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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 throne syndrome was provided by Esquirol in 1838. Eight years later Seguin set forth a patient with features suggestive of an anomaly, which later became known as agglomerate 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 office be caused by the duplication of only a bulge out of chromosome 21 band q22, which itself, represents about one half of the vast 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 deficiency and mental deficiency affecting 1 in 600 to 1 in green live births. close to 95% of Down syndrome cases have unnecessary chromosome 21, making the chromosome find out 47 instead of the ruler 46. The separate 5% be ac numberinged for by new(prenominal) 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 argon mild with intelligence approaching normal. th ither are terzetto types of mosaicism; cell! ular mosaicism, tissue mosaicism and chimerism. Maternal get on with plays an measurable role in the frequency of Down syndrome. With change magnitude maternal age, the incidence of occurrence increases as well. There appears to be no racial, social, economic or gender predilection.   Despite the quiz for variation of many characteristics, the literature on Down syndrome has profane the...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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