Introduction Patients with Prader Willi syndrome are predisposed to problems with ventilatory control and sleep disordered breathing. This may be further impacted by the commencement of growth hormone in infancy. As a result early monitoring with sleep study is indicated, however it can be challenging to effectively council families about the expected results in the first few months of life due to the paucity of data pertaining to infants reported in the literature.

Methods We retrospectively collected first sleep study and demographic data from 36 children with a confirmed diagnosis of Prader Willi syndrome as determined by tertiary endocrine assessment and genetic variant.

Results The clinical characteristics and sleep study parameters are described in table 1. Whilst the median results related to both gas exchange and ventilation are reassuring, 6 (23%) patients of the 26 who had a breakdown of their AHI had an OAHI >5, with a maximum recorded OAHI of 27.7. Six (23%) of the 26 who had a breakdown of their AHI had a CAHI >5, with a maximum recorded CAHI of 9.9

Discussion This data shows that whilst the majority of patients who undergo baseline sleep study for Prader Willi syndrome will have a normal result, 23% may be expected to have an excess of obstructive events. This project may serve as useful pilot data to help council families ahead of the initial sleep study. It is our intention to follow these patients and collect longitudinal data to determine if baseline results are predictive of future need for respiratory support or response to growth hormone.