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What is a Bleeding Disorder?
A bleeding disorder exists when it is hard for a person to stop
bleeding. When a person bleeds, the blood clots, stopping the bleeding.
The clotting process, also called coagulation, changes blood from
a liquid to a solid state. It takes both blood cells (called platelets)
and proteins (called clotting factors) for blood to clot properly.
When a person has a bleeding disorder, the blood platelets are not
working like they should, or there are not enough platelets or clotting
factors in the blood. This causes a person to bleed for longer periods
of time than normal.
Normal blood coagulation is a complex process involving as many
as 20 different plasma proteins, which are known as blood clotting
or coagulation factors. Normally, these factors interact with other
chemicals to form a substance called fibrin that stops bleeding.
When certain coagulation factors are deficient or missing, the process
is impaired. Bleeding problems can range from mild to severe.
Some bleeding disorders are present at birth and are caused by
rare inherited disorders. Others are developed during certain illnesses
(such as Vitamin K deficiency or severe liver disease), or treatments
(such as use of anticoagulant drugs or prolonged use of antibiotics).
These disorders can be either inherited or acquired. The acquired
forms often arise from the side effects of certain drugs. These
disorders can be controlled, so a person can have a healthy and
full life.
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What is Hemophilia?
Hemophilia is an inherited bleeding disorder, predominantly affecting
males. There are two major forms of the disease - hemophilia A (factor
VIII deficiency) and hemophilia B (factor IX deficiency). People
with no family history can also develop hemophilia A. NHF says this
accounts for a third of all cases. It usually happens after a new
or spontaneous gene mutation.
Hemophilia may result from gene mutations: point mutations involving
a single nucleotide, deletions of all or parts of the gene, and
mutations affecting gene regulation. About 50% of cases of severe
hemophilia A result from a major inversion
of a section of the tip of the long arm of the X chromosome. Because
factor VIII and factor IX genes are located on the X chromosome,
hemophilia affects males almost exclusively. Daughters of hemophiliacs
will be obligatory carriers, but sons will be normal. Each son of
a carrier has a 50% chance of being a hemophiliac, and each daughter
has a 50% chance of being a carrier. Rarely, random inactivation
of one of the two X chromosomes in early embryonic life will result
in a carrier's having a low enough factor VIII or IX level to experience
abnormal bleeding.
Click
here, for a diagrammatic representation of the inheritance of
Hemophilia. Hemophilia is also known as the 'Royal
Disease' as it was found in the children of Great Britain's
Queen Victoria.
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What is von Willebrand Disease?
von Willebrand Disease is a hereditary deficiency of von Willebrand
factor in blood, occurring in 1% to 2% of the population. The factor
is a protein that affects platelet function. von Willebrand disease
was first recognized in 1925 by Erik von Willebrand, a Finnish physician,
who described a new type of bleeding disorder in inhabitants of
the Aland Islands.
According to NHF there are many variations of von Willebrand disease
including:
- Type I: Most common and mildest form of the disease. The von
Willebrand factor levels are lower than normal and factor VIII
levels may also be low.
- Type II: The von Willebrand factor is abnormal.
- Type III: Severe von Willebrand disease. A total absence of
von Willebrand factor and low levels of factor VIII.
- Pseudo von Willebrand disease: Platelets are defective rather
than the von Willebrand factor.
Symptoms of von Willebrand disease include frequent or prolonged
nosebleeds, easy bruising, bleeding gums, bleeding following dental
work, and heavy menstrual periods
Click
here, to learn how von Willebrand Disease is inherited.
Links to other bleeding disorders information:
http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=2&contentid=5
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