ESPE Abstracts

Background: Prader-Willi Syndrome (PWS), due to loss of expression from genes within the PWS imprinted region at chromosome 15q11.2-13, is characterized by hypotonia and feeding intolerance in infancy with later development of hyperphagia and obesity. Growth hormone improves tone, body composition, and height and can be started in infancy. Morbidity and mortality in PWS include those secondary to hyperphagia and respiratory illness as well as a 17% reported incidence of sudden death in childhood. Choking is a known hazard with a 34% reported incidence. Despite well-described feeding intolerance in infants with PWS, there are no published reports of formal swallow studies.

Objective and hypotheses: To evaluate the swallowing function of infants with PWS seen at Seattle Children’s Hospital (SCH) with VFSS obtained for clinical indications of poor feeding. We hypothesize that VFSS will diagnose pathology missed by clinical observation and may help determine feeding safety in PWS infants.

Method: VFSS results of infants followed in the interdisciplinary SCH PWS clinic between October 2014 - April 2016 were reviewed. The study was approved by the SCH IRB.

Results: Six infants with genetically confirmed PWS underwent 10 VFSS (age: 3 weeks-15 months; gender: male 4, female 2; subtypes: deletion 3, uniparental disomy 2, imprinting defect 1). One patient received 5 studies over 14 months. Of all the studies, 100% indicated oropharyngeal phase dysphagia with abnormal pharyngeal clearance in 80% (5 infants). 100% showed silent aspiration with thin liquids, 60% with thickened liquids, 20% with purees. 60% were done while the infant was on growth hormone. Average age of growth hormone initiation was 2.5 months. The infant with multiple studies showed improvement over time, but still had an abnormal VFSS at 15 months old.

Conclusion: VFSS showed oropharyngeal phase dysphagia and silent aspiration in all infants which may have been undiagnosed with only clinical observation. Abnormalities were present despite early initiation of growth hormone. Careful consideration should be made before starting oral feeds in infants with PWS, and VFSS can be a useful clinical tool in this decision. Swallow dysfunction may be a contributor to morbidity in PWS. Further longitudinal studies are needed to characterize swallowing function in PWS over time.