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Hemophilia

Reviewed May 2010

What is hemophilia?

Hemophilia is a bleeding disorder that slows the blood clotting process. People with this condition experience prolonged bleeding or oozing following an injury, surgery, or having a tooth pulled. In severe cases of hemophilia, heavy bleeding occurs after minor trauma or even in the absence of injury (spontaneous bleeding). Serious complications can result from bleeding into the joints, muscles, brain, or other internal organs. Milder forms of hemophilia do not involve spontaneous bleeding, and the condition may not become apparent until abnormal bleeding occurs following surgery or a serious injury.

The major types of this condition are hemophilia A (also known as classic hemophilia) and hemophilia B (also known as Christmas disease). Although the two types have very similar signs and symptoms, they are caused by mutations in different genes. People with an unusual form of hemophilia B, known as hemophilia B Leyden, experience episodes of excessive bleeding in childhood but have few bleeding problems after puberty. Another form of the disorder, acquired hemophilia, is not caused by inherited gene mutations. This rare condition is characterized by abnormal bleeding into the skin, muscles, or other soft tissues, usually beginning in adulthood.

How common is hemophilia?

The two major forms of hemophilia occur much more commonly in males than in females. Hemophilia A is the most common type of the condition; 1 in 4,000 to 1 in 5,000 males worldwide are born with this disorder. Hemophilia B occurs in approximately 1 in 20,000 newborn males worldwide.

What genes are related to hemophilia?

Changes in the F8 gene are responsible for hemophilia A, while mutations in the F9 gene cause hemophilia B. The F8 gene provides instructions for making a protein called coagulation factor VIII. A related protein, coagulation factor IX, is produced from the F9 gene. Coagulation factors are proteins that work together in the blood clotting process. After an injury, blood clots protect the body by sealing off damaged blood vessels and preventing further blood loss.

Mutations in the F8 or F9 gene lead to the production of an abnormal version of coagulation factor VIII or coagulation factor IX, or reduce the amount of one of these proteins. The altered or missing protein cannot participate effectively in the blood clotting process. As a result, blood clots cannot form properly in response to injury. These problems with blood clotting lead to excessive bleeding that can be difficult to control. The mutations that cause severe hemophilia almost completely eliminate the activity of coagulation factor VIII or coagulation factor IX. The mutations responsible for mild and moderate hemophilia reduce but do not eliminate the activity of one of these proteins.

The other, rare form of this condition, acquired hemophilia, results when the body makes specialized proteins called autoantibodies that attack and disable coagulation factor VIII. The production of autoantibodies is sometimes associated with pregnancy, immune system disorders, cancer, or allergic reactions to certain drugs. In about half of cases, the cause of acquired hemophilia is unknown.

Related Gene(s)

Changes in these genes are associated with hemophilia.

  • F8
  • F9

How do people inherit hemophilia?

Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have hemophilia. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor IX, which is generally enough for normal blood clotting. However, about 10 percent of carrier females have less than half the normal amount of one of these coagulation factors; these individuals are at risk for abnormal bleeding, particularly after an injury, surgery, or tooth extraction.

Where can I find information about diagnosis or management of hemophilia?

These resources address the diagnosis or management of hemophilia and may include treatment providers.

