Down Syndrome - Research Paper Example

? Down syndrome Down syndrome Introduction Chromosomes are the basic unit of cells which contain the organized form of DNA in a coiled form. These chromosomes undergo different type of abnormalities during the genesis of human beings. Chromosomes are units which are transferred from parent to offspring through different processes. In certain cases this transfer is not successful and this leads to chromosomal abnormalities. These abnormalities occur due to different reasons such as radiations or chemicals. Primary abnormalities in the chromosomal structure are related to four classes which are deletions, inversions, translocations and ring chromosome. In this assignment the particular emphasis would be on translocation as it occurs in Downs’ Syndrome. Downs’ Syndrome is also known as trisomy 21 in which the process of translocation occurs on the chromosome number 21. This essay would further revolve around Downs’ Syndrome putting forward each and every aspect that is important in understanding the syndrome. Translocation In order to understand the basics of Down syndrome one has to know enough about the structural abnormality of translocation. Translocation is a process in which the whole segment of a chromosome is exchanged by another chromosome. In other words a part of chromosome is exchanged with another part of another chromosome. There are two types of translocations known as reciprocal translocations and Robertosonian translocations. Reciprocal translocation takes place when segments are exchanged between nonhomologous pairs of chromosomes. Reciprocal translocation usually does not cause any disease or symptom but it may cause leukemia. However in some cases this type of translocation leads to abnormal fertilization and hence abnormal birth. Robertosonian translocations are the ones which are more lethal and occur between two acrocentric chromosomes. The acrocentric chromosomes break near the centromere or the middle part of the chromosome and then join together in such a way that the p arm of the chromosome is lost. This type of translocation occurs in many different types of syndromes and can cause a profound effect on the individual. Trisomy 21 or Down syndrome is a cause of Robertosonian translocation and has a profound effect on the individual (Sadler 2009; Ugazio et al 1990) Prevalence of Down syndrome Down syndrome has been seen as a major chromosomal disorder occurring in the United States. The incidence of Down syndrome found in the newborns of United States is 1 in 700. The problem is further aggravating as the genetic problem has yet not been provided with any cure. The problem of Down syndrome has increased over decades and this has been proved by a research carried out by the Centers for Disease Control and Prevention. Although women choose to end pregnancies with trisomy 21 it is still seen that the genetic problem is on the increase. It was also found that mothers with an age over 35 were more prone to the problem than the mothers who were below that age. Although the problem has been accounted to the maternal age it is still seen that the birth trends move women to give birth at an older age. The CDC reported an increase from 9 infants per 10,000 births to 11.8 in 10 diverse states of the United States of America. However on the other hand the prevalence of Down syndrome has remained steady in the United Kingdom. Prenatal diagnosis and other methods have also helped mothers to get over the problems that are associated with the syndrome. It was estimated that around 92 percent of the mothers choose abortion when they found that the embryo had trisomy 21 (James 2009). History of Down syndrome Although much has become known about Down syndrome in the recent centuries it is analyzed that the syndrome dates back to the 16th century. The condition could not be recognized in those times until finally in 1866 when Doctor John Langdon Down found about it. He analyzed that many of the children that he was treating shared certain characteristics. Before the syndrome was identified the families of these children used to dump them in large institutions and these children were then put with crime perpetrators. It was then in 1800 that reformists came to know that these slow children could also make progress in the field of education. An American known as Samuel Gridley Howe put forward that these children should also learn while they are in their respective institutions. Gradually with time the awareness about disabled children increased. Eduard Seguin a French doctor wrote about children suffering from Down syndrome in the following words “milk-white, rosy, and peeling skin….truncated (shortened) fingers and nose; with its cracked lips and tongue…skin at the margin of the lids”. In the same year John Down described children who had the same characteristics and were suffering from mental retardation. He believed that these children have an immense power to mimic and they can study if they are provided with the right environment. He described these children as Mongoloids as they had slanted eyes like people of Mongolia. Although the term Mongoloids was considered racist by many it was used as a scientific term till the 1960s when finally the scientists changed the name of the disorder to Down syndrome (Brill 2007). Aspects of Down syndrome Down syndrome in itself is a major cause of mental retardation in many of the affected individuals. Individuals affected with Down