Hemophilia is the name of a group of hereditary blood disorders characterized by deficiencies in the blood’s capability to type clots. Although hemophilia varies in severity from individual to person, all patients with the disease bruise effortlessly and bleed for abnormally long periods of time when cut. There are two main types of hemophilia: hemophilia A, occasionally called classic hemophilia, which accounts for about 80 % of cases; and hemophilia B, known as Christmas illness, which accounts for the remaining 20 %.
Both types are triggered by gene mutations, hemophilia A by a mutation of the F8 gene and hemophilia B by a mutation of the F9 gene. Both genes are situated on the X chromosome, which indicates that females (who've two X chromosomes) can transmit the mutations that trigger hemophilia, but males (who have only one X chromosome) get the disease.
There's a very uncommon form of hemophilia known as acquired hemophilia, which means that the illness isn't genetic but develops later in life. It results from an autoimmune reaction in which the body attacks its personal production of coagulation element VIII, one of the blood factors required for normal clotting.
Hemophilia is a disease that has been known for centuries, even though ancient medical doctors could do little to treat it. It was not till 1803 that John Otto, a physician in Philadelphia, noted that the illness ran in families but that only males suffered from it. Hemophilia became known as the royal illness in the later nineteenth century, when several descendants of Queen Victoria (1819-1901) including the queen’s youngest son, Leopold died young from brain hemorrhages.
Two of Victoria’s daughters were carriers of the defective F8 gene and passed on the illness to the royal houses of Spain, Russia, and Germany. It was not until the twentieth century that medical doctors had been in a position to understand the trigger of hemophilia. At first they believed that it resulted from unusually fragile blood vessels. In the 1920s, medical doctors believed that defective platelets, cells in the blood involved in clot formation, were to blame. By 1937, nevertheless, it was discovered that substances dissolved in blood plasma, the liquid part of blood, were a necessary part of the normal clotting procedure.
These proteins in the plasma had been called coagulation factors. By 1944, a physician in Argentina discovered that you will find two distinct types of hemophilia, each triggered by a deficiency of a specific coagulation factor. It was not till 1965, nevertheless, that an additional physician found a way to separate the protein factors from the liquid part of blood plasma by a freeze-drying process.
This technique made it possible for people with hemophilia to be treated without frequent high-volume blood transfusions, previously the only technique of treatment. To understand the significance of these advances and discoveries, it helps to understand how blood clots are generally formed. When a blood vessel is cut, it contracts to slow down the bleeding. Platelets in the blood go to the break or cut and type a clump or plug to patch the hole. The coagulation factors in the blood interact with the platelets and other chemicals in the blood to form a network or web that holds the clot in location. This complicated series of chemical reactions is known as the coagulation cascade.
People with hemophilia, nevertheless, have low quantities of coagulation factors. The severity of hemophilia depends on the degree of the coagulation factors. A person with mild hemophilia has in between 5 and 40 percent of regular coagulation factor activity; a person with moderate hemophilia has in between 1 and 5 percent; an individual with severe hemophilia has less than 1 percent of regular coagulation factor activity.
Hemophilia A will be the more common form of the disorder, occurring in about one in every 4,000 male infants about the world. Hemophilia B affects about one in every 20,000 newborn boys. Girls who carry a defective F8 or F9 gene usually do not suffer from the disease; however, about 10 percent of girls with one abnormal copy of either defective gene will experience heavy menstrual periods and other mild problems with bleeding. As far as is recognized, both hemophilia A and hemophilia B are equally typical in all racial and ethnic groups around the world. About 60 percent of persons diagnosed with hemophilia A and 44 percent of persons with hemophilia B have severe disease.
Both hemophilia A and B are caused by genetic mutations that have an effect on the blood’s capability to clot usually. With out sufficient element VIII (in the case of hemophilia A) or element IX (in the case of hemophilia B), the platelets that move towards the cut or break in a blood vessel aren't held securely within a network of protein fibers. They cannot form a clot powerful enough to effectively stop the bleeding, which continues for a longer period of time than in regular people. The symptoms of hemophilia may include:
The diagnosis of hemophilia depends in part on its severity. Male babies with severe hemophilia are frequently diagnosed shortly after birth, particularly if they are circumcised. In some cases the disorder is diagnosed when the toddler begins to walk, bruises effortlessly, or starts having nosebleeds. Patients with milder hemophilia may not be diagnosed until they're older and have prolonged bleeding following dental work or minor surgery.
The most common test utilized to diagnose hemophilia is a blood test. A sample of the patient’s blood is analyzed for the quantity of clotting element activity that is present. Genetic testing may also be used to diagnose individuals who've only mild signs and symptoms of hemophilia A or B, as well as identify ladies who're carriers of hemophilia gene mutations before they become pregnant.
There is no cure for hemophilia. Treatment is directed at preventing severe bleeding episodes and managing symptoms once they do occur. Sufferers with mild hemophilia A might be treated with injections of a hormone called desmopressin or DDAVP, which stimulates the patient’s body to release more of its own clotting factor. Sufferers with hemophilia B or moderate to severe hemophilia A are treated with clotting factors derived from donated human blood or from genetically engineered blood products called recombinant clotting factors.
Patients with hemophilia could be taught to inject themselves with desmopressin or clotting factors at home two or 3 occasions a week as a type of prophylaxis, or preventive measure. Sufferers with severe hemophilia whose joints have been damaged by bleeding usually need physical therapy to restore range of motion and strength in the damaged joints. They may ultimately need to have the joints replaced with artificial joints in adult life.
The life expectancy and quality of life for males with hemophilia have increased significantly since the 1950s. Before 1960, the average life expectancy of a boy with hemophilia was 11 years. Early death was often preceded by severe pain from bleeding into the joints. As of the early 2000s, life expectancy has increased to fifty-five to sixty years. Older males with severe hemophilia who were treated in the late 1970s or early 1980s are still at risk of death from AIDS; 90 percent of these sufferers are HIVpositive. About 8 percent of patients with hemophilia ultimately die from bleeding into the brain. About 25 % of children in between six and eighteen years of age with severe hemophilia have below-normal academic skills and an increased risk of emotional and behavioral problems.
Hemophilia can be prevented in part by genetic testing of potential parents. Even though males with hemophilia cannot pass the illness on to sons, they can father daughters who will carry the illness towards the subsequent generation. Hemophilia can't be totally eliminated by family planning, however, as 34 % of all hemophilia A cases and 20 percent of all hemophilia B cases are triggered by spontaneous mutations in each generation.
Hemophilia will always be rare, but it is unlikely to ever be completely eliminated for two factors. One is the role of spontaneous mutations in producing defective F8 and F9 genes in each new generation. The other cause is that most men with hemophilia now live lengthy enough to father children and pass on the defective genes. Simply because of this change in life expectancy, researchers are presently concentrating on gene therapy as a feasible remedy for hemophilia. In gene therapy, a normal gene to replace the defective gene is inserted into the patient’s genetic material by using a virus as a carrier. Research on gene therapy for hemophilia A is being carried out as of 2008.
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