  • Gene Review: Hemophilia A (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-a)
  • Gene Review: Hemophilia B (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-b)
  • Gene Tests: Hemophilia A (http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/clinical_disease_id/2342)
  • Gene Tests: Hemophilia B (http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/clinical_disease_id/2345)
  • Genetic Alliance (http://www.geneticalliance.org/site-search/results/hemophilia+taxonomy%3A13)
  • Lab Tests Online: Bleeding Disorders (http://labtestsonline.org/understanding/conditions/bleeding-disorders)
  • MedlinePlus Encyclopedia: Factor IX Assay (http://www.nlm.nih.gov/medlineplus/ency/article/003679.htm)
  • MedlinePlus Encyclopedia: Factor VIII Assay (http://www.nlm.nih.gov/medlineplus/ency/article/003678.htm)
  • MedlinePlus Encyclopedia: Hemophilia A (http://www.nlm.nih.gov/medlineplus/ency/article/000538.htm)
  • MedlinePlus Encyclopedia: Hemophilia B (http://www.nlm.nih.gov/medlineplus/ency/article/000539.htm)
  • National Heart, Lung, and Blood Institute: How is Hemophilia Diagnosed? (http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/diagnosis.html)
  • National Heart, Lung, and Blood Institute: How is Hemophilia Treated? (http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/treatment.html)
  • National Hemophilia Foundation: Hemophilia Treatment Centers (http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=203&contentid=385)

You might also find information on the diagnosis or management of hemophilia in Educational resources (http://ghr.nlm.nih.gov/condition/hemophilia/show/Educational+resources) and Patient support (http://ghr.nlm.nih.gov/condition/hemophilia/show/Patient+support).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about hemophilia?

You may find the following resources about hemophilia helpful. These materials are written for the general public.

  • MedlinePlus - Health information

    • Encyclopedia: Factor IX Assay (http://www.nlm.nih.gov/medlineplus/ency/article/003679.htm)
    • Encyclopedia: Factor VIII Assay (http://www.nlm.nih.gov/medlineplus/ency/article/003678.htm)
    • Encyclopedia: Hemophilia A (http://www.nlm.nih.gov/medlineplus/ency/article/000538.htm)
    • Encyclopedia: Hemophilia B (http://www.nlm.nih.gov/medlineplus/ency/article/000539.htm)
    • Health Topic: Hemophilia (http://www.nlm.nih.gov/medlineplus/hemophilia.html)

  • Additional NIH Resources - National Institutes of Health

    • National Center for Biotechnology Information: Genes and Disease (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?tool=bookshelf&call=bv.View..ShowSection&searchterm=hemophilia&rid=gnd.section.95)
    • National Heart, Lung, and Blood Institute (http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/)
    • National Human Genome Research Institute (http://www.genome.gov/20019697)

  • Educational resources - Information pages

    • Centers for Disease Control and Prevention: Hereditary Bleeding Disorders (http://www.cdc.gov/ncbddd/hemophilia/index.html)
    • Centre for Genetics Education (http://www.genetics.edu.au/Information/Genetics-Fact-Sheets/Haemophilia-Bleeding-Conditions-2-FS40)
    • Children's Hospital Boston (http://www.childrenshospital.org/az/Site1008/mainpageS1008P0.html)
    • Cincinnati Children's Hospital Medical Center (http://www.cincinnatichildrens.org/health/h/hemophilia/)
    • Cleveland Clinic (http://my.clevelandclinic.org/disorders/Hemophilia/hic_What_is_Hemophilia.aspx)
    • KidsHealth from the Nemours Foundation (http://kidshealth.org/parent/medical/genetic/hemophilia.html)
    • Madisons Foundation (http://www.madisonsfoundation.org/index.php?option=com_mpower&task=disease&diseaseID=84)
    • Mayo Clinic (http://www.mayoclinic.org/hemophilia/)
    • New York Online Access to Health (NOAH) (http://www.noah-health.org/en/blood/hemophilia/)
    • Orphanet (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=448)
    • The Merck Manual of Medical Information, Home Edition for Patients and Caregivers (http://www.merckmanuals.com/home/blood_disorders/bleeding_and_clotting_disorders/hemophilia.html)

  • Patient support - For patients and families

    • Canadian Hemophilia Society (http://www.hemophilia.ca/)
    • Family Village (http://www.familyvillage.wisc.edu/lib_hemp.htm)
    • Hemophilia Federation of America (http://hemophiliafed.org/)
    • National Hemophilia Foundation (http://www.hemophilia.org/)
    • National Organization for Rare Disorders (NORD) (http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/39/viewAbstract)
    • Resource list from the University of Kansas Medical Center (http://www.kumc.edu/gec/support/hemophil.html)
    • World Federation of Hemophilia (http://www.wfh.org/)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Reviews - Clinical summary

