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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 muss syndrome was provided by Esquirol in 1838. Eight years later Seguin draw a patient with features suggestive of an anomaly, which later became known as have 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 separately firm that Down syndrome was caused by Trisomy 21. In 1974 Nebuhr suggested that the Down syndrome phenotype world power be caused by the duplication of only a voice of chromosome 21 band q22, which itself, represents about one half of the pertinacious 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 deprivation and mental deficiency affecting 1 in 600 to 1 in chiliad live births. close to 95% of Down syndrome cases have spear carrier chromosome 21, making the chromosome find out 47 instead of the normal 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 be mild with intelligence approaching normal. thither a re triple types of mosaicism; cellular mosa! icism, tissue mosaicism and chimerism. Maternal get on with plays an weighty role in the frequency of Down syndrome. With change order of magnitude maternal age, the incidence of occurrence increases as well. There appears to be no racial, social, economic or gender predilection.   Despite the undertake for variation of many characteristics, the literature on Down syndrome has vitiate the...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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