Downs syndrome

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Down's syndrome Human condition caused by a chromosomal abnormality. It gives rise to varying degrees of mental retardation, decreased life expectancy, and perhaps physical problems, such as heart and respiratory disorders. The syndrome was first described by a British physician, J. L. H. Down. It is caused by the presence of an extra copy of chromosome 2l, and detected by counting chromosomes in the cells of the fetus during pre-natal testing. There is evidence that the risk of having a Down's child increases with maternal age. Originally called ‘Mongolism’ by Down, this term is now obsolete.