Adiposity indices in German children and adolescents with genetically confirmed Prader-Willi syndrome (PWS)

BACKGROUND: Morbid obesity develops as a result of hyperphagia and compulsi ve eating behavior in patients with Prader-Willi syndrome (PWS), if caloric intake is not rigorously controlled. PWS-specific centile curves for adipo sity indices constructed in the past were based on clinically diagnosed pat ients. With the advent of molecular genetic methods, allowing for an unequi vocal diagnosis, new PWS curves based exclusively on molecularly diagnosed patients are becoming available, eliminating a potential diagnostic bias. OBJECTIVE: To compare fat distribution in molecularly confirmed German PWS patients to that of clinically diagnosed American PWS patients and a health y reference population DESIGN: Cross-sectional anthropometric study. SUBJECTS: One hundred German patients (49 F) with molecularly confirmed PWS (age: < 30y). MEASUREMENTS: Triceps (subscapular) skinfold thickness, waist and hip circu mference. RESULTS: Skinfold thickness was massively elevated in the majority of the m olecularly confirmed German PWS patients compared to a healthy reference po pulation. Whereas triceps skinfold thickness was in good agreement with Ame rican PWS patients, subscapular skinfold thickness in German girls rose ear lier than in American PWS girls, indicating possible differences between ca loric intake or the proportion of patients entering puberty spontaneously. Waist circumference and waist-hip ratio (n = 89) were elevated in a relativ e small proportion of patients only and did not reflect lower abdominal fat . This may be due to the peculiar shape of many patients with a typical fat accumulation around the buttocks. CONCLUSIONS: In addition to body mass index, use of skinfold thickness is r ecommended for follow-up of dietary interventions in PWS.