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Changes in the F8
gene are responsible
for hemophilia A
while mutations in
the F9 gene cause
hemophilia B
The F8 and F9 gene provides instructions for
producing the coagulation factor VIII a protein that
helps with blood clotting. 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 coagulation.
Definition of coagulation: to thicken, or cause liquid
to thicken, into a soft semisolid mass
Hemophilia A is caused by a
deficiency of factor VIII and
hemophilia B is caused by a
deficiency in factor IX.
Factor VIII and IX play
essential roles in the blood
Coagulation system.
physical symptoms
•Large bruises
•Bleeding of the mouth and gums, tooth loss
•Blood in the urine
•Digestive problems
•Nosebleeds
•Joint pain and swelling, frequently in the
knees and elbows
•Heavy bleeding, or bleeding that lasts a
long time, from an accident or other injury
•Swelling under the skin and between
muscles, with fever, skin discoloration, and
pain
This condition occurs more commonly in
males. Hemophilia A is the most common type of
the condition. One in five thousand males
worldwide are born with this disorder. Hemophilia
B occurs in approximately 1 in 20,000 newborn
males worldwide. Hemophilia is the most common
X-linked genetic disease.
Hemophilia is linked in the X chromosome. Normal
genotypes are XY, but in an affected human the
genotype would be X and Xh. This is the extra
chromosome that causes the hemophilia. Hemophilia
is passed down from mother to son and is extremely
rare for a woman to have hemophilia. Women must be
a carrier of the disorder for her son to get it.
Females have two X chromosomes and males only
have one. When a boy is born, he takes one X
chromosome from his mother and one Y
chromosome from his father. Therefore, he can
only get hemophilia through his mother. If there is
a mother that is a carrier and has a daughter the
gene could be passed down to her, but it is very
possible she would only be a carrier and have no
symptoms.
Example One:
Mother(Carrier)+Father(NonAffected)=50% chance of their son
acquiring the disorder and 50%
chance of their daughter being a
carrier.
Example Two:
Mother(Not
Affected)+Father(Hemophiliac)=All
sons will be non-affected and all
daughters will be carriers
The two female offspring are heterozygous for
the hemophilia trait and are carriers.
The two male offspring receive an unharmed
X-chromosome and are regular.
There is a male and female
offspring that inherit regular
genes.
One female is heterozygous
for hemophilia and is a
carrier.
One male gets a damaged Xchromosome and will have
hemophilia.
Hemophilia is treated by replacing the missing
clotting factor in the blood. Concentrates of
clotting factor VIII (for hemophilia A) or clotting
factor IX (for hemophilia B) are either dripped or
injected in the vein. This helps to replace the
clotting factors that are either missing or low.
Clotting factors:
•factor concentrates
•cryoprecipitate
•plasma
•whole blood
Nearly all research is being focused on gene
therapy treatment. Hemophilia gene therapy
research is trying to replace the defective
gene with a working functional gene. So far
there have not been any accepted gene
therapy treatments but researchers have
found success of the gene therapy treatment
in mice.
Depending on the severity of a
person hemophilia there quality of life
changes. A person with mild hemophilia
everyday life is not that different than a
normal person's life. Although many
precautions need to be taken to prevent
injury they can do many things that a
normal person can do. Sport is
encouraged so that muscles become
stronger, which then protects the joints
and decreases bleeding. Swimming and
cycling are the two most recommended
sports because they don't put pressure
on the joints.
Sports such as football, basketball,
hockey, and lacrosse are off limits because the
pose to much of a threat for injury. For
moderate and severe types of hemophilia
people have to take more precautions like not
being in crowded of a place. People with severe
hemophilia quality of life is not the same as a
normal person because there is always the
worry and fear that something could happen
and if bleeding did occur there is only a short
time frame for treatments to be made before
the person can bleed out.
Bibliography
1. Http://www.euronet.nl/~jonkr/, Ron Jonk-. "Hemophilia." University of Maryland Medical Center |
Home. Web. 02 Mar. 2011. <http://www.umm.edu/altmed/articles/hemophilia-000076.htm>.
2. Question 679: Blood & Clotting Disorders and Hemophilia | Ask the Geneticist (SM)." Emory University
Department of Human Genetics. Web. 02 Mar. 2011.
<http://genetics.emory.edu/ask/question.php/679/Blood_&_Clotting_Disorders/1/Hemophilia>.
3. "Hemophilia - Genetics Home Reference." Genetics Home Reference - Your Guide to Understanding
Genetic Conditions. Web. 02 Mar. 2011. <http://ghr.nlm.nih.gov/condition/hemophilia>.
4. "Hemophilia A (Factor VIII Deficiency)." Welcome to the National Hemophilia Foundation. Web. 02 Mar.
2011.
<http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=180&contentid=45&rptname=
bleeding>.
5. "Hemophilia - Genetics Home Reference." Genetics Home Reference - Your Guide to Understanding
Genetic Conditions. Web. 02 Mar. 2011. <http://ghr.nlm.nih.gov/condition/hemophilia>.