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Down's syndrome
Down's syndrome (downz) n. a condition resulting from a chromosomal abnormality, most commonly the presence of three no. 21 chromosomes (instead of the usual two), which is more likely to occur with advanced maternal age. Affected individuals share certain clinical features, including a characteristic flat facial appearance with slanting eyes (as in the Mongolian races, which gave the former name, mongolism, to the condition), broad hands with short fingers and a single crease across the palm, malformed ears, eyes with a speckled iris (Brushfield spots), and short stature. Many individuals also have a degree of mental retardation, although the range of ability is wide. The incidence of congenital heart defects is 40–50%, and other structural malformations (e.g. duodenal atresia) and abnormalities (e.g. deafness, obesity, type 2 diabetes) may be present. Medical name: trisomy 21. [ J. L. H. Down (1828–96), British physician]
www.downs-syndrome.org.uk Website of the Down's Syndrome Trust |
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"Down's syndrome." A Dictionary of Nursing. 2008. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. "Down's syndrome." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O62-Downssyndrome.html "Down's syndrome." A Dictionary of Nursing. 2008. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-Downssyndrome.html |
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Down's syndrome
Down's syndrome A congenital form of mental retardation due to a chromosome defect in which there are three copies of chromosome no. 21 instead of the usual two (see trisomy). The affected individual has a short broad face and slanted eyes (as in the Mongolian races), short fingers, and weak muscles. Down's syndrome can be detected before birth by amniocentesis. It is named after the British physician John Down (1828–96), who first studied the incidence of the disorder.
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Cite this article
"Down's syndrome." A Dictionary of Biology. 2004. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. "Down's syndrome." A Dictionary of Biology. 2004. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O6-Downssyndrome.html "Down's syndrome." A Dictionary of Biology. 2004. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-Downssyndrome.html |
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Down's syndrome
Down's syndrome (formerly ‘Mongolism’) The condition whereby one of the small autosomes (chromosome 21 in humans) is represented three times (trisomy) instead of twice. Individuals exhibiting the syndrome have characteristic phenotypic signs. It is known only in humans, chimpanzees, and orang-utans. Presumably, trisomy of larger chromosomes is incompatible with survival.
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Cite this article
MICHAEL ALLABY. "Down's syndrome." A Dictionary of Zoology. 1999. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "Down's syndrome." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O8-Downssyndrome.html MICHAEL ALLABY. "Down's syndrome." A Dictionary of Zoology. 1999. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-Downssyndrome.html |
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