to their children. The disease is linked to a chromosome. Procreation consists in chromosomes of male and female that split and reunite to form a new cell. In humankind the new life is constituted by 23 chromosomes of which 22 are formed with ‘identical’ pairs (one side from each parent) and one with non- identical pair. This last one determines the gender and is symbolised as XX for female and XY for male.
- Autosomal inheritance: A gene - which is a small part of a chromosome - codes for a function of our body. The autosomal inherited gene is situated at one of the 22 identical chromosomes pairs.
- Sex linked inheritance: the inheritance of a gene is situated at the ‘gender’ chromosome pair (23).
- Autosomal dominant: one defective gene of one part of the 22 chromosomes pairs is sufficient to affect a person with the disease.
- Autosomal recessive: you need two defective genes, at each part of a pair of the 22 chromosomes, so that a person becomes affected by the disorder.
- Gender-linked: the malformation of the gene is linked to the X or Y part of the 23rd chromosome pair. The disease will mostly appear by male persons. Then, if the malformation is situated on the Y chromosome, only male have a Y chromosome. And if situated on the X-chromosome, women have two X-chromosomes; so one chromosome, that is not affected by the malformation can compensate. Whilst by male, if they have an X-chromosome with the malformation, they can’t compensate and therefore they express the disease. Haemophilia is an example of this. Only if a woman has a malformation of the two respective gens at each part of the 23rd chromosome pair, they will for sure express the disease. This can occur when the father is a person with haemophilia and the mother is a carrier.
- Carriers. In normal language everyone who ‘carries’ the ‘malformed gene’ should be called a carrier. But to distinguish on the one hand people who carry the malformed gene and express the disease (patients) and on the other hand people who carry the malformed gene but don’t express the disease, we call the last one ‘carriers’ and the others with the name of the disorder or patients.
- There are different bleeding disorders and each disorder has its specific treatment and sometimes even its specific expressing. (for more details see: 'Other genetic bleeding disorders')
- The most common bleeding disorder is the von Willerband disorder, due to the malformation of the gene that codes for the von Willebrand protein (vWF). We discern three types, of which type 3 is the most severe. (for more details see 'About von Willebrand disease')
- You also have the Platelet Function disorders.
- All bleeding disorders are autosomal recessive inherited except for haemophilia.
- Haemophilia is a sex linked inherited disorder. In haemophilia, male persons who carry the malformed gene, are always called persons with haemophilia. Female persons who carry the malformed gene on the contrary are never called persons with haemophilia. They are called carriers. Some of them express symptoms of the disorder although very rare are those with very severe expression. Those carriers who do have bleeding problems are called symptomatic carriers
