Objective: The objective of the study was to provide recommendations for the diagnosis and management of Prader-Willi syndrome throughout the life span to guide clinical practice. Participants: An open international multidisciplinary expert meeting was held in October 2006 in Toulouse, France, with 37 invited speakers and session chairs (see Acknowledgments) and 85 additional registered participants. The meeting was supported by an unrestricted educational grant from Pfizer. Evidence: Invited participants with particular expertise reviewed the published evidence base for their specialist topic and unpublished data from personal experience, previous national and international PWS conferences, and PWS Association clinical advisory groups. Sessions covered epidemiology, psychiatric, and behavioral disorders; breathing and sleep abnormalities; genetics; endocrinology; and management in infancy, childhood, transition, and adulthood. Consensus Process: This included group meetings including open discussion after each session. The guidelines were written by the Scientific Committee (authors), using the conclusions provided by the sessions chairs and summary provided by each speaker, including incorporation of changes suggested after review by selected meeting participants (see Acknowledgments). Conclusions: The diagnosis and management of this complex disorder requires a multidisciplinary approach with particular emphasis on the importance of early diagnosis using accredited genetic testing, use and monitoring of GH therapy from early childhood, control of the food environment and regular exercise, appropriate management of transition, consideration of group home placement in adulthood, and distinction of behavioral problems from psychiatric illness.

In this study we assessed different magnetic resonance imaging (MRI) scanning regimes and examined some of the assumptions commonly made for measuring body fat content by MRI. Whole body MRI was used to quantify and study different body fat depots in 67 women. The whole body MRI results showed that there was a significant variation in the percentage of total internal, as well as visceral, adipose tissue across a range of adiposity, which could not be predicted from total body fat and/or subcutaneous fat. Furthermore, variation in the amount of total, subcutaneous, and visceral adipose tissue was not related to standard anthropometric measurements such as skinfold measurements, body mass index, and waist-to-hip ratio. Finally, we show for the first time subjects with a percent body fat close to the theoretical maximum (68%). This study demonstrates that the large variation in individual internal fat content cannot be predicted from either indirect methods or direct imaging techniques, such as MRI or computed tomography, on the basis of a single-slice sampling strategy.