syndrome usually have 47 number of chromosomes but in some cases it is seen that these individuals even have normal number of chromosomes. In these cases the extra chromosomal material is present in a segment of the chromosome and this is known as translocation. Parents who give birth to children with Down syndrome have normal karyotypes and a cause of Down syndrome is the nonmeiotic disjunction. One of the strongest risk factor which causes Down syndrome is the maternal age. It has been found that in women less than 20 years of age the incidence of Down syndrome is 1 in 1550 births whereas in women over the age of 45 years the incidence is 1 in 25 live births. In about 4% of all the cases of Down syndrome it is seen that the extra chromosome is derived from the robertosonian translocation from chromosome 21 to another acrocentric chromosome. In around 1% of the cases it is seen that the patients are mosaics which means that they have a mixture of cells with either 46 or 47 chromosomes. This mosaicism in patients results from mitotic nondisjunction of the twenty first chromosomes in embryogenesis (Robbins et al 2005). Clinical Features (Diagnostic) Children suffering from Down syndrome show a flat facial profile along with oblique palpebral fissures and epicanthic folds. These symptoms can all be witnessed in a child at birth. The physical signs revolving around the syndrome are decreased muscle tone, flattened nose, small ears, small mouth, white spots on the colored part of the eye which are also known as brushfield spots. Individuals suffering from this syndrome also show retarded physical growth as can be witnessed in the people who grow up with this syndrome as they never reach the optimum height. The effects of Down syndrome on the mind can be witnessed in the IQ of children. It is found that approximately 80% of the children have an IQ of 25 to 50. However in some cases the children do have a normal level of intelligence also. The patients of Down syndrome also show other symptoms which are related to different systems of the body. Around 40% of the patients have the problem of congenital heart disease and are susceptible to defects in the endocardial cushions of ostium primum. Atrial septal defects and atrioventricular valve malformations are also seen in these patients. The cardiac problems in these patients can lead to death in infancy or early childhood. Congestion of other tissues such as esophagus and small bowel are also seen in these patients and can lead to death in some cases (Kallen et al 1996; Robbins et al 2005). Children who have trisomy 21 are at the risk of developing acute leukemias. Both acute lymphoblastic and myeloid leukemias are common in patients suffering from trisomy 21. Patients suffering from trisomy 21 at the age of 40 and above tend to develop neuropathologic changes and these changes lead to diseases like Alzheimer disease. The link between Alzheimer disease and Down syndrome has been found by Dr Potter. Dr Potter found that the patients with Alzheimer’s disease had three chromosomes on chromosome number 21 and the patients with Down syndrome also had three chromosomes on chromosome number 21. Moreover it was also seen that patients with Down syndrome at the age of 30 to 40 develop the same symptoms as those of the patients suffering from Alzheimer Disease. Sticky amyloid protein clumps are found in both the patients of Alzheimers disease and Down syndrome. This amyloid protein is the main culprit involved in killing and degeneration of the nerve cells resulting in dementia (University of South Florida Health 2010). Moreover patients with Down syndrome also suffer from abnormal immune responses. It is because of these abnormal immune responses that these patients are susceptible to infections such as lung infections (Robbins et al 2005). Tests for Down syndrome Down syndrome is a genetic disease which can be detected with the use of different tests. It is for this purpose that two types of prenatal tests have been recommended for mothers who undergo the process of pregnancy. Screening tests and diagnostic tests have their own importance when it comes to estimating the risk of patients with Down syndrome. Screening tests usually do not give a definitive answer regarding the condition of the fetus whereas diagnostic tests can help to give a definitive answer regarding the fetus. Both of these tests carry their own pros and cons if analyzed from a rational perspective. Screening tests are cost effective and can provide a baseline to the parents so as to if they should perform other tests or not. On the other hand diagnostic tests give a definitive answer to the parents as to if their child is suffering from a condition or not. The following screening tests are used to analyze if a patient is suffering from Down syndrome or not Nuchal translucency testing: - This type of test is carried out between the 11 to 14th week of pregnancy and measures the space in the folds of tissues. In babies suffering from chromosomal abnormalities it is seen that fluid is accumulated in these folds and the space appears larger. The triple screen or quadruple screen: - In these tests the quantities of substances are measured in the maternal blood. In triple screen method three markers are taken and in quadruple screen four markers are taken into consideration. Ultrasound: - A process known as ultrasound is carried out to see the baby inside the fetus which helps in seeing any physical problems that the fetus