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Trisomy 21 Down Syndrome

Trisomy 21 Down Syndrome. Defining Down Syndrome: *A genetic, chromosomal disorder, specifically involving a third, extra copy of the 21 st chromosome. *Causes mental retardation and slower physical development.

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Trisomy 21 Down Syndrome

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  1. Trisomy 21Down Syndrome

  2. Defining Down Syndrome: *A genetic, chromosomal disorder, specifically involving a third, extra copy of the 21st chromosome. *Causes mental retardation and slower physical development. *Specifically known to affect the central nervous system, the heart, skeletal system and the muscle development in children. *Abnormalities in facial appearance such as slanting of the eyes, smaller than average skull and protruding tongue. *Children diagnosed with the condition have been known to be lacking muscle tone and have loose joints. *Down syndrome affected people have also been known to develop heart conditions later in life. *Despite being genetic, Down Syndrome is rarely inherited.

  3. (http://www.biotechnologyonline.gov.au/popups/img_trisomy21.cfm)‏(http://www.biotechnologyonline.gov.au/popups/img_trisomy21.cfm)‏ *Note there are are 3 chromosomes on the 21st set.

  4. The History: *Down Syndrome was named after John Langdon Down, a British doctor, in 1887. Before this time, the condition was formally known as Mongolism. [Engel(2008)] *The true cause of the condition being that there is an extra chromosome on the 21st set was not discovered until 1959 by a French physician named Jerome Lejeune. [Engel (2008)] *This extra chromosome causes the total number of chromosomes of a person wit Down Syndrome to be 47 rather than the typical 46. *The condition occurs in roughly 1/750 births in the United States. [NADS(2008)] *Over 350 000 people in the USA have Down Syndrome with more and more each year being able to maintain jobs and are able to live independently. [NADS(2008)]

  5. What are Causes of the Condition: *Studies have shown that women over the age of 35 are more likely to have a child with Down Syndrome than younger women. (Roughly 20% of all Down Syndrome births come from women over the age of 35). [NDSS(2008)] *With women over the age of 45, a child born with Down Syndrome occurs 1/35 births. [NDSS(2008)] *In 5% of cases, the father is responsible for the child's extra chromosome. *Although Down Syndrome is rarely inherited, parents already with a child with the condition are often suggested to seek genetic counselling. [MDAdvice(2008)] *The condition is specifically caused by there being an extra chromosome in the fertilized egg. This abnormality causes complications as the child develops

  6. Exploring the Causes (Continuation): *In a more scientific sense Down Syndrome is due to an error during the meiotic process known as Nondisjunction. *Non Disjunction is an error that can take place during anaphase I or anaphase II. Specifically, nondisjunction is when the joined chromosomes fail to separate properly. Therefore the result is either too many or too few chromosomes in the daughter cells. * 95% of all cases of Down Syndrome are due to the error known as nondisjunction. [NADS(2008)] * Two other types of Trisomy 21 are Robertsonian Translocation and Mosaicism. [NADS(2008)] *Both of these cases are results of a person having only partial Trisomy 21. In Mosaicism, some cells may have Trisomy 21, while others do not.

  7. Associated Complications: *Increased chances of developing: *50% of children with Down Syndrome experience hearing and or vision problems. *1/4 people over the age of 35 with Down Syndrome develop Alzheimer's Disease. [MDAdvice(2008)] *Acute Leukemia [MDAdvice(2008)] *Thyroid Disorder [MDAdvice(2008)] *Congenital Heart Defect [MDAdvice(2008)] *Heart Failure [MDAdvice(2008)] *Pulmonary Hypertension (increased blood pressure in the lungs)‏

  8. The Diagnosis: *There are 2 types of testing performed when diagnosing someone with Down Syndrome: Screening and Diagnostic tests. Screening: *Triple Screen: Measures the various substances that are found in your blood. A Triple Screen is composed of 3 smaller tests. [NADS(2008)] *Ultra sounds: Show physical traits that increase the likelihood of having a child with Down Syndrome. [NADS(2008)] Diagnostic: *Chronic Villus Sampling: Performed between 8-12 weeks of pregnancy. [NADS(2008)] *Amniocentesis: Performed between 12-20 weeks of pregnancy. [NADS(2008)] *Percutaneous Umbilical Blood Sampling: Performed after 20 weeks of pregnancy. [NADS(2008)]

