The Prader - Willi syndrome Maternal Ch 15 m EW Normal parents Normal PWS

Since the original description by Prader, Labhart, and Willi in 1956,' there have been over 700 case reports of the Prader-Willi syndrome and by the end of 1991 the PraderWilli Association were aware of 1595 affected individuals in North America.2 Estimates of prevalence vary: one group has reported a consensus figure of one in 10 000 births,3 but with modem techniques for laboratory diagnosis this estimate will probably be shown to have been too high. It is now known that the Prader-Willi syndrome results from abnormality or loss of a critical region on the proximal part of the long arm of the paternal chromosome 15. Clinically the condition is expressed as a dysmorphic syndrome that principally affects the central nervous system, and has a particular predilection for the hypothalamus. In this paper we summarise the clinical features of the Prader-Willi syndrome and present the current understanding of its molecular basis. The laboratory and clinical approaches to diagnosis are discussed, as well as some issues concerning the management of the metabolic, dietary, and growth problems.