BACKGROUND: Sleep-related breathing disorders are common in individuals with Prader-Willi syndrome (PWS). The US Food and Drug Administration approved the use of growth hormone in PWS in 2000. Many infants with PWS are being started on growth hormone therapy, but no data exist on the respiratory effects of growth hormone treatment in this age group.
STUDY OBJECTIVES: To perform overnight polysomnographic studies to evaluate the effects of growth hormone on sleep-related breathing in infants with PWS.
METHODS: Pilot study evaluating overnight polysomnography before and 6 weeks after initiation of growth hormone therapy at a dose of 1 mg/m2 per day in 20 infants from 2 to 21 months of age with genetically confirmed PWS. Polysomnography results were analyzed for frequency and severity of obstructive and central apnea and hypopnea events and the overall apnea-hypopnea index.
RESULTS: When data were analyzed for the total group, there were no significant changes in sleep-related disorders before and after institution of growth hormone therapy. However, 12 infants had an increase in the frequency of obstructive events associated with either upper respiratory infections or a diagnosis of gastroesophageal reflux at the second sleep study (after institution of growth hormone therapy). Resolution of these conditions was associated with normalization of polysomnography results on follow-up studies.
CONCLUSIONS: Overall, growth hormone therapy, per se, had no significant effect on sleep related-breathing disorders in infants with PWS. Infants with upper respiratory infections of gastroesophageal reflux may be at risk for developing more obstructive events after beginning growth hormone treatment. We recommend close monitoring of infants with PWS after they begin growth hormone therapy, especially when they have upper respiratory infections.