A disorder linked to a recessive gene on the X-chromosome in which the blood clots much more slowly than usual, resulting in extensive bleeding from even minor injuries. The gene is passed by women to their male children and the disorder is seen almost exclusively in boys.
An inherited disorder of blood coagulation which results in prolonged bleeding even after minor injury. There is a deficiency of factor VIII, an essential clotting factor in the coagulation cascade the complex series of biochemical events that leads from injury of the wall of a blood vessel to the formation of a blood clot that checks bleeding. Haemophilia is a sex linked recessive disorder (though a small number of cases arise by spontaneous mutation). Thus, if females carry the disease, one-half of their sons will be affected and one-half of their daughters will be carriers. The sons of male haemophiliacs are unaffected, but one-half of their daughters will be carriers.
Haemophilia is an inherited bleeding disorder resulting from a deficiency of a blood protein called factor VIII, crucial for blood clotting. Haemophiliacs, who are typically male, experience recurring bleeding episodes, often into their joints. These bleedings can happen spontaneously or after an injury.
The absence of factor VIII is a result of a defective gene, and this genetic condition follows a pattern of sex-linked inheritance. Affected males pass on the gene to their daughters, who become carriers of the condition, rather than passing it on to their sons. Some of the sons of carrier females may be affected by haemophilia, and some of the carrier daughters may also pass on the gene to their offspring. Haemophiliacs often have close family members, such as uncles, brothers, or grandfathers, who are also affected. However, in about one-third of cases, there is no family history of haemophilia.
The severity of the disorder varies significantly among individuals. However, episodes of bleeding are often painful and, if not promptly treated, can result in deformity of the knees, ankles, and other joints. Even minor injuries or procedures such as tooth extraction can cause excessive bleeding. Internal bleeding may lead to the presence of blood in the urine or the development of extensive bruises.
Haemophilia is diagnosed through blood-clotting tests, and in a fetus, it can be identified using amniocentesis or chorionic villus sampling. To manage bleeding, factor VIII concentrates can be administered through infusions. Individuals with a severe form of the disorder might require regular intravenous injections of factor VIII as a preventive measure.
Many individuals with haemophilia can maintain an active lifestyle, but they should be cautious to avoid the risk of injury. Contact sports like football are not recommended, but activities such as swimming and walking can be beneficial. Female relatives of individuals with haemophilia should seek genetic counselling before planning a pregnancy.