Genetic Disease Summary: Hemophilia A
Hemophilia is an inherited bleeding disorder that slows down or prevents the blood clotting process. There are two main types of hemophilia: hemophilia A and hemophilia B. Hemophilia A, which is known as classic hemophilia, is caused by a mutation in the F8 gene. People with hemophilia often display excessive bleeding, including bleeding in the stool and urine, though it is usually painless. Joints are also heavily affected, causing swelling and decreased mobility. Rupture of a blood vessel in the brain however, although uncommon, can lead to serious complications. Other symptoms include easy bruising and persistent bleeding from cuts on the lip or tongue. In very severe cases of hemophilia, spontaneous …show more content…
The F8 gene codes for the clotting factor VIII, which is a glycoprotein located in the blood that aids in the coagulation of blood in a blood clot. The gene is around 180,000 nucleotides long, including 26 exons.1 Those exons code for 2,332 amino acids.2 Hemophilia A is inherited through an X-linked recessive inheritance pattern because the F8 gene is located on the X chromosome, specifically Xq28.1 This means that more males than females have Hemophilia A because males only need one X chromosome to be mutated, while females need two X chromosomes to be mutated to get Hemophilia A.3 Clotting factor VIII functions by coagulating in damaged blood vessels to prevent excessive blood loss. If the protein is missing or its function disrupted by a mutation, it cannot participate in this clotting process. Factor VIII is a cofactor for factor IX that, in the presence of calcium ions and phospholipids, forms a complex that activates factor X, which is an enzyme that also helps clot blood by converting fibrinogen to fibrin. Factor VIII is produced in liver cells and endothelial …show more content…
In acquired hemophilia, the body generates antibodies that disable factor VIII. Researchers are still unsure of the exact cause of acquired hemophilia because it occurs spontaneously and can happen after pregnancy or a surgery. There is no apparent reason for the production of these antibodies.6
Model genetic organisms are used to study specific genes or genetic disorders. Current model organisms used to study hemophilia A and the F8 gene are mice and dogs. Dogs are used because some show abnormally excessive bleeding that can be treated with an infusion of canine FVIII. Mice are used because they are small and easy to breed. Even though the abnormal bleeding does not occur naturally in mice, various hemophiliac mouse models have been developed and only require a minute amount of drugs to test.7,8
Tests are performed on individuals suspected to have hemophila to determine whether blood is clotting properly. These tests include a complete blood count which determines the amount of red blood cells, platelets, and white blood cells found in the blood. Although a person with hemophilia shows a normal complete blood count, excessive bleeding can cause the red blood cell count to be very low. Other tests include the prothrombin time test and the activated partial thromboplastin time test, which measures the blood clotting time. If there is a deficiency in any of the
Hemophilia is an inherited bleeding disorder that slows down or prevents the blood clotting process. There are two main types of hemophilia: hemophilia A and hemophilia B. Hemophilia A, which is known as classic hemophilia, is caused by a mutation in the F8 gene. People with hemophilia often display excessive bleeding, including bleeding in the stool and urine, though it is usually painless. Joints are also heavily affected, causing swelling and decreased mobility. Rupture of a blood vessel in the brain however, although uncommon, can lead to serious complications. Other symptoms include easy bruising and persistent bleeding from cuts on the lip or tongue. In very severe cases of hemophilia, spontaneous …show more content…
The F8 gene codes for the clotting factor VIII, which is a glycoprotein located in the blood that aids in the coagulation of blood in a blood clot. The gene is around 180,000 nucleotides long, including 26 exons.1 Those exons code for 2,332 amino acids.2 Hemophilia A is inherited through an X-linked recessive inheritance pattern because the F8 gene is located on the X chromosome, specifically Xq28.1 This means that more males than females have Hemophilia A because males only need one X chromosome to be mutated, while females need two X chromosomes to be mutated to get Hemophilia A.3 Clotting factor VIII functions by coagulating in damaged blood vessels to prevent excessive blood loss. If the protein is missing or its function disrupted by a mutation, it cannot participate in this clotting process. Factor VIII is a cofactor for factor IX that, in the presence of calcium ions and phospholipids, forms a complex that activates factor X, which is an enzyme that also helps clot blood by converting fibrinogen to fibrin. Factor VIII is produced in liver cells and endothelial …show more content…
In acquired hemophilia, the body generates antibodies that disable factor VIII. Researchers are still unsure of the exact cause of acquired hemophilia because it occurs spontaneously and can happen after pregnancy or a surgery. There is no apparent reason for the production of these antibodies.6
Model genetic organisms are used to study specific genes or genetic disorders. Current model organisms used to study hemophilia A and the F8 gene are mice and dogs. Dogs are used because some show abnormally excessive bleeding that can be treated with an infusion of canine FVIII. Mice are used because they are small and easy to breed. Even though the abnormal bleeding does not occur naturally in mice, various hemophiliac mouse models have been developed and only require a minute amount of drugs to test.7,8
Tests are performed on individuals suspected to have hemophila to determine whether blood is clotting properly. These tests include a complete blood count which determines the amount of red blood cells, platelets, and white blood cells found in the blood. Although a person with hemophilia shows a normal complete blood count, excessive bleeding can cause the red blood cell count to be very low. Other tests include the prothrombin time test and the activated partial thromboplastin time test, which measures the blood clotting time. If there is a deficiency in any of the