Haemophilia

Haemophilia is an inherited bleeding disorder in which deficient or defective clotting proteins impair blood-clot formation, causing prolonged bleeding and bleeding into joints or muscles.

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Coagulation: Coagulation is the process by which blood forms a clot to limit bleeding. Haemophilia disrupts this process by reducing the activity of specific clotting factors.
Haemophilia A: Haemophilia A is an inherited bleeding disorder caused by deficient or defective factor VIII. It is the most common form of haemophilia.
Factor replacement therapy: Factor replacement therapy treats clotting-factor deficiency by administering the missing factor. It can prevent or control bleeding in haemophilia A and B.
John Conrad Otto: John Conrad Otto was an American physician whose 1803 account described a hereditary bleeding tendency in some families. His report is an early medical description of haemophilia's inherited pattern.
Intracranial hemorrhage: Intracranial hemorrhage is bleeding within the skull, including bleeding in or around the brain. It is a dangerous haemophilia complication that requires urgent assessment.
Factor VIII: Factor VIII is a blood-clotting protein that acts as a cofactor in the coagulation cascade. Deficiency or dysfunction of factor VIII causes haemophilia A.
Haemophilia B: Haemophilia B is an inherited bleeding disorder caused by deficient or defective factor IX. It produces a similar bleeding pattern to haemophilia A through a different factor deficiency.
Emicizumab: Emicizumab is a bispecific antibody that brings activated factor IX and factor X together to support clotting. It provides prophylaxis for haemophilia A, including some cases with factor VIII inhibitors.
Queen Victoria: Queen Victoria was monarch of the United Kingdom from 1837 to 1901 and carried a haemophilia-associated variant. Her descendants spread the variant through several European royal families.
Blood transfusion: Blood transfusion is the transfer of blood or blood components into a person's circulation. Before safe factor concentrates, repeated transfusions were among limited options for severe bleeding.