Hemophilia is an inherited disease, most commonly affecting males, that is characterized by a deficiency in blood clotting. The responsible gene is located on the X chromosome, and since males inherit only one copy of the X chromosome, if that chromosome carries the mutated gene then they will have the disease.
Females have a second, usually normal, copy of the gene on their other X chromosome, so they capable of passing on the disease without experiencing its symptoms.
Hemophilia is an inherited disease that's characterized by bleeding beyond what would be expected in a normal individual. In other words, they have a deficiency in the ability to clot their blood. Often, we think of hemophilia [as] associated with males. Research Research. Clinical Research Resources ClinicalTrials. Click on the link to go to ClinicalTrials. Please note: Studies listed on the ClinicalTrials. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
Organizations Organizations. Organizations Supporting this Disease. Capitol St. Do you know of an organization? Living With Living With. Financial Resources Patient Services, Inc PSI provides financial support and guidance for qualified patients with specific chronic diseases.
PSI helps patients find solutions to the social and economic problems confronting patients with chronic conditions. Learn More Learn More. MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic. This website is maintained by the National Library of Medicine. The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers. NHLBI is part of the National Institutes of Health and supports research, training, and education for the prevention and treatment of heart, lung, and blood diseases.
NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them. In-Depth Information GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
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This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge. PubMed is a searchable database of medical literature and lists journal articles that discuss Hemophilia A. Click on the link to view a sample search on this topic.
Submit a new question I have severe hemophilia. See answer Have a question? References References. Genetics Home Reference. Hemophilia A. Drelich DA. Medscape Reference. Robert A Zaiden. Do you know of a review article? Share this content:. Close Copy Link. You May Be Interested In. How to Find a Disease Specialist. Tips for the Undiagnosed. Support for Patients and Families. Tips for Finding Financial Aid. Help with Travel Costs.
How to Get Involved in Research. Medical and Science Glossaries. Caring for Your Patient with a Rare Disease. FindZebra Diagnosis Assist Tool. Finding Funding Opportunities. Teaching Resources. Bleeding within a joint Hemarthrosis [ more ]. Percent of people who have these symptoms is not available through HPO. Bruising susceptibility. Bruise easily Easy bruisability Easy bruising [ more ]. That is why there have been only a few girls born with hemophilia.
Father with hemophilia; mother a carrier. In some families, there is no known family history of hemophilia. The hemophilia gene seems to appear from nowhere and the family is shocked and confused. There are several reasons this could happen. First, the family may not know about or may have forgotten ancestors with hemophilia. Second, the gene for hemophilia may have been passed down by carrier females without anyone knowing.
For several generations, the women may have had no boy children or by chance had only normal boys. No one would have known about the hemophilia gene. Third, hemophilia may appear in families with no history of it if the normal blood clotting gene suddenly becomes messed up a spontaneous genetic mutation. Normally, genes are exactly copied generation after generation. Sometimes, though, a gene may become faulty. It may give different or wrong directions to the body. This change in the gene is called a mutation.
The effects of the faulty gene may be noticed right away. Or they might not be seen until the gene is passed on to a baby. So the change in the gene may have happened in the parent or in the baby. The change in the gene can be caused by something in the environment. It also seems to happen without any clear cause. Since they are nature's way of bringing about change, not all gene mutations are harmful.
The hemophilia gene can occur in a man or woman this way. The blood clotting gene suddenly becomes faulty. The gene may be passed by female carriers for several generations before hemophilia appears in a boy baby. Probably not. Mutations in blood clotting genes would still happen, making new carriers and new people with hemophilia. It is believed that as many as one-third of the babies born with hemophilia are caused by new gene mutations.
Once the hemophilia gene is present, the chance of passing it on exists. It is possible, however, for hemophilia to disappear from the family tree. This can happen if all family members who have hemophilia or who carry the hemophilia gene give birth to children who by chance do not get the gene. The clotting factor level will be about the same from one generation to the next.
So the daughters of a man with severe hemophilia will all carry the gene for severe. The same goes for men with mild and moderate hemophilia. Their children will all carry the same level.
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