Hemophilia B Lack Factor IX example essay topic

Hemophilia is the oldest known hereditary bleeding disorder. There are two types of hemophilia, A and B (Christmas Disease). Low levels or complete absence of a blood protein essential for clotting causes both. Patients with hemophilia A lack the blood clotting protein, factor V, and those with hemophilia B lack factor IX. A person with severe hemophilia has less than 1% of the normal amount of a clotting factor - either Factor V (8) or Factor IX (9). People without hemophilia have between 50-150% of the normal level of factor V or IX.

There are about 20,000 hemophilia patients in the United States. Each year, about 400 babies are born with this disorder. Approximately 85% have hemophilia A and the remainder has hemophilia B. The severity of hemophilia is related to the amount of the clotting factor in the blood. About 70% of hemophilia patients have less than one percent of the normal amount and, thus, have severe hemophilia.

A small increase in the blood level of the clotting factor, up to five percent of normal, results in mild hemophilia with rare bleeding except after injuries or surgery. This is not a problem when a person with hemophilia has a simple cut or scrape. He doesn't bleed any faster than the average person. He can hold pressure on the cut and platelets in the blood will stop the bleeding.

The problem for people with hemophilia is bleeding inside the body, especially bleeding into joints like the knees, elbows, and ankles. When bleeding happens inside the joint, it becomes very swollen and painful. Repeated bleeding into a joint can cause a type of crippling arthritis. Bleeding inside other parts of the body, such as the brain, throat, and abdomen can be life-threatening.

A person with mild hemophilia may only have problems with bleeding when he has surgery, major dental work, or a severe injury. A person with moderate hemophilia will have those problems plus bleeding problems with more minor injuries such as a hard bump to the knee. A person with severe hemophilia can have what are called spontaneous bleeds - bleeding that starts inside the body for no known reason. Hemophilia is classified as mild, moderate or severe, depending on the amount of clotting factor a person has in his body. Severe hemophilia is actually the most common form.

People with hemophilia are born with the disorder and have it all of their lives. You can't catch hemophilia from someone else. Hemophilia is a genetic disorder - it is passed down generation to generation through a family's genes. Because the genetic defect occurs on the X chromosome, women are carriers of hemophilia but rarely have the disorder. Hemophilia occurs almost exclusively in men. In about one-third of the babies born with hemophilia, the disorder is believed to be due to a spontaneous mutation of the gene.

There is no family history of hemophilia. To determine a sex linkage inheritance of a defective trait, look at a family pedigree to notice the similarities and patterns of the trait throughout the family pedigree for example the pedigree below: Normal Female Normal Male Normal, but known carrier female Affected Male The first generations are skipped, although Nicolas (1904-18) was a hemophiliac, neither his parents nor grandparents were. This pattern occurs in several other places of the pedigree, and indicates a recessive mode of inheritance. From the biochemical nature of the defect, scientists have determined that hemophilia is a recessive trait. All the affected individuals are sons, strongly suggesting that the defect is a sex linkage trait. Since males are for the X chromosome, more males than females should have the phenotype of a sex-linked recessive trait because males do not have a second X chromosome that might carry the normal allele.

The first prediction that we can make from this is that all males get their X chromosomes from their mothers; affected males should be the offspring of carrier, heterozygous, females. A female is automatically a carrier if her father had the disease. She has a 50% chance of being a carrier if her brother, but not her father, has the disease. In that case her mother was the carrier. There are several different inherited forms of hemophilia are known, each deficient on one of the steps in the steps in the pathway that forms fibrinogen, the blood clot protein. Two of these forms "classic" hemophilia A and hemophilia B, also called Christmas disease, are sex linked.

Other hemophilia are. Hemophilia is a very rare disorder. Very few people have it. There are about 17,000 people in the United States with hemophilia. One out of every 5,000 boys born has hemophilia. This makes it about as rare as triplets (three babies in one birth).

There are several signs to recognize hemophilia, those signs are big bruises; bleeding into muscles and joints, especially the knees, elbows and ankles; sudden bleeding inside the body for no clear reason; prolonged bleeding after a cut, tooth removal, surgery or an accident. THE HISTORY OF HEMOPHILIA Effective treatment has only become available in recent decades, hemophilia was known to the ancient world. The earliest written references to what appears to be haemophilia are encountered in Jewish texts of the second century AD. Rabbinical rulings exempted male boys from circumcision if two previous brothers had died of bleeding after the procedure.

