Sleep Characteristics in Infants with Prader Willi Syndrome

Gila Hertz², Mary Cataletto¹, Moris Angulo¹

Winthrop University Hospital, Mineola, NY¹, Center for Insomnia and Sleep, Huntington Station, NY²

Background: By approximately age 3 years many patients with PWS will begin to develop obesity with subsequent sleep disordered breathing and excessive daytime sleepiness. The temporal course of sleep disturbance in PWS is not well understood. Recent polysomnographic studies have shown elevated apnea hypopnea index in young pre pubertal children with PWS (1). However, there have been no studies, to date that describe sleep architecture and sleep disordered breathing in infants (< 3 yrs) with Prader Willi Syndrome.

Purpose: The purpose of this study is to characterize sleep architecture and breathing patterns in infants with Prader Willi Syndrome less than 3 years of age and to identify developmental trends of sleep that possibly precede later abnormalities.

Procedure: Eight infants with PWS (3 boys 5 girls) under the age of 3, underwent an overnight sleep study prior to the initiation of growth hormone therapy (mean age 21.6+6mos). The following parameters were analyzed: Sleep stages, Total Respiratory Disturbance Index (RDI ), and REM RDI. Sleep parameters were then compared to those of an age and RDI matched control group (4 boys, 3 girls mean age 23.6 + 10.8.).

Results: There was no difference in sleep architecture between the infants with PWS and the infants with mild sleep disordered breathing (RDI<5). A trend was observed for REM latency to be shorter in the PWS group, but this result did not achieve statistical significance. Breathing patterns revealed mild sleep disordered breathing in the PWS group (Mean RDI= 1.62 +.86). Except for 1 infant, all patients with PWS

Mean REM RDI (4.51+3.05) was higher than total RDI (1.86+1.22) in all the studies.

Conclusions: Infants with PWS < 3 years of age, may present with mild sleep disordered breathing even before obesity develops. Like non-PWS infants with mild SDB, their sleep is lighter (increased sleep stage 1) and REM sleep is reduced as compared to normal controls. Finally infants with PWS show a trend to decreased REM latency, a sleep feature that is characteristic in sleep of adult individuals with PWS. While this represents a small sample of infants with Prader Willi Syndrome, some sleep abnormalities, previously observed in older children with PWS, may already present in a much younger age in this population. Additional studies are needed to solidify these findings and to compare their sleep to normal age matched controls.

Reference: 1. Festen, D. Sleep Related breathing disorders in prepubertal children with Prader Willi Syndrome and effects of growth hormone treatment. The journal of Clinical Endocrinoligy &Metabolism, Vol:91(12):4911-4915, 2006.