  9. The Diagnosis Continued What is involved in each diagnostic test? *Chronic Villus Sampling: Detects chromosomal irregularities through a process of extracting pieces from the woman's placenta. These pieces of the placenta have DNA of the developing baby. [NADS(2008)] *Amniocentesis:A needle is inserted through the abdominal wall and into the uterus. Here fluid from the sac enclosing the fetus is withdrawn for analysis. [NADS(2008)] *Percutaneous Umbilical Blood Sampling: A needle is used to withdraw blood from the vein in the umbilical cord. The sample can then be analyzed for chromosome abnormalities that may result in Down Syndrome. [NADS(2008)]

  10. Treatment: *Down Syndrome is a chromosomal disorder; consequently there is no medication that will treat it at this time. *Fortunately there are plenty of forms of medication that will treat the many complications that coexist with the condition. *Because children affected by Down Syndrome often develop at a slower rate, speech therapy, special education and physical therapy may help with the developmental process. *One of the most stimulating things that a parent can do for a child with Down Syndrome is to push them to stay as active as possible. *People with Down Syndrome can achieve just as great things as those without the condition can, they just require more time.

  11. What Does the Future Hold For Down Syndrome: *Currently studies are showing that people with Down Syndrome may benefit from something called medical intervention. *Medical Intervention: Medical Intervention is simply a process of treatment used by aiding medicine. With the aid of amino acid supplements, and a drug known as Piracetam, children with Down Syndrome may be able to benefit. [NICHD(2008)] * Piracetam is a drug that may be able to improve a child's cognitive function (the ability to think and process information). [NICHD(2008)] Laboratory mice have also been used recently for studying other possible treatments. [NICHD(2008)] Scientists are able to study the developmental process of mice with the condition because the genes of a mouse's 16th chromosome are very similar to those of a human's 21st. [NICHD(2008)]

  12. Conclusion: *As expressed earlier in the presentation, more and more people affected by Down Syndrome are able to live successful and fulfilling lives. *With the help of friends and family, can live happily while coping with their condition. *As science continues to improve, and our knowledge widens, maybe sometime in the future, this condition will be treated completely.

  13. Works Cited ________(2008).Down Syndrome. In Dorland's Illustrated Medical Dictionary. 30th Edition. Philadelphia, W.B. Saunders and Company. ________(2002). Down Syndrome. In Health Matters! (Vol 8 pp78). Danbury, Connecticut: Grolier ________(2008).Down Syndrome. Retrieved April 8,2008 from Kids Health For Kids. Website http://www.kidshealth.org/kids/health_problems/birth_defect/down_syndrome.html ________(2008).Down Syndrome. Retrieved April 10,2008, from MD Advice Website: http://www.mdadvice.com/library/symp/illness178.html ________(2008). Down Syndrome. Retrieved April 12, 2008 from University of Maryland Medical Centre. Website: http://www.umm.edu/ency/article.000997.htm Engle,June, Down Syndrome(2005). The Complete Canadian Health Guide (pp 316-317) The Governing Council of the University of Toronto. _______(2008). Facts About Down Syndrome. Retrieved April 9, 2008 from National Association for Down Syndrome. Website: http://www.nads.org/pages_news/facts.html

  14. ______(2008). Facts About Down Syndrome. Retrieved April 15 2008 from National Institute of Child Health and Human Development. Website: http://www.nichd.nih.gov/publications/pubs/downsyndrome.cfm _______(2005). How Does Down Syndrome Occur? In Encyclopedia of Family Health (Vol 2, pp206). New York: Marshal Cavendish _______(2008). Information Topics. Retrieved April 10 2008 from National Down Syndrome Society. Website: http://www.ndss.org/index.php?option=com__content&task=view&id=1812&ltemid=95

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