NB: Haemophilia appears to be the English and Australian spelling, while the US uses Hemophilia. Please feel free to correct me if I'm wrong about that.
A genetic disease best known for it's affects on members of Europe's royal families in the 18th and early 19th centuries. Damon Courtenay, the son of Australian author Bryce Courtenay also suffered from severe haemophilia. Bryce's exceptionally moving book April Fools Day describes Damon's fight with both haemophilia and HIV/AIDS.
The following is quoted from Peter Jones' Living With Haemophilia . 4th Ed. Oxford UP 1995
I doubt anyone will ever look it up, but the researcher in me demands the full bibliographic listing.
Haemophilia is a genetically inherited bleeding disorder.
There are two types of hemophilia: haemophilia A, or clotting factor VIII deficiency, and haemophilia B, or clotting factor IX deficiency. The degree of deficiency varies from mild to severe. About one third of hemophilia cases occur with no previous family history; this is called sporadic haemophilia. It is assumed that these cases are the result of genetic mutation.
Due to the genetic pattern of inheritance, the disorder generally affects males only. About one third of cases occur with no previous family history. Women with a haemophilic gene are called carriers. Each daughter of a carrier mother has a 50% chance of being a carrier. Each son has a 50% chance of having haemophilia. Carriers are usually, but not always, symptom-free.
Von Willebrand Disease (vWD) is another more common hereditary bleeding disorders. Patients with vWD have diminished production of von Willebrand factor or produce von Willebrand factor that does not function normally. This disorder affects both males and females equally, and the symptoms are usually not as severe as those of a person with haemophilia, but do include bleeding from the nose, mouth or intestinal tract. Von Willebrand disease is probably the most common of the inherited clotting disorders although it is generally the least severe.
The incidence of haemophilia A in the world population is one in ten thousand males. In its severe form, incidence is one in sixteen thousand. There is no known geographical variation in the incidence of either haemophilia A or hemophilia B. It has been calculated that worldwide there are approximately 350 000 people with severe or moderate haemophilia A. Haemophilia B is five times less common than haemophilia A.
The severity of haemophilia is dependent on the level of clotting activity of factor VIII or factor IX in the blood. (see Figure 1).
Range of factor VIII and factor IX activity as a % of normal factor activity in blood and in number of ius per ml of whole blood
- Over 200% or 2iu
- Higher levels found in pregnancy
- 50-200% or 0.5-2 iu
- Normal range of Factor VIII or Factor IX activity
- 25-49% or 0.25- 0.45 iu
- Approximately one third of carriers have levels in low normal or subnormal range
- 6-24% or 0.06- 0.24 iu
- Level above which unusual bleeding after injury is unlikely.
- 1-5% or 0.01 – 0.05 iu
- Moderate Haemophilia
- Less than 1% or 0.01 iu
- Severe Haemophilia