Effect of genotype and Previous GH treatment on adiposity in adults with prader-willi syndrome

Abstract

Context: Adults with Prader-Willi syndrome (PWS) have an increased proportion of sc fat mass compared with body mass index (BMI)-matched controls, but whether the genotype influences body composition and metabolic profile remains controversial. Objective: To assess body composition and metabolic features in adults with PWS, according to genetic subtype. In addition, the effect of previous GH treatment was assessed. Main Outcomes and Measures: Body composition (Dual Energy X-ray Absorptiometry) and metabolic parameters were compared in PWS adults (mean age, 25.5 ± 8.9 y) with deletion (n = 47) or uniparental disomy (UPD) (n = 26), taking into account GH treatment in childhood and/or adolescence. In subgroups, adipocyte size, fasting total ghrelin levels, and resting energy expenditure were measured, and hyperphagia was assessed by the Dykens Hyperphagia Questionnaire. Results: In the whole sample, the deletion group had a higher BMI compared withUPD(40.9±11.5 vs 34.6 ± 9.6 kg/m2, P = .02), but there was no difference between groups in percent body fat, metabolic profile, adipocyte size, resting energy expenditure, hyperphagia score, or ghrelin levels. In subjects previously treated with GH, BMI was not different between UPD and deletion groups (33.0±9.7 vs 33.5±11.1 kg/m2). In addition, previousGHtreatment was associated with decreased percent body fat and adipocyte volume only in the deletion group. Conclusion: Adeletion genotype in adults withPWSis associated with increased BMI.GHtreatment in childhood and/or adolescence limits this deleterious phenotypic effect with improved adiposity markers. This study suggests relationships between the molecular phenotype of PWS and adipose tissue development as well as sensitivity to GH.