Prader Willi Syndrome
Prader–Willi syndrome (abbreviated PWS) is a rare genetic disorder in which seven genes (or some subset thereof) on chromosome 15 (q 11–13) are deleted or unexpressed (chromosome 15q partial deletion) on the maternal chromosome. It was first described in 1956 by Andrea Prader (1919–2001), Heinrich Willi (1900–1971), Alexis Labhart (1916), Andrew Ziegler, and Guido Fanconi of Switzerland. Characteristic of PWS is "low muscle tone, short stature, incomplete sexual development, cognitive disabilities, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity." The incidence of PWS is between 1 in 25,000 and 1 in 10,000 live births. The paternal origin of the genetic material that is affected in the syndrome is important because the particular region of chromosome 15 involved is subject to parent of origin imprinting, meaning that for a number of genes in this region only one copy of the gene is expressed while the other is silenced through imprinting. For the genes affected in PWS, it is the paternal copy that is usually imprinted or silenced, while the maternal copy is expressed..
No comments:
Post a Comment