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

BACKGROUND: Morbid obesity develops as a result of hyperphagia and compulsive eating behavior in patients with Prader-Willi syndrome (PWS), if caloric intake is not rigorously controlled. PWS-specific centile curves for adiposity indices constructed in the past were based on clinically diagnosed patients. With the advent of molecular genetic methods, allowing for an unequivocal 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 healthy reference population.DESIGN: Cross-sectional anthropometric study.SUBJECTS: One hundred German patients (49 F) with molecularly confirmed PWS (age: <30 y).MEASUREMENTS: Triceps (subscapular) skinfold thickness, waist and hip circumference.RESULTS: Skinfold thickness was massively elevated in the majority of the molecularly confirmed German PWS patients compared to a healthy reference population. Whereas triceps skinfold thickness was in good agreement with American PWS patients, subscapular skinfold thickness in German girls rose earlier than in American PWS girls, indicating possible differences between caloric intake or the proportion of patients entering puberty spontaneously. Waist circumference and waist-hip ratio (n=89) were elevated in a relative 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 recommended for follow-up of dietary interventions in PWS.