Prader-Willi

Prader-Willi

Very rare genetic disorder, in which seven genes on chromosome 15 are missing or unexpressed on the paternal chromosome. It was first described in 1956 by Andrea Prader, Heinrich Willi, Alexis Labhart, Andrew Ziegler, and Guido Fanconi of Switzerland.external image praderwilli.jpg

Effects
Causes poor muscle tone, low levels of sex hormones and a constant feeling of hunger. The part of the brain that controls feelings of fullness or hunger does not work properly in people with PWS. They overeat, leading to obesity.

Signs
Babies with PWS: usually floppy, with poor muscle tone, and have trouble sucking. Boys may have undescended testicles.
Other signs of PWS: Short stature, poor motor skills, weight gain, underdeveloped sex organs, mild mental retardation, and learning disabilities.

Statistics
PWS is between 1 in 10,000 and 1 in 15,000 live births.

external image mpraderwillisymptomweb.jpgGenetics
PWS is caused by the deletion of the paternal copies of the printed SNRPN and necdin genes along with clusters of snoRNAs: SNORD64, SNORD107, SNORD108 and two copies of SNORD109, 29 copies of SNORD116 (HBII-85) and 48 copies of SNORD116 (HBII-52). These are on chromosome 15. This region (PWS/AS) may be lost by one of several genetic mechanisms which, in the majority of instances occurs through chance mutation.The risk of the sibling of an affected child of having PWS depends on the genetic mechanism which caused the disorder. The risk to siblings is <1% if the affected child has a gene deletion or uniparental disomy, up to 50% if the affected child has a mutation of the imprinting control region, and up to 25% if a parental chromosomal translocation is present.

Execise can help build muscle mass and control weight.
Most cases of PWS are not inherited, particularly those caused by a deletion in the parental chromosome 15 or by maternal uniparental disomy.



These genetic changes occur as random events during the formation of reproductive cells or in early fetal development. Affected people typically have no history of the disorder in their family. external image equation88.png

Treatments: physical therapy to improve muscle strength, strict supervision of daily food intake based on height, weight, and body mass index (BMI) to provide energy requirements and weight gain. growth hormone replacement therapy to normalize height, increase lean body mass and mobility, and decrease fat mass.



  • For additional infromation, go to:
http://www.pwsausa.org/
http://www.medicinenet.com/prader-willi_syndrome/article.htm

cv-8f-nmt: This is a little tough to understand, you don't have a video, and you didn't include the type of inheritance.
cv-8f-end: I like the use of color and the layout but you did not include the type of inheritance or videos which could make it more easy to understand.
cv-8f-ajp: Your page is neatly organized and colorful, but it needs to have the type of inheritance and some videos that would help us to understand better.
cv-8f-hjm: you had really good organization, and i appreciated the color coordination
cv-8f-kpi: the genetics part was really confusing, maybe if you would've simplified it a little bit it would've been more easy to understand. The picture on the left gave a good visual, but maybe a bigger picture next time. nice color though!
cv-8f-bop: It is very colorful and organized!!!!!!!! good job~!
cv-8f-ecb: this page has great color and oranization but it's missing the type of inheritance. besides that great job!

Bibliography: http://www.nlm.nih.gov/medlineplus/praderwillisyndrome.html
http://www.medicinenet.com/prader-willi_syndrome/article.htm
http://images1.clinicaltools.com/images/gene/praderwilli.jpg
herkules.oulu.fi/ isbn9514270274/html/x1212.html