Tim Poisal Biology-2nd period

Hemophilia is a genetic blood disease, which is characterized by the
inability of blood to clot, or coagulate even from minor injuries. This disease
is caused by an insufficiency of certain blood proteins, called factors, that
participate in blood clotting and often by sudden gene mutation. Therefore,
with the absence of factors, the blood clotting process is prolonged. There are
different types of hemophilia, hemophilia A and hemophilia B for example.
Hemophilia A , the most common form is caused by the lack of factor VIII. In
the second most common form of hemophilia, hemophilia B (also known as Christmas
disease), factor IX is absent.
The condition appears when the person is born. Also, the disease is
hereditary, passed on from parent to child. Because of it\'s genetic makeup,
hemophilia is carried by females however those affected are almost always males.
In one-third of all cases hemophilia thought to be caused by spontaneous gene
mutation with no family history. This is how females are able to be affected
by hemophilia. Inheritance is controlled by a recessive sex-linked factor
carried by the mother on the X chromosome. There is a fifty percent chance that
the sons of a female carrier will have hemophilia. There also is a fifty
percent chance that the daughters of a female carrier will be carriers of
hemophilia. In addition, all daughters of men with hemophilia are carriers, but
his sons are unaffected. Men cannot transmit hemophilia, and female carriers
are free of the disease.
Hemophilia is the most common hereditary blood disorder. Currently,
approximately one in every 10,000 people in all parts of the world suffers from
hemophilia. This blood related disease affects about 20,000 people in the
United States. It affects males almost exclusively and knows no geographical or
ethnic boundaries. Before medical advancement, those affected by hemophilia
were not likely to live to see their adulthood. With proper treatment they can
expect to lead full, normal lives. However, in some countries where treatment
is not available or less than optimal, people have continued to die at young

Category: Science