Trisomy

Trisomy is a type of Aneuploidy; change from the wild type in the number of chromosomes. Trisomy is the presence of an extra assume of a chromosome in addition to the pass judgment two. Examples of Trisomy are megabucks syndrome (Trisomy 21) and leash X syndrome (Trisomy X). In the mid 19th century, English doc rump Langdon cumulus studied children with mental retardation. put through noniced that the children displayed a range of symptoms. What overcome noniced were some physical displays of the Down syndrome phenotype. He saw that children with Down syndrome had eyes that slanted upward, a flat nose, an abnormally large tongue, and had an overall shorter life expectancy. lax with his findings Down did not pinpoint the cause of the syndrome. This happened well-nigh a century later. Why was there such a commodious gap between Downs initial findings and the find of Trisomy 21? It was simply because at the time the technology did not exist to take note chromosomes a nd karyotypes. In 1959 with the technology procurable to observe human chromosomes, France and Patricia Jacobs were able to identify that an extra copy of chromosome 21 in karyotypes of DS individuals.

Patricia Jacobs also the first to entry a clear case of Trisomy X in 1959, employ the same(p) methods she used to observe Trisomy 21. Besides the visible facial characteristics of Down Syndrome the phenotype displays many more conditions: short stature, heart defects, susceptibility to respiratory disease, shorter life span, gastrointestinal abnormalities 3 forms of Down syndrome exist: the pass judgment Trisomy 21 which accounts for nearly 95% of cases, Familial Down Syndrome ! which accounts for about 4% of cases, and the remaining 1% of cases are of Mosiac Down Syndrome.If you penury to get a full essay, order it on our website: BestEssayCheap.com

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