Prader-Willi Syndrome as a Model for Obesity

Zürich Switzerland - October 18-19, 2002

By Belinda Pinyerd Ph.D., R.N.

Belinda is vice president of the PWSA (USA) Ohio Chapter

Physicians and researchers from more than 20 countries met last fall in Zürich, Switzerland to discuss what is currently known about the obesity associated with Prader-Willi syndrome (PWS). The meeting was held in Zürich to honor the late Dr. Prader who, along with professors Alexis Labhart and Heinrich Willi, first described PWS in 1956 at the University of Zürich.

Other participants at the meeting included nutritionists, parents, and psychologists who are involved in the care of obese individuals. A book containing all the presentations is to be published within the next 18 months.

PWS was selected for discussion given the obesity features associated with the syndrome. In fact, researchers expressed a renewed interest in the syndrome from the standpoint that obesity is reaching epidemic proportions across the globe.

Intensive study of the special problems of obesity in PWS patients will not only be of great benefit to individuals with PWS, but also to non-PWS obese individuals. Since PWS-obesity includes both severe appetite and metabolism problems, the hope is that with a better understanding of their obesity, researchers will simultaneously learn more about obesity in otherwise normal patients.

Presentations ranged from discussions on genetics and neuropeptides to behavioral manifestations common to children and adults with PWS. Specific discussions focused on the pathogenesis of human obesity, appetite regulation, carbohydrate metabolism, autonomic nervous system feedback loops, body composition, energy expenditure, and long-term medical management.

One of the most exciting presentations reviewed the new discovery of abnormal elevations of ghrelin in patients with PWS. Ghrelin is a recently described hormone that stimulates appetite and seems to play a role in regulation of body weight. Ghrelin is normally suppressed in the obese condition and elevated in individuals who are very lean. Therefore the abnormality seen in PWS may be important. However the group was in agreement that more research needs to be performed. Several investigators are focusing on ghrelin as well as the hormone leptin since they both seem to play key roles in body fat production and appetite regulation.

As the meeting closed, excitement and enthusiasm penetrated the audience. Plans for future meetings, collaborations, and exchanges were discussed among the participants. PWS is indeed a research priority to these worldwide leaders.

Belinda Pinyerd is a medical writer from Columbus, Ohio, and is vice president of the PWSA (USA) Ohio Chapter.

INVITED SPEAKERS-COUNTRY-PRESENTATION TITLES:

• Moris Angulo – U.S.A. – Growth hormone therapy for children with PWS: Near-final height data
• Aaron L. Carrel – U.S.A. – Does hGH in PWS affect morbidities associated with obesity?
• Kenneth Ellis – U.S.A. – Assessment of body composition in children with PWS or simple obesity
• Gabriele Gillessen-Kaesbach – Germany – Epidemiological and genetic aspects of Prader-Willi Syndrome
• Jane Gilmour – U.K. – A comparison of behavior and appetite profiles in children with simple obesity and PWS
• Tony Goldstone – U.K. – Hypothalamic neuropeptides and regulation of fat mass in PWS
• Graziano Grugni – Italy – Gonadal function and its disorders in simple obesity and in PWS
• Heiko Krude – Germany – Genetics of obesity: Melanocortin pathway and implications for new pharmacological treatments
• Dagmar l’Allemand – Switzerland – Role of diet and education in young children with PWS
• Philip D. K. Lee – U.S.A. – Model for a peripheral signaling defect in PWS
• Rudolph L. Leibel – U.S.A. – Hypothalamic energy regulation: The orexigenic pathway
• Ann Christin Lindgren – Sweden – Characterization of hyperphagia in PWS
• Yves Nordmann – Switzerland – Muscle hypotonia and effects of physical training
• Bernhard Schlüter – Germany – Dysregulation of respiration in PWS
• Matthias Tschöp – Germany – A potential role for ghrelin in the pathogenesis of Prader Willi Syndrome
• Ha Trang – France – Sleep-related breathing disorders associated with childhood obesity
• Martin Wabitsch – Germany – Consequences of impaired growth hormone secretion for body composition and metabolism in obesity and PWS
• Klaas Westertrep – Netherlands – Physical activity and obesity
• Barbara Y. Whitman – U.S.A. – A comprehensive care approach including activity, behavioral and pharmacological treatment in obesity
• Stephen C. Woods – U.S.A. – Insulin and central appetite regulation
• William B. Zipf – U.S.A. – Abnormalities of insulin secretion and carbohydrate metabolism in PWS and in simple obesity