Objective To evaluate the course of sleep disordered breathing (SDB) in infants with Prader-Willi syndrome (PWS).

Design Retrospective longitudinal observational study.

Setting Sleep laboratory at The Hospital for Sick Children, Toronto, Canada.

Patients Infants with PWS.

Main outcome measures The natural history of SDB in infants with PWS within 2 years from baseline assessment.

Results We identified 28 (12 male) infants with PWS who had a baseline polysomnography (PSG) at a median age (interquartile (IQR)) of 0.9 (0.5, 1.1) years. The median central apnoea index (CAI) at baseline was 6.6 events/hour (IQR 2.6, 12.1). Of these, 15/28 (53%) infants with PWS were diagnosed with significant central sleep apnoea (CSA) (CAI≥5 events/hour). Median age (IQR) at follow-up PSG was 2.1 (1.5, 2.6) years. The median CAI improved from 6.6 to 2.3 events/hour (p<0.0001). Only four infants with PWS had persistent CSA at the time of the follow-up PSG. Furthermore, three infants with PWS were diagnosed with mild-to-moderate obstructive sleep apnoea (OSA) that has improved at follow-up studies whereas two patients with PWS with no evidence of OSA at baseline were diagnosed with severe OSA on the follow-up PSG requiring adenotonsillectomy. The overall median obstructive apnoea–hypopnoea index was similar between baseline and follow-up studies (0.6 and 0.8, respectively, p=0.91).

Conclusions CSA is prevalent in infants with PWS but usually improves with age. However, these patients continue to require ongoing PSG surveillance because some infants will have persistent CSA and others are at risk of developing OSA.