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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Mosaic Trisomy 21: A Case Study

There is Trisomy 21, Mosaic Trisomy 21 and Translocation Trisomy 21. Trisomy 21 is counted for 90% of the cases of Down Syndrome. This occurs when an extra chromosome is developed in either the egg or the sperm. When the egg and sperm unite there are three chromosomes 21 meaning each cell will have the extra chromosome in it. Mosaic Trisomy 21 is the rarest form it is less than 2% of all cases of Down Syndrome. In Mosaic Trisomy 21 instead of all of the cells having the…

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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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Trisomy Research Paper

The term trisomy is defined as having 47 chromosomes resulting from each body cell containing an extra copy of one chromosome. The most common trisomy is 21, better known as Down syndrome. A less common trisomy is known as Edward’s syndrome. (McKinney, James, Murray, Nelson, & Ashwill, 2013). This extra chromosome negatively affects the developmental pattern and has the potential to be life-threatening, even before the baby is born (What is Trisomy 18?, 2015). Trisomy 18 is a condition that causes…

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Down Syndrome Research Paper

Down Syndrome is a common disorder that occurs or caused when person has an extra copy of chromosome 21 in the nucleus of their cells (3 in total). It can also be caused when chromosomes fail to separate during meiosis. People with Down Syndrome would have some degree of mental retardation, a disability of people with below average IQ or mental ability. People with Down Syndrome have physical appearances like low muscle tone, small stature, and upward slanted eyes. About 1 out of every 700 babies…

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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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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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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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Trisomy 18: Edward's Syndrome

Abstract Trisomy is a condition in which an extra copy of a chromosome is present in the cell nuclei. Trisomy 18 or Edward’s Syndrome is a chromosomal disorder caused by an extra 18th chromosome. A chromosome is a structure of nucleic acids and proteins found in the nucleus of a cell that carries genes. This extra 18th chromosome can cause major physical abnormalities and severe mental retardation. The extra chromosome is a genetic error resulting from a mistake in egg or sperm formation. If a child…

Words 1322 - Pages 6