Down Syndrome

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May 16, 2013
SSN Peer Partner Final Project
Down syndrome is a chromosomal condition in which an individual possesses extra genetic material, specifically an extra complete or partial duplicate of chromosome 21 in some or all of an individuals cells. This results in several hallmark characteristics and acute cognitive affects. Some of the physical traits associated with the syndrome are a small body, especially head and ears, hypotonia, hands that are broad and short, epicanthal folds, abnormalities of the ear, and nasal bridges that are flat in shape. There are also several orofacial characteristics such as a protruding tongue that occurs as a secondary characteristic to having a small and narrow palate (Saenz). These are just some of the physical characteristics commonly seen in the chromosomal condition, but the actual presentation of physical characteristics is highly individualized. Down Syndrome is the most common chromosomal condition, affecting one in every 691 babies born in the United States and over 400,000 individuals live with the chromosomal condition in the United States (“Ear, Nose and Throat and Down Syndrome”, Fogle 281). There is a slightly higher incidence of Down Syndrome in boys than girls. Infants are often diagnosed at birth by the occurrence of physical characteristics, but the actual expression of Down Syndrome varies considerably, and the diagnosis may be delayed if too much importance is put on only the typical physical characteristics. The diagnosis will be later confirmed through the use of “genetic karyotyping”, which determines the number of chromosomes present in the body's eukaryotic cells (Saenz 381). The first physical characteristic of the chromosomal condition that is noticeable is often the presentation of hypotonia, the prescence of which should inspire concern and spur subsequent and swift assessment. Down Syndrome is, in most cases, not an inherited condition. Down Syndrome may be caused by Trisomy 21, which refers to the condition of having a an extra copy of chromosone 21, meaning three copies, instead of two, in each cell. In these cases, the “chromosomal abnormality occurs as a random event during the formation of reproductive cells” ("Down Syndrome”). This occurrence is possible in either egg cells or sperm cells, but it is most likely to occur in egg cells, and it is the occurrence of nondisjunction, a mistake in the division of a cell, that causes a reproductive cell to contain an odd number of chromosomes (“Down Syndrome”). Likewise, Mosaic Down Syndrome is not an inherited condition. It happens in the early development stages of a fetus as a random occurrence in cell division, resulting in some cells having the normal duo of chromosome 21 copies, while some cells have three copies. In the third case, Translocation Down Syndrome, the condition may be inherited. A balanced translocation refers to the genetic material in between chromosome 21 and a different chromosome being in a different arrangement than normal that is called a “balanced translocation because there is no extra material from chromosome 21” (“Down Syndrome”). The carriers of this balanced translocation do not display signs of Down Syndrome, but they have a higher risk of giving birth to children with the chromosomal condition. The syndrome's severity ranges from the mild to moderate ranges; however, the one consistently present trait in children with Down Syndrome is mental retardation, and the syndrome is responsible for one percent of all cognitive mental retardation (Fogle 281). Despite these impairments many individuals are characterized as being generally pleasant, affectionate and happy people. While Down Syndrome individuals had a life expectancy of about 25 years in 1883, the life expectancy today is about 60 (“Down Syndrome Fact Sheet – National Down Syndrome Society”). In respect to their receptive language, children diagnosed with Down Syndrome often have language comprehension that is about...
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