What is hemophilia?:

Hemophilia is a genetic disorder of the workings of blood clotting. People with this disorder have hemophilia A, hemophilia B, or hemophilia C. Depending on the severity of the disorder for a person, excessive bleeding occurs after harming events, or occur spontaneously with no known initiating event.

How is it inherited?:

Hemophilia is a sex-linked trait. It occurs when there is a deficiency with the VIII and IX factors - critical blood clotting genes - carried on the X chromosome. However, there are a few cases where there was simply a mutation during the formation of the X chromosome(s). Hemophilia C is inherited from parent to child as well, but is not a deficiency with the X chromosome. It is instead caused when there is a problem with the FXI factor (produced in the liver) and not enough is produced. This means that it can affect both males and females just as equally.

Below is a pedigree chart to show the inheritance of hemophilia within a Russian imperial family.
(Red is the hemophilia trait. A circle stands for a female, and a square stands for a male individual. In a female, when the shape is only half-way colored, they only carry one of the hemophilia genes, and therfore are only carriers of the gene. Men with the gene will always be completely colored because men only have one X chromosome that can carry the gene.)
external image chart4.gif

The punnett square below is an example of how the trait is inherited when only the mother carries the gene.
How hemophilia is carried.
How hemophilia is carried.


The punnett square below is an example of how hemophilia is inherited when the gene is carried only by the father.
How hemophilia is carried.
How hemophilia is carried.


Signs and Symptoms:

The more common and obvious symptoms for hemophilia are excessive bleeding from small cuts and scrapes, or very easy bruising. These are usually recognized after an accident, a dental exam, a lot of bleeding after losing a tooth, or during a routine circumcision that causes heavy bleeding. In severe cases, the first excessive bleeding incident occurs prior to eighteen months of age. The less noticeable symptoms are bleeding on the joints, muscles, and and in the brain. These last three are much more serious symptoms and are usually more common with those who have hemophilia B. When bleeding on the joints occurs, at first it is almost unnoticeable. But after a while, the joint swells, is warm to the touch, and is very painful for the one experiencing it. It can cause scarring in within the joints and cause permenent deformities. Also, it can cause arthritis to develop and mouth injuries can result in compression of the airway. As a child becomes more active, the muscles may begin to suffer from bleeding and can put a lot of pressure on the nerves in the area of bleeding, result in numbness and decrease the ability to use the injured limb. Those with hemophilia C do not typically experience as much internal bleeding as those with hemophilia A or B. However, after surgery in the mouth or nasal areas, after childbirth, or any serious accidents can have quite serious episodes of bleeding.

Treatments:

Treatments for this genetic disorder do exist. For hemphilia A, doctors can inject hormone desmopression (DDAVP). Individuals that possess hemophilia B can get blood fusions with normal clotting blood, and thay may need to do this multiple times. In the case of hemophilia C, patients can get plasma infusions in the United States. All patients are greatly advised to advoid injury and also medication or drugs that may result in bleeding. People who require dental work or surgey may need to be pre-treated with an infusion of factor VIII and IX to replace their missing factors.

Interesting Facts:

Did you know:
  • Males are more likely to get hemophilia because they only have one X chromosome. Females have two X chromosomes, so they usually inherit another "normal" X chromosome to cover up the flawed one;
  • Hemophilia is some times referred to as the "Royal Disease" Queen Victoria's line had hemophilia, which eventually spread out to the other royal families, including Russia, Germany, and France;
  • Some earlier treatments of hemophilia included purified, dried plasma from blood, which actually spread blood borne diseases such as Hepatitis C and HIV throughout the hemophiliac community

Pictures:

Noticeable and severe lumps, and excessive bleeding.

hemophilia-types1-290x300.jpg
hemophilia.jpg

Very easily bruised.
hemophilia
hemophilia




Works Cited:

"Beginner Guide to Genes, Mutations and Hybrids." Feisty Feathers. N.p., n.d. Web. 1 Mar. 2012.
<http://feistyhome.phpwebhosting.com/genes.htm.>
"District 202 - Plainfield East High School." Plainfield Community Consolidated School District 202. N.p., n.d. Web. 1 Mar. 2012.
< http://www.psd202.org/PEHS/departments/science/tmurphy/sixth_hour_web/Hemophilia/symptons_and_characteristics.html>

"Hemophilia ." Genetics Home Reference - Your guide to understanding genetic conditions. N.p., n.d. Web. 24 Feb. 2012.
<http://ghr.nlm.nih.gov/condition/hemophilia>
"Hemophilia C « IHTC." IHTC. N.p., n.d. Web. 2 Mar. 2012.
<http://www.ihtc.org/medical-professionals/blood-disorders/bleeding-disorders/hemophilia-c/>

"Hemophilia signs and symptoms, bleeding, bruising." NIH Heart, Lung and Blood Institute. N.p., n.d. Web. 28 Feb. 2012. < http://www.nhlbi.nih.gov/health//dci/Diseases/hemophilia/hemophilia_signs.html// >

"Hemophilia: The Royal Disease - Case Study Collection - National Center for Case Study Teaching in Science." Redirect to NCCSTS. N.p., n.d. Web. 27 Feb. 2012. <http://www.sciencecases.org/hemo/hemo.asp>.

"Hemophilia: Treatments and drugs - MayoClinic.com." Mayo Clinic. N.p., n.d. Web. 28 Feb. 2012.
<http://www.mayoclinic.com/health/hemophilia/DS00218/DSECTION=treatments-and-drugs>

Narins, Brigham. "Opposing Viewpoints In Context." The Gale encyclopedia of Genetic Disorders. 2nd ed. Detroit: Thomson Gale, 2005. 592-596. Print.