may be suffering from. This is carried out in conjunction with the blood tests to confirm the presence of any disease or syndrome. Integrated Screen: - In this type of test results are taken from the first trimester along with blood tests of the second trimester with a quadrup screen. It gives an accurate screening result and is used at many instances (Kids Health 2011; Mayo Clinic 2011). The diagnostic tests used to check the patients are the following Chorionic Villus Sampling: - This test involves the drawing of placental fluid by passing a needle in the placenta through cervix or abdomen. The test can be performed in the first trimester or in the 8th week. The problem with this type of sampling is that it carries a greater risk of miscarriage as compared to the other tests involved in diagnostics. Amniocentesis: - This test is performed on the basis of the amniotic fluid which can be drawn between the 15 to 20 weeks of pregnancy. A needle is inserted in the abdomen and the amniotic fluid is drawn which is then used to check for chromosomal abnormalities. It also carries risks of miscarriage same as CVS. Percutaneous umbilical blood sampling (PUBS) : -This type of test involves the drawing of umbilical blood from the fetus. It is carried out after 20 weeks of pregnancy and has similar risks as those of amniocentesis (Kids Health 2011; Mayo Clinic 2011) Treatment It has been found that the individuals suffering from Down syndrome have no such cure but their quality of life can be improved with significant therapy. In recent years this therapy has proved to be quite successful in treating and prolonging the life of many individuals suffering from Down syndrome. Early intervention programs help to stimulate the necessary centers of individuals suffering from the syndrome. These programs are basically enhanced by the therapists. Individuals with Down syndrome usually show associated symptoms and these symptoms should be relieved by the processes of surgery and medicinal treatment. Antibiotics and other drugs should be recommended to the individuals so that they do not get frequent infections. Behavioral therapy is necessary for these individuals so that they learn about themselves and are able to cope up with many decisions of their life. Obesity and other problems should also be looked upon in these patients so that they do not create problems in their life. It is necessary that the female adolescents suffering from Down syndrome are given enough education regarding sexual abuse. Language skills are also taught through these different forms of behavioral therapy. These language skills can help to build up the speaking power of these individuals so that they can interact easily. It is important that the parents take great care of their child when he is suffering from this syndrome as in most of the cases it is seen that parents are the best individuals who can counsel (Medline Plus 2010; Mayo Clinic 2011). Prognosis The prognosis of Down syndrome has improved over the years as the treatment of the disease has improved. The median age of death by Down syndrome has become 47 years and has increased from 25 years (Robbins et al 2005). It is also seen that many of the children suffering from the syndrome suffer from heart defects. Severity of these heart defects can lead to early death of the children suffering from the syndrome. With the help of asymptomatic treatment the individuals suffering from this syndrome can have a prolonged life. Behavioral therapy and counseling also helps in improving their skills which they previously lacked. (Medline Plus 2010). Prevention It is necessary that genetic counseling is given to those individuals who have a history of Down syndrome in their family. The most significant risk factor in Down syndrome is the maternal age and hence information regarding this risk factor should be spread. The tests which have been mentioned above should be carried out before the pregnancy takes place so that the children do not have to suffer in their life. (Medline Plus 2010). It is believed that over time with the help of different resources and techniques a proper cure to this syndrome would be sought out. References Down Syndrome. Medline Plus 2010. Down Syndrome. Treatment and Drugs. Mayo Clinic 2011. < http://www.mayoclinic.com/health/down-syndrome/DS00182/DSECTION=treatments-and-drugs> Down syndrome. Test and Diagnosis. Mayo Clinic 2011. Down syndrome. Kids Health 2011. Down Syndrome Births Rise in U.S., CDC Reports. Susan Donaldson James 2009. ABC News. Ugazio AG, R Maccario, LD Notarangelo, and GR Burgio. "Immunology of Down Syndrome: a Review." American Journal of Medical Genetics. Supplement. 7 (1990): 204-12. Sadler, Thomas W. Langman's Medical Embryology. Lippincott Williams & Wilkins, 2009. University of South Florida Health (2010, January 15). Studies demonstrate link among Alzheimer's disease, Down syndrome and atherosclerosis. ScienceDaily. Retrieved June 8, 2011, from http://www.sciencedaily.com­/releases/2010/01/100115182639.htm Top of Form Ka?lle?n, B., Mastroiacovo, P., & Robert, E. (January 01, 1996). Major congenital malformations in Down syndrome.American Journal of Medical Genetics, 65, 2, 160-6. Bottom of Form Kumar, V., Abbas, A. K., Fausto, N., Robbins, S. L., & Cotran, R. S. (2005). Robbins and Cotran pathologic basis of disease. Philadelphia: Elsevier Saunders. Top of Form Brill, M. T. (2007). Down syndrome. New York: Marshall Cavendish Benchmark. Bottom of Form Read More