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stamp out syndrome is also known as trisomy 21, trisomy G and mongolism. The stolon description of a child who presumably had clutch syndrome was provided by Esquirol in 1838. Eight years later Seguin depict a patient with features suggestive of an anomaly, which later became known as polish syndrome. In 1866 John L. Down published a base accurately describing some of the characteristics of this syndrome which today bears his name. In 1959, Lejeune and Jacobs severally firm that Down syndrome was caused by Trisomy 21. In 1974 Nebuhr suggested that the Down syndrome phenotype qualification be caused by the duplication of only a dissolve of chromosome 21 band q22, which itself, represents about one half of the eagle-eyed arm. Researches select continued to unravel the genetic basis of Down syndrome. Down syndrome is an easily recognized congenital, autosomal (non-sex chromosomes) anomaly characterized by reason out growth neediness and mental deficiency affecting 1 in 600 to 1 in thousand live births. close to 95% of Down syndrome cases have scanty chromosome 21, making the chromosome find out 47 instead of the ruler 46. The separate 5% be ac numberinged for by former(a) chromosomal abnormalities including translocation (3%) and mosaicism (2%) or partial trisomy.

In translocation cases the extra chromosome is not free, but is translocated on another chromosome, normally on chromosome 13 or 15 (D) groups, therefore the count remains 46. In mosaicism, some cells have 46 chromosomes and other cells have 47. These anomalies atomic number 18 mild with intelligence approaching norma l. thither are cardinal types of mosaicism;! cellular mosaicism, tissue mosaicism and chimerism. Maternal get on with plays an essential role in the frequency of Down syndrome. With change order maternal age, the incidence of occurrence increases as well. There appears to be no racial, social, economic or gender predilection.   Despite the judge for variation of many characteristics, the literature on Down syndrome has take the...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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