The Jewish physician Moses Maimonides (1135-1204) applied this ruling to the sons of a woman who had married twice, thus apparently appreciating the hereditary nature of the condition. The Arabic physician Albucasis (1013-1106) also described a family where males died after trivial injury. First descriptions The first modern description of haemophilia is attributed to Dr. John Conrad Otto, a physician in Philadelphia, who in 1803 published a treatise entitled 'An account of an haemorrhagic disposition existing in certain families. ' He clearly appreciated the three cardinal features of haemophilia: an inherited tendency of males to bleed. Otto traced back the pedigree of the family he studied to a woman who had settled near Plymouth, New Hampshire, in about 1720. However, the first use of the word 'haemophilia' appears in an account of the condition written in 1828 by Hopf f (' "Uber die haemophilia oder die Anlage zu tod lichen Blutungen'), a pupil of Sch " olein at the University of Zurich.

Haemophilia B was only distinguished from the more common type in 1952, and is often referred to as 'Christmas disease' after the surname of the first child reported with this condition. Haemophilia is sometimes referred to as "the royal disease" because several members of noble families in Europe were affected by it. Queen Victoria had no ancestors with the condition but soon after the birth of her eighth child, Leopold, in 1853, it became evident that he had haemophilia. Queen Victoria was thus an example of how the condition can arise as a spontaneous mutation. Leopold died at the age of 31 from an intra cerebral haemorrhage after a fall. Two of Queen Victoria's own daughters, Alice and Beatrice, were also carriers of haemophilia.

The condition was transmitted through them to several royal families in Europe, including Spain and Russia. Perhaps the most famous affected individual was the son of Tsar Nicholas II of Russia, Tsarevich Alexis, who was born in 1904. There has been speculation that the illness led to severe strain within the royal family, and enabled Rasputin to gain influence over the family, ultimately leading to the downfall of this once powerful dynasty. Early treatments Many reputable scientists claimed early success in treating with unusual substances.

A report in The Lancet in 1936 extolled the virtues of a bromide extract of egg white. As recently as 1966, a report in the esteemed scientific journal Nature claimed that peanut flour was also effective for the treatment of haemophilia. The first hint of success came with the report from R.G. Macfarlane in 1934 that snake venous could accelerate the clotting of haemophilic blood, and he reported success in controlling superficial bleeds in people with haemophilia after topical application. Blood transfusion However, the major advances came from developments in the field of blood transfusion. A report from a surgeon, Samuel Lane, in The Lancet in 1840 described the control of post-operative bleeding with fresh blood in a boy with severe haemophilia. However, a lack of understanding of blood groups and basic transfusion methods hindered further development at the time.

The identification of factor V and the development of specific assays then permitted the subsequent development of therapeutic materials. Plasma concentrates In the early 1950's, plasma from animals was used for treatment. While often effective, allergic reactions to these porcine and bovine materials were frequent and often severe. The work of Dr. Edwin Cohn in developing fractionation of plasma with variation of temperature and concentrations of saline and alcohol led to the development of fairly crude plasma concentrates of human factor V in a number of centres ('AHG' or 'anti haemophilic globulin'). A truly major advance was the discovery by Dr. Judith Pool in 1965 that slow thawing of plasma to around 4 oC led to the appearance of a brown sediment which was rich in factor V, which she called. Within a decade, lyophilized coagulation factor concentrates made an appearance.

These offered considerable advantages: they could be stored in a domestic refrigerator at 4 oC, and permitted the administration of a large and assayed quantity of coagulation factor rapidly and in a small volume. The availability of such products facilitated home treatment, allowing patients for the first time to treat themselves at home, work, school, or even whilst on holiday abroad -- freeing them from the physical and psychological shackles of haemophilia. However, we now recognize that this introduced the potential for the transmission of viruses. The impact of HIV was particularly devastating, with large numbers of patients around the world being infected in the period 1979-1985. The hepatitis C virus (HCV) was first identified in 1989, and it soon became clear that an even higher proportion of people with haemophilia had been exposed to this virus which results in chronic liver disease. Fortunately, the introduction of physical treatments of concentrates such as exposure to heat or the addition of a solvent-detergent mixture has effectively eliminated the risk of the transmission of these viruses.

Another landmark was the recognition by Prof. Pier Mannucci in 1977 that (DDAVP) could boost levels of both factor V and von Willebrand factor, and this remains a useful option in mild forms of these conditions. Recombinant products and gene therapy The structure of the factor V gene was characterized and cloned in 1984. This led to the availability of recombinant (genetically engineered) factor V a decade later. The availability of safe products has stimulated the growth of prophylactic treatment, although it must be emphasized that the concept is certainly not new and was developed by Prof. Inga Marie Nilsson in Sweden in the 1950's. The rate of progress continues apace, and gene therapy is a realistic goal. However, we do not forget that many people with haemophilia around the world still receive absolutely no treatment.

Perhaps the current position can best be expressed in words paraphrased from Sir Winston Churchill: this is not the end of our struggle to conquer haemophilia, and not even the beginning of the end. However, we can at least say that this is the end of the beginning of our campaign. Hemophilia-Timeline Although it is only in the last 50 years or so that hemophilia and its treatment has been really understood, the disorder has a much longer history. Here are some of the major milestones in the history of hemophilia and its treatment. While this timeline focuses mostly on the breakthroughs and successes, it should be noted that the evolution of medical care of hemophilia was not a straightforward progression.

