Hemophilia A


Classic hemophilia, which is due to a profound deficiency in the activity of clotting factor VIII. Affected individuals suffer hemorrhage into joints and muscles, easy bruising, and prolonged bleeding from wounds. The disease is inherited as an X-linked trait, so males are affected and females carry the gene. Treatment involves administration of blood products that introduce clotting factor VIII and replace lost blood. Use of contaminated blood products exposed many people with hemophilia to HIV infection in the 1980s and 1990s. Hemophilia A has affected the Russian royal house and the descendants of Queen Victoria.

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  • Hemophilia B

    Hemophilia due to deficiency of coagulation factor IX in the blood, which results in prolonged oozing after minor and major injuries, tooth extractions, or surgery. There is renewed bleeding after the initial bleeding has stopped. The gene for hemophilia B is on the X chromosome, so males are affected and females carry the gene. About […]

  • Hemophilia carrier

    A female carrying a mutant gene for hemophilia on one of her two X chromosomes and a normal allele on her other X chromosome. Hemophilia carriers have concentrations of clotting factor VIII or IX of about 50% of normal and, hence, decreased ability to clot their blood. However, if they have a clinical bleeding tendency, […]

  • Hemoptysis

    Spitting up blood or blood-tinged sputum from the respiratory tract. Hemoptysis occurs when tiny blood vessels that line the lung airways are broken. Hemoptysis can be harmless such as from irritated bronchial tubes with bronchitis, or be serious such as from cancer of the lung.

  • Hemorrhage

    Bleeding or the abnormal flow of blood. A hemorrhage may be “external” and visible on the outside of the body or “internal,” where there is no sign of bleeding outside the body. Bleeding from a cut on the face is an external hemorrhage. Bleeding into the spleen or liver are examples of internal hemorrhage. The […]

  • Hemorrhage, subarachnoid

    Bleeding within the head into the space between two membranes that surround the brain. The bleeding is beneath the arachnoid membrane and just above the pia mater. (The arachnoid is the middle of three membranes around the brain while the pia mater is the innermost one.) The subarachnoid space is a potential space. It is […]


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