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Down's syndrome Line breaks: Down's syn|drome
(also Down syndrome)

Definition of Down's syndrome in English:


[mass noun]
A congenital disorder arising from a chromosome defect, causing intellectual impairment and physical abnormalities including short stature and a broad facial profile. It arises from a defect involving chromosome 21, usually an extra copy (trisomy-21).
Example sentences
  • This is an accurate way of finding out whether the baby has a number of genetic or inherited disorders, such as Down's syndrome or cystic fibrosis.
  • In Down's syndrome, an extra copy of chromosome number 21 is included when the sperm and the egg come together to form the embryo.
  • For that reason society offers testing for Down's syndrome, haemophilia, cystic fibrosis, and a range of other genetic conditions.


Of relatively recent coinage, 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 be avoided.


1960s: named after John L. H. Down (1828–96), the English physician who first described it.

Definition of Down's syndrome in:
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