There were many bumps and turns along the way to understanding this disorder and developing effective treatment. circa 100 First written reference to a bleeding disorder, by Rabbi Judah the Patriarch, exempting male infants from circumcision if elder brothers had died as a result of this procedure. circa 1100 Albucasis, an Arabic physician, documents in a medical handbook that uncontrollable bleeding disease in males is best treated with cautery. This is the first written reference to hemophilia treatment. Moses Maimonides, a physician and talmudist who lived in Egypt, extends Rabbi Judah's ruling exempting male infants from circumcision to the sons of women who have married twice, suggesting an awareness of the inheritance of hemophilia. 1793 Cons bruch of Germany publishes the first modern description of hemophilia.

1803 American physician John Conrad Otto publishes an article on hemophilia that stimulates research and publication by others. 1823 The term hemophilia is coined by Schonlein of Germany for all bleeding problems; the term is applied to just inherited disorders after 1828, when it is first published in the title of a dissertation by a student of Schonlein's. 1840 The first successful blood transfusion for postoperative bleeding in a boy with hemophilia is performed by Samuel Lane, an English physician. 1853 Queen Victoria of England's son, Leopold, is born with hemophilia. Two of Queen Victoria's daughters are carriers and spread what becomes known as "the royal disease" throughout the ruling families of Europe and Russia.

1904 Alexis, son of Tsar Nicholas II of Russia, is born with severe hemophilia. 1934 R.G. MacFarlane, a British pathologist, learns that Russell's viper venom helps hemophilic blood to clot. Commercial production of "Sty pen" for hemophilia treatment begins soon afterwards; it is still produced today. 1936 Plasma first used to treat hemophilia. 1937 American researchers A.J. Patek and F.H.L. Taylor find that intravenous administration of plasma precipitates shortens blood clotting time. Taylor later calls the precipitates anti hemophilic globulin.

1939 American pathologist Kenneth Brinkhous shows that people with hemophilia have a deficiency in the plasma factor he later calls anti hemophilic factor, now called factor V. 1944 Edwin Cohn, an American biochemist, develops fractionation, a process of separating plasma into its different component parts. 1946 Cohn and his colleagues demonstrate that one of the blood fractions (Cohn Fraction I) indicated anti hemophilic activity. American physician Armand Quick came to the same conclusion using different methods in the same year. 1952 Researchers in San Francisco, New York, and Oxford describe a new type of hemophilia, arising from a defect in what is now known as factor IX. Rosemary Biggs from Oxford U.K. calls it Christmas disease, named for the first patient, Stephen Christmas. 1955 American pathologists Robert Lang dell, Robert Wagner, and Kenneth Brinkhous develop intravenous infusions of factor V, the first effective therapy for hemophilia.

1957-8 Human preparations of factor V are developed in Britain, France, and Sweden. 1958 Inga Marie Nilsson, a Swedish physician, begins prophylaxis in treatment of boys with severe hemophilia A. Regular prophylactic treatment does not begin until the early 1970's. 1961 First experiments with concentrates of factor V. 1964 American researcher Judith Pool publishes a paper reporting that freezing and thawing plasma slowly produces a by-product which is rich in factor V. Cryo precipitate revolutionizes the treatment of hemophilia. Mid-1960's Total hip replacement and later knee replacement surgery is developed in the U.K. 1968 First factor V concentrate becomes commercially available.

1977 Italian Pier Mannucci recognizes that (DDAVP) can boost the level of both factor V and von Willebrand factor in blood. 1980 Bovine spongiform encephalopathy (BSE) epidemic begins in cattle herds in the U.K. 1982 First reported cases of AIDS in people with hemophilia. 1984 First experiments with heat-treated product conducted by the U.S. Centers for Disease Control and Prevention, which showed that heat destroyed HIV. Factor V gene is characterized and cloned. 1985 Viral-inactivated factor concentrates become available. ELISA and Western Blot Test are developed to test antibodies for HIV.

1989 Hepatitis C virus, previously called non-A, non-B, is identified. 1991 Testing for hepatitis C is introduced. 1992 First recombinant factor V products become available. 1995 First case of variant Creutzfeldt-Jakob disease, the human form of Mad Cow disease, is identified in the U.K. 1997 First recombinant factor IX products become available. 1998 Gene therapy trials on humans begin.

Effective treatment for hemophilia is available, but as yet there is no cure. Bleeding can be treated with an injection of clotting factor that is made from blood or biotechnological ingredients called recombinant's. Bleeding stops when enough clotting factor reaches the affected area.

Bibliography

I. Principles Of Genetics 7th Edition, Robert H. Tamarin. 2002 II. World Federation of Hemophilia. web Hemophilia of Georgia. web Hemophilia Village. Hemophilia village. com.