Haemophilia.

“Hemophilia is a bleeding problem. People with hemophilia do not bleed any faster than normal, but they can bleed for a longer time. Their blood does not have enough clotting factor. Clotting factor is a protein in blood that controls bleeding.

People are born with hemophilia. They cannot catch it from someone like a cold. Hemophilia is usually inherited, meaning that it is passed on through a parent’s genes. The most common type of hemophilia is called hemophilia A. This means the person does not have enough clotting factor VIII (factor eight).

Hemophilia B is less common. A person with hemophilia B does not have enough factor IX (factor nine). The result is the same for people with hemophilia A and B; that is, they bleed for a longer time than normal.” Source: World Federation of Hemophilia.