Updated by: Arabinda Naik
It is commonly called as bleeder’s disease. It is sex linked disease first studied by John Cotto. This trait is inherited in the British royal family and has been passed on to other royal housed across Europe through Queen Victoria. Due to absence of antihaemophilic globulin or plasma thromboplastin in the blood the patient bleeds for hours. As a result of continuous bleeding, the patient may die blood loss. Haemophilia is caused by a sex-linked recessive gene h located in the X chromosome. The gene fails to produce necessary factor for quick clotting. A female become haemophilic only when the X chromosome carry the gene h (XhXh). such female dies before birth. A female possessing only one allele for haemophilia XXh appear to be normal as the other X is dominant as there is normal h allele. Such female is called carriers. In case male the recessive gene h on X chromosome expresses itself as Y chromosome is devoid of any h allele XhY.
Haemophilia A
It is most common type of haemophilia. It is characterized by the absence of antihaemophilic globulin.
Haemophilia B
Results from defect in Plasma Thromboplastic component. (PTC )