Trisomy 21 Essay example

Submitted By CJ-Almacen

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Pages: 2

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CJ Almacen
5/14/2014
Biology 101

Trisomy 21
According to genetics, the cause of Trisomy 21 is when three copies are made, rather than the usual two copies of genes on chromosome 21. Typically, parents of an individual affected with this genetic disorder are genetically normal. The chances of parents with one child affected with Down syndrome and having a second child with the syndrome as well are at 1% risk, if both parents are determined to have normal karyotypes. In Trisomy 21, there are three genetic variations of Trisomy 21 mechanisms that can occur. The first and most common (about 90% of Down syndrome cases), is known as non-disjunction, in which an extra chromosome (chromosome 21) originates in the development of either the sperm or the egg. When the sperm and the egg combine to create the fertilized egg, three (instead of two) chromosomes 21 are present. As the cell divides, the chromosome is repeated in every cell. The second genetic mechanism is known as mosaic Trisomy 21. This variation is a rare form and less than 2% of Down syndrome cases. Though there are similarities with non-disjunction, individuals with mosaic Trisomy 21 differ due to the extra chromosome 21 being present in some of the cells, not all of them. This type of mechanism occurs during abnormal cell division after fertilization. The name “mosaic” originates from a randomized order of normal and abnormal cells. During cellular mosaicism, the random combination of can be visible in different cells of the same type; while with tissue

Trisomy 21

A patient has recently delivered an infant who was diagnosed with Down syndrome or trisomy 21. While talking with the mother, you note that she is very upset and asked for more information on what that diagnosis means for her child. *What type of congenital disorder is trisomy and what are the pathophysiological theories for why it occurs? Trisomy 21 is a congenital disorder when a person is born with an extra chromosome. Normally, a baby is born with 46 chromosomes; a Down syndrome baby has a total…

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Down Syndrome Children Should Be Separated

normally. If they aren’t able to do things normally, then they should not be separated. This paper will discuss only, Down syndrome and the 3 types of Down syndrome known as the standard trisomy 21, translocation, and Mosaicism. Down syndrome can occur when there is a full or partial extra copy of chromosome 21. There are 3 different types of Down syndrome that exist. “One in every 691 babies in the United States is born with down syndrome- about 6,000 each year (National Down Syndrome Society [NDSS]…

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Down Syndrom Essay

Abstract a) Down syndrome b) Interesting topic c) Understanding why down syndrome occurs Introduction a) Who discovered Down syndrome b) What is Down syndrome Body research A. What Causes it and is it inherited? 1-Trisomy 21 2-Mosaic Down syndrome 3-Translocation Down syndrome B. How Down syndrome affects Kids 1-Physical features 2-Learning C. Risk factors 1-Advancing maternal age 2- Being carriers of the genetic translocation for Down syndrome 3-Having…

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Essay about Down Syndrome and Medlineplus Medical Encyclopedia

Syndrome Edward’s Syndrome, most commonly known as Trisomy 18, is a genetic disorder in which there is an additional copy of material of chromosome 18 (“Trisomy 18: MedlinePlus Medical Encyclopedia,” 2013). Instead of the usual two copies, there is a third copy in the person’s body. Children with Edward’s Syndrome can commonly be mistaken for having Down Syndrome because many of the symptoms are similar, but Down Syndrome lies on chromosome 21 rather than chromosome 18. Down Syndrome is also much…

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My Project Essay

some or all of a person's cells have an extra full or partial copy of chromosome 21, the result is Down syndrome. The most common form of Down syndrome is known as Trisomy 21, a condition where individuals have 47 chromosomes in each cell instead of 46. This is caused by an error in cell division called nondisjunction, which leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception. Trisomy 21 accounts for 95% of Down syndrome cases, with 88% originating from nondisjunction…

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The Origin Of Aneuploidy

studies is presented such that all the factors outlined in the first two studies support the idea that the third report suggests: an accumulation of Trisomy 21 oocytes that are developed in utero. The most commonly diagnosed mental/malformation disorder is Down syndrome which is caused by gene dosage-imbalance resulting from human chromosome-21 trisomy. In 1866, John Langdon Down was the first individual to classify and study these individuals sharing the same malformations and mental handicaps. It…

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Gene Therapy Essays

Down syndrome Down syndrome also known as Trisomy 21 is a set of mental and physical symptoms that are caused by having an extra copy of the chromosome 21. People that do not have Down syndrome have only 2 copies of the Trisomy 21, but people with Down syndrome have 3 copies. As a result of having the 3 copies instead of the 2 it will change the person’s body and brain’s normal development. Depending on the person the Down syndrome can either be a mild or severe case. Many people with Down syndrome…

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Essay about Down Syndrome and Incorrect Cell Division

body. The article states that humans have 23 pairs of chromosomes. When chromosome 21 does not divide correctly, a type of Down syndrome occurs. All types of incorrect cell division involve extra material provided by the chromosome 21. This is the first main point. The second main point is the fact that there are three genetic variations that can cause Down syndrome. The first is involved with the chromosome 21 having too many copies of it. Normally, there are only two copies of it. But when there…

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English: Chromosomes Essay

Down Syndrome Trisomy 21, one of the most common causes of mental retardation is due to an extra chromosome 21. This results in a number of characteristic features, such as short stature, broad hands, stubby fingers and toes, a wide rounded face, a large protruding tongue that makes speech difficult and mental disabilities. Individuals with this syndrome have a high incidence of respiratory infections, heart defects and leukemia. The average risk of having a child with trisomy 21 is 1/750 live births…

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Importance Of Teaching Vocabulary

of Down syndrome is a chromosomal disorder which results in different level of physical, health, and intellectual difficulties. It is also mentioned that this matter is caused by the presence of full or partial extra copy of chromosome 21 which is known as trisomy 21 too. This additional genetic material changes the process of development in individuals with extra chromosome and causes characteristics associated with Down syndrome. Common features of Down syndrome according to Health Genetics journal…

Words 710 - Pages 3