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noun he·mo·phil·ia \ˌhē-mə-ˈfi-lē-ə\

Simple Definition of hemophilia

  • medical : a serious disease that causes a person who has been cut or injured to keep bleeding for a very long time

Source: Merriam-Webster's Learner's Dictionary

Full Definition of hemophilia

  1. :  a sex-linked hereditary blood defect that occurs almost exclusively in males and is characterized by delayed clotting of the blood and consequent difficulty in controlling hemorrhage even after minor injuries

Did You Know?

The dreaded disease known as hemophilia is the result of an inherited gene, and almost always strikes boys rather than girls (though mothers may pass the gene to their sons). Since the blood lacks an ingredient that causes it to clot or coagulate when a blood vessel breaks, even a minor wound can cause a hemophiliac to bleed to death if not treated. Bleeding can be particularly dangerous when it's entirely internal, with no visible wound, since the person may not be aware it's happening. Queen Victoria transmitted the hemophilia gene to royal families all across Europe; the hemophilia of a young Russian prince played a part in the downfall of the Russian czars. Today, hemophiliacs take drugs that stop the bleeding by speeding coagulation, and hemophiliac life expectancies in developed countries are almost as long as the average.

Origin and Etymology of hemophilia

New Latin

First Known Use: 1872

Other Genetics Terms

Medical Dictionary


noun he·mo·phil·ia

Medical Definition of hemophilia

  1. :  a tendency to uncontrollable bleeding; especially :  a hereditary, sex-linked blood disorder occurring almost exclusively in males that is marked by delayed clotting of the blood with prolonged or excessive internal or external bleeding after injury or surgery and in severe cases spontaneous bleeding into joints and muscles and that is caused by a deficiency of clotting factors Hemophilia is inherited as an X-linked recessive trait in which the mother must pass on a copy of the defective gene to a male child, and more rarely, both parents must pass on copies of the defective gene to a female child.

—see hemophilia a, hemophilia b; compare von willebrand disease

Variants of hemophilia

or chiefly British



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a very small amount

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