Downs’ syndrome
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Down syndrome is set of mental and physical symptoms that result from having an extra copy of Chromosome 21.
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It is named after John Langdon Down, the British doctor who described the syndrome in 1866.
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The disorder was identified as a chromosome 21 trisomy by Jerome Lejeune in 1959.
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The chromosome nomenclature is 47, +21 for Down Syndrome
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Other names people use for Down syndrome
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Down's Syndrome
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47,XX,+21
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47,XY,+21
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How do people get Down syndrome?
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If a pair of number 21 chromosomes fails to separate during the formation of an egg (or sperm), that egg (or sperm) unites with a normal sperm (or egg) to form an embryo, that embryo ends up with three copies of chromosome 21 instead of the normal two.
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In rare cases Down syndrome is caused by a Robertsonian translocation, which occurs when the long arm of chromosome 21 breaks off and attaches to another chromosome at the centromere.
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The carrier of such a translocation will not have Down syndrome, but can produce children with Down syndrome.
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What are the symptoms of Down syndrome?
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People with Down syndrome have very distinct facial features: a flat face, a small broad nose, abnormally shaped ears, a large tongue, and upward slanting eyes with small folds of skin in the corners.
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Health concerns for individuals with Down syndrome include a higher risk for : respiratory infections, gastrointestinal tract obstruction (blocked digestive tract), leukemia, heart defects, hearing loss, hypothyroidism, and various eye abnormalities.
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Individuals with Downs’ syndrome are mentally retarded and are also called Mongoloid idiots because their facial features resemble those of Mongoloid race.
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They also exhibit moderate to severe mental retardation; children with Down syndrome usually develop more slowly than their peers, and have trouble learning to walk, talk, and take care of themselves.
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Because of these medical problems most people with Down syndrome have a decreased life expectancy. About half live to be 50 years of age.
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Last modified: Saturday, 23 July 2011, 6:53 AM