Down's+Syndrome


 * Introduction**

Trisomy 21, also known as Down’s syndrome, is a condition due to an additional full or partial copy of chromosome 21. An extra chromosome could be caused by mutation or non-disjunction during anaphase of meiosis, most commonly seen in the development of eggs in older women. Down’s syndrome is the most common chromosomal disease in humans and is often accompanied by other conditions. A flow chart depicting the pathway of the disease is shown in Figure 1.




 * Historical Background**

Down’s syndrome was first described by Jean Etienne Dominique Esquirol in 1838 and Edouard Seguin in 1844. Down’s syndrome is named after John Langdon Down. Down was a British physician who was the first to fully describe the condition in 1866. It wasn’t until 1959 that Dr. Jérôme Lejeune identified chromosome 21 as the cause for Down’s syndrome. For many years, those affected by Down’s syndrome were put into homes or institutions or excluded from society. It wasn’t until the 1960s were those individuals more integrated into society.


 * Symptoms**

The symptoms of Trisomy 21 usually include slow or poor development of cognitive ability and physical growth. It can also cause mental retardation. Those affect by Down’s syndrome often of one or many types of physical abnormalities. These can include small ears, small mouth, flattened nose, upward slanting eyes, decreased muscle tone, wide and short hands with short fingers, and separated joints between the bones of the skull, among others. It can also have social effects such as a short attention span, impulsive behavior, slow learning and poor judgment.

Those with Down’s syndrome are susceptible to many other diseases because of the extra chromosomal DNA. These include many types of heart disease, thyroid diseases, cancers, gastrointestinal issues, sight and hearing issues, and infertility in males.


 * Treatment**

There is no defined standard of treatment for those with Trisomy 21. Because of the complications that may or may not accompany the condition, all treatments are unique to each patient. Many require surgery even as infants due to some of the possible physical complications. There are medicinal and behavioral guidelines for parents with children affected by the condition.


 * Conclusion and Current Reserch**

Down’s syndrome has been recognized by countries all over the world that have started annual awareness days for the disease. Some notable people with the disease include the actors Pablo Pineda, Stephane Ginnsz, Paula Sage, Tommy Jessop, Andrea Friedman, and sculptor artist Judith Scott.

There is much research still being done on Trisomy 21. The article “Down syndrome: searching for the genetic culprits1” examines the effect of different parts and amount of the duplicate chromosome. The article “Down Syndrome: From Understanding the Neurobiology to Therapy2” explored the additional chromosome’s effect on brain structure, creating a stepping stone to research in therapy. The article “Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting3” concerns a new method of detecting the possibility of Down’s syndrome by testing the would-be mother’s blood.


 * References**

1. Lana-Elola, E.; Watson-Scales,S.D.; Fisher, E.M.C.; Tybulewicz, V.L.G. (2011) “Down syndrome: searching for the genetic culprits” //Disease Models and Mechanisms// 2. Gardiner, K.; Herault, Y.; Lott, I.T.; Antonarakis, S.E.; Reeves, R.H.; Dierssen, M. (2010) “Down Syndrome: From Understanding the Neurobiology to Therapy” //The Journal of Neuroscience// 3. Ehrich, M.; Deciu, C.; Zwiefelhoferb, T.; Tynan, J.A.; Cagasan, L.; Tim, R.; Lub, V.; McCullough, R,; McCarthyb, E.; Nygren, A.O.H.; Deanb, J.; Tang, L.; Hutchison, D.; Lu, T.; Wang, H.; Angkachatchai, V.; Oeth, P.; Cantor, C.R.; Bombard, A.; Van Den Boom, D. (2011) “Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting” //American Journal of Obstetrics and Gynecology//