Introduction - Hereditary Bleeding Disorders
Haemophilia is probably the best known example of the congenital blood clotting disorders, first described in Talmudic texts, and, in the early 20th Century, made famous by the Russian monk Rasputin and the ill-fated Tsarevich Alexis, who inherited his severe haemophilia indirectly from Queen Victoria.
The incidence of haemophilia A (coagulation factor VIII deficiency) is remarkably constant throughout the world, affecting between 7 and 10 per 100,000 males at birth, or roughly 3 to 5 individuals per 100,000 head of population. Haemophilia A and B (Factor IX deficiency) are both inherited as sex-linked recessive disorders. Males are therefore affected, while females are carriers of the defective gene.
If no preventive measures are taken, boys with severe haemophilia suffer repeated episodes of serious, spontaneous bleeding into muscles and major joints as often as 30 to 35 times a year. These haemorrhages occur primarily in weight-bearing joints -knees and ankles, almost as soon as affected boys start to walk. It is these repeated bleeds which cause progressive joint destruction, limitation of movement, deformity and crippling.
The cost of these disorders to society is enormous, not only because of the premature death of potentially useful members of society, but also because, if left untreated, patients end up hopelessly crippled; a burden upon society and their families, and their education is disrupted, resulting in unemployment and a sense of insecurity and inadequacy. Their sisters remain in an agony of doubt as to whether or not they are carriers, and will pass on the disorder to their sons.
Inherited deficiency of the nine or more other blood coagulation factors is relatively rare and often less clinically severe. The one exception is a group of bleeding disorders affecting both males and females, called von Willebrand's Disease (vWD), which is now known to be the commonest inherited bleeding disorder. The severe form (Type 3 vWD), which can resemble haemophilia in its intensity, is particularly common in Iran, due to the strong tradition of consanguineous marriage.