PWS is a complex genetic disorder that typically causes low muscle tone, short stature, incomplete sexual development, cognitive disability, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity.
How common is PWS?
It is estimated that one in 15,000 people has PWS.
The occurrence of PWS is due to lack of several genes on one of an individual's two chromosome 15s - the one normally contributed by the father. In the majority of cases, there is a deletion - the critical genes are somehow lost from the chromosome (deletion). In most of the remaining cases, the entire chromosome from the father is missing and there are instead two chromosome 15s from the mother (uniparental disomy).
Does the overeating associated with PWS begin at birth?
No. In fact, newborns with PWS often cannot get enough nourishment because low muscle tone impairs their sucking ability. Many require special feeding techniques or tube feeding for several months after birth, until muscle control improves. Sometime in the following years, usually before school age, children with PWS develop an intense interest in food and can quickly gain excess weight if calories are not restricted.
What causes the appetite and obesity problems in PWS?
People with PWS have a flaw in the hypothalamus part of their brain, which normally registers feelings of hunger and satiety. While the problem is not yet fully understood, it is apparent that people with this flaw never feel full; they have a continuous urge to eat that they cannot learn to control. To compound this problem, people with PWS need less food than their peers without the syndrome because their bodies have less muscle and tend to burn fewer calories. Unfortunately no appetite suppressant has worked consistently for people with PWS. Most require an extremely low-calorie diet all their lives and must have their environments designed so that they have very limited access to food.
What kinds of behaviour problems do people with PWS have?
In addition to their involuntary focus on food, people with PWS tend to have obsessive/compulsive behaviors that are not related to food, such as repetitive thoughts and verbalizations, collecting and hoarding possessions, picking at skin irritations, and a strong need for routine and predictability. Frustration or changes in plans can easily set off a loss of emotional control in someone with PWS, ranging from tears to temper tantrums to physical aggression.
What does the future hold for people with PWS?
With help, people with PWS can expect to accomplish many of the things their "normal" peers do - complete school, achieve in their outside areas of interest, be a productive worker under the right conditions, even move away from their family home. They do, however, need a significant amount of support from their families and from school, work and residential service providers to both achieve these goals and avoid obesity and the serious health consequences that accompany it. Even those with IQs in the normal range need lifelong diet supervision and protection from food availability.
by Dr. Deborah MacNamara (PDF)
Optimal Nutrition in Prader-Willi Syndrome
by Malanie Silverman (PPT)
GI & Metabolic Function
by Dr. Seema Kanwal (PDF)
Anxiety: Managing Worry & Facing Fears, One Step at a Time
by Dr. Kristen McFee (PDF)
Families Promoting Employment First
by the Family Support Institute (PDF)
Seeking Satiety: Healthy Eating with PWS
by Ellen Mackay (PDF)
PWS: A Primer for Psychiatrists
Prepared by the Pittsburgh Partnership
Skin Picking and PWS
Prepared by the Pittsburgh Partnership
Characterization of food intake in rare obesity disorders
Presentation by Stephanie Lau (PDF)
Living With PWS
Nutritional Care in PWS
Presentation by Karen Balko (PDF)
PWS Int'l Conference 2009
History of the BCPWSA
Presentation by Gillian Leaky (PPT)