Variations in Craniofacial and Velopharyngeal Structures Among Individuals with 22q11.2 Deletion Syndrome

Abstract

22q11.2 deletion syndrome is the most common genetic cause of velopharyngeal dysfunction. Studies examining 22q11.2 deletion syndrome have thus far primarily focused on variations in the bony framework. Limited information exists regarding the velopharyngeal muscle variations for this clinically challenging population. However, with advances in MRI, muscle and soft tissue imaging is possible. A series of experiments were thus designed to explore and validate the use of our research methodology on normal control participants and a single participant with 22q11.2 deletion syndrome, before initiating the study on a larger sample of children with 22q11.2 deletion syndrome. The overarching aims of this investigation were to examine craniofacial and velopharyngeal characteristics among children with 22q11.2 deletion syndrome and to determine whether craniofacial measures can predict velopharyngeal structure and muscle configurations in this population. This investigation represents the first large scale attempt to image children with 22q11.2 DS without sedation. The aim of Study I was to validate the use of a supine MRI scanner over an upright scanner to obtain data of interest. Study II was focused on the application of a child-friendly MRI protocol to ensure data collection on young pediatric participants without the use of sedation. The aim of Study III was to translate our child-friendly MRI scanning protocol to a clinical population and assess feasibility in a single participant with 22q11.2 deletion syndrome. Study IV assessed craniofacial and velopharyngeal characteristics among children with 22q11.2 deletion syndrome using the imaging protocol detailed in studies one, two, and three. Results from this study suggest that children with 22q11.2 deletion syndrome have several craniofacial and velopharyngeal characteristics that are significantly different compared to children with normal velopharyngeal anatomy. This investigation describes a safe and effective method to obtain MRI data in a clinically complex population without the use of sedation. Individuals with 22q11.2 deletion syndrome present with unique velopharyngeal muscle variations that may contribute to the high rate of velopharyngeal dysfunction associated with this syndrome.