Down's syndrome

a condition resulting from a genetic abnormality in which an extra chromosome is present (there are three no. 21 chromosomes instead of the usual two), giving a total of 47 chromosomes rather than the normal 46. The chances of having a Down's child are higher with increasing maternal age. Affected individuals share certain clinical features, including a characteristic flat facial appearance with slanting eyes (as in 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), short stature, and hypotonia. Many individuals also have a degree of mental handicap, although the range of ability is wide and some individuals are of normal intelligence. Associated abnormalities, including heart defects (which affect about 40% of Down's children), intestinal malformation, deafness, and squints, may also be present.
prenatal diagnosis of Down's syndrome can be obtained by amniocentesis, chorionic villus sampling, the triple marker test, and nuchal thickness scanning; the condition can be confirmed by chromosomal analysis. Down's syndrome can also occur as a result of chromosomal re-arrangement (translocation) and as part of a mosaicism. Medical name: trisomy 21.
J. L. H. Down (1828-96), British physician

Medical dictionary. 2011.

Look at other dictionaries:

  • Down's syndrome — Down syndrome a condition resulting from a chromosomal abnormality most commonly due to the presence of three copies of chromosome 21 (trisomy 21), which is most likely to occur with advanced maternal age. Down s syndrome can also occur as a… …   The new mediacal dictionary

  • Down's syndrome — Down syndrome Down syn drome, Down s syndrome Down s syn drome, n. (Med.) A congenital disorder caused by an extra chromosome 21 in some or all cells. It causes a variable number and degree of abnormalities, including retarded growth, mental… …   The Collaborative International Dictionary of English

  • Down's syndrome — ► NOUN Medicine ▪ a congenital disorder causing intellectual impairment and physical abnormalities. USAGE Down s syndrome is the accepted term in modern use, and former terms such as mongol and mongolism, which are likely to cause offence, should …   English terms dictionary

  • Down's syndrome — Down s ,syndrome noun uncount DOWN SYNDROME …   Usage of the words and phrases in modern English

  • Down's syndrome — Down s .syndrome n [U] [Date: 1900 2000; Origin: J. H. L. Down (1828 96), English doctor] a condition that someone is born with, that stops them from developing in a normal way, both mentally and physically …   Dictionary of contemporary English

  • Down's Syndrome — 1961, from J.L.H. Down (1828 1896), English physician; chosen as a less racist name for the condition than earlier MONGOLISM (Cf. mongolism) …   Etymology dictionary

  • Down's syndrome — N UNCOUNT Down s syndrome is a disorder that some people are born with. People who have Down s syndrome have a flat forehead and sloping eyes and lower than average intelligence. (in AM, usually use Down syndrome) …   English dictionary

  • Down's syndrome —    a congenital disorder due to a chromosome deficiency    This is an example of a phrase incorporating syndrome being used to avoid a taboo word in this case what was formerly known as Mongolism. Here the stigma and the possible racial sneer are …   How not to say what you mean: A dictionary of euphemisms

  • Down's syndrome — noun Medicine a congenital disorder causing intellectual impairment and physical abnormalities including short stature and a broad facial profile. Origin 1960s: named after the 19th cent. English physician John L. H. Down. Usage Of relatively… …   English new terms dictionary

  • Down's syndrome — UK [ˈdaʊnz ˌsɪndrəʊm] / US [ˈdaʊnz ˌsɪndroʊm] noun [uncountable] medical a medical condition that someone is born with, that makes them develop in a different way from most people, mentally and physically. Down s syndrome is often simply called… …   English dictionary


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