    • Gene Review: Hemophilia A (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-a)
    • Gene Review: Hemophilia B (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-b)

  • Gene Tests - DNA tests ordered by healthcare professionals

    • Gene Tests: Hemophilia A (http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/clinical_disease_id/2342)
    • Gene Tests: Hemophilia B (http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/clinical_disease_id/2345)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/ct2/results?cond=%22hemophilia%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=((Hemophilia%20A%5BMAJR%5D)%20OR%20(Hemophilia%20B%5BMAJR%5D))%20AND%20(hemophilia%5BTI%5D)%20AND%20review%5Bpt%5D%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%201800%20days%22%5Bdp%5D)

  • Online Books - Medical and science texts

    • Scriver's Online Metabolic and Molecular Bases of Inherited Disease (OMMBID): Hemophilia A: Deficiency of Coagulation Factor VIII (http://books.mcgraw-hill.com/getommbid.php?isbn=0071459960&template=ommbid&c=172)
    • Scriver's Online Metabolic and Molecular Bases of Inherited Disease (OMMBID): Hemophilia B: Factor IX Deficiency (http://books.mcgraw-hill.com/getommbid.php?isbn=0071459960&template=ommbid&c=173)

  • OMIM - Genetic disorder catalog

    • HEMOPHILIA A (http://omim.org/entry/306700)
    • HEMOPHILIA B (http://omim.org/entry/306900)

What other names do people use for hemophilia?

  • Hemophilia, familial
  • Hemophilia, hereditary

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about hemophilia?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding hemophilia?

autoantibody ; blood clotting ; blood coagulation ; cancer ; carrier ; cell ; chromosome ; clotting ; coagulation ; coagulation factors ; complication ; deficiency ; familial ; gene ; immune system ; inheritance ; injury ; joint ; mutation ; protein ; puberty ; recessive ; sex chromosomes ; sign ; soft tissue ; spontaneous ; surgery ; symptom ; tissue ; trait ; trauma ; X-linked recessive

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References

  • Bolton-Maggs PH, Pasi KJ. Haemophilias A and B. Lancet. 2003 May 24;361(9371):1801-9. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12781551?dopt=Abstract)
  • Colman, Robert W; Hemostasis and thrombosis : basic principles and clinical practice; 5th ed.; Philadelphia : Lippincott Williams & Wilkins, c2006. p887-904.
  • Franchini M. Acquired hemophilia A. Hematology. 2006 Apr;11(2):119-25. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16753853?dopt=Abstract)
  • Gene Review: Hemophilia A (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-a)
  • Gene Review: Hemophilia B (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hemo-b)
  • Giangrande P. Haemophilia B: Christmas disease. Expert Opin Pharmacother. 2005 Aug;6(9):1517-24. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16086639?dopt=Abstract)
  • Graw J, Brackmann HH, Oldenburg J, Schneppenheim R, Spannagl M, Schwaab R. Haemophilia A: from mutation analysis to new therapies. Nat Rev Genet. 2005 Jun;6(6):488-501. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15931172?dopt=Abstract)
  • Oldenburg J, El-Maarri O. New insight into the molecular basis of hemophilia A. Int J Hematol. 2006 Feb;83(2):96-102. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16513526?dopt=Abstract)
  • Plug I, Mauser-Bunschoten EP, Bröcker-Vriends AH, van Amstel HK, van der Bom JG, van Diemen-Homan JE, Willemse J, Rosendaal FR. Bleeding in carriers of hemophilia. Blood. 2006 Jul 1;108(1):52-6. Epub 2006 Mar 21. (http://www.ncbi.nlm.nih.gov/pubmed/16551972?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: May 2010
Published: May 21, 2012