Biology 30 - Hemophillia

Hemophilia

By Chelsea Stevenson

Biology 30

Mr Friesen

May 18, 2005

Hemophilia is a hereditary bleeding disorder. (1, 36)(2, 759)(3, 529)(5, ____) (6) (7) (8) (10) (12) (13) (14) Hemophilia is a disease where the blood does not clot normally. (1, 36)(3, 529)(2, 759)(5,____)(6)(10)(13) "Hemo" means blood and "philla" means a tendency towards.(6)(7) In most people when they get a cut the platelets plug the hole and release chemicals which attract proteins and activate proteins found in the blood that are known as clotting factors.(6) The proteins mix with the platelets and create fibres; the fibres then make the clot stronger and stop the bleeding.(6) Hemophilia is a deficiency in one of the 12 blood clotting factors. (2, 759)(3, 529)(5, )(6)(8)(12)When blood doesn't clot as fast as it is supposed to heavy blood loss can occur as well as body organs and tissues can be damaged and can result in permanent injury or death.(13) There are two different types of Hemophilia this was discovered in 1950s.(6)(10)(13)(14) The first type is Hemophilia A which is a deficiency in Clotting factor VIII and accounts for about 80% of all cases. (6)(10)(13) (14) The second type is Hemophilia B (Christmas disease) which is a deficiency in Clotting factor IX it occurs in 1 in 34,500 males. (6)(10)(13)(14) Also there are three levels of severity of hemophilia. (6)(13)If a person produces 1% of a normal level of clotting factor or less then they have severe Hemophilia. (6)(13) If they produce 2% to 5% of the normal level they have moderate Hemophilia, someone who produces 6% to 50% of the normal level they have mild hemophilia. (6)(13) If you have mild hemophilia u might bleed excessively only once in a while, while someone with severe hemophilia is more prone to bleeding excessively often. (6)(14) Most people with hemophilia discover the condition at a very young age. (6) But, sometimes a person with very mild hemophilia will not discover it until they have a minor surgery; it's discovered in the blood tests that the doctors perform before the surgery. (6)

Hemophilia is caused by a defective gene on the X chromosome. (4)(5,____)(6)(7)(8)(13)The Y chromosome has no genes for clotting factors so it is not affected. A boy who has the defective X chromosome will be a haemophiliac. (5, ____) (6)(13) (14) Where as a girl with the defective X chromosome will be a carrier of hemophilia. It is extremely rare for a girl to inherit hemophilia on both X chromosomes. (6) (5, ____) Therefore hemophiliacs are almost exclusively male. (2, 759) (3, 529) (5, ____) (6) (7) (8) (10) (14)The defective X chromosome is inherited from the mother and passed on to the male children almost exclusively and the female children have a 50% chance of being a carrier of the condition(5, ____) (6) (7). In order for a female to have hemophilia she would have to receive the defective X chromosome from her father and mother. (5, ____) (6) (7). A female hemophiliac is not impossible it is just very unlikely. About one in ten thousand males are born with hemophilia. (8) (3, 529) (10) Some cases of hemophilia occur with a mutation of the gene, this happens in about one third of new cases. (3, 529) (14)

In most cases the first bleeding episode occurs before 18 months of age after some sort of mild injury. (2, 759) Symptoms of hemophilia in mild cases of the condition don't show until the person has blood tests and hemophilia is discovered. (6) Some of the symptoms include: prolonged but not excessive bleeding from minor cuts and abrasions, spontaneous bleeding, pain and swelling that results from bleeding into the joints and muscles, bruising, blood in the urine or stool and prolonged bleeding after circumcision. (6) (10) (2, 759)The severity and frequency of the bleeding episodes can vary from patient to patient it also depends on the type of hemophilia. (10) Injection into a muscle can cause bleeding that result in a large bruise called a hematoma. (2, 759) Bleeding into the joint is a huge concern for hemophiliacs because they can lead to crippling deformities. (2, 759) (12) (14) (5, ____)(1, 36) (8) (6)

Hemophilia is not curable, (1, 36) but in the more severe cases of hemophilia there are effective treatment options available. Unfortunately only 25% of people receive adequate treatment. (14) Without treatment hemophiliacs can experience crippling pain, severe joint damage and disability (14) Clotting factor replacement therapy which uses plasma derived clotting factor concentrates are often used as treatment. (9) (13) (14) (5, ____)(2, 759) (6)They are taken from the plasma that is pooled from thousands of blood donors. (9)The plasma has to be pooled and collected and processed to separate the clotting factors. (9) The blood donors have to be very carefully screened so that blood borne diseases (2, 759) (5, ____) (9) and viruses such as HIV and AIDS are not transmitted to the patients. In the 1980's 60% of hemophiliacs that were treated became infected with HIV. (2, 759) (5, ____) But fortunately transmission has been virtually eliminated because of use of screened and processed blood. (2, 759) The clotting factor concentrates are very expensive but they are also very effective. (14). Sometimes hemophiliacs can develop antibodies to transfused factors VIII and IX which makes transfusions ineffective. (12) When antibodies are detected the dosage of the concentrates may be increased, different clotting factors may be used or drugs to reduce antibodies may be used. (12) Hemophiliacs often work with a group of hematologists (doctors that specialize in bleeding disorders), nurses and social workers. They teach the hemophiliac