Objective-22q11.2 deletion syndrome is the most common genetic cause of velopharyngeal dysfunction (VPD). Magnetic resonance imaging (MRI) is a promising method for noninvasive, three-dimensional (3D) assessment of velopharyngeal (VP) anatomy. The purpose of this study was to assess VP structure in patients with 22q11.2 deletion syndrome by using 3D MRI analysis.Design-This was a retrospective analysis of magnetic resonance images obtained in patients with VPD associated with a 22q11.2 deletion compared with a normal control group.Setting-This study was conducted at The Children's Hospital of Philadelphia, a pediatric tertiary care center.Patients, Participants-The study group consisted of 5 children between the ages of 2.9 and 7.9 years, with 22q11.2 deletion syndrome confirmed by fluorescence in situ hybridization analysis. All had VPD confirmed by nasendoscopy or videofluoroscopy. The control population consisted of 123 unaffected patients who underwent MRI for reasons other than VP assessment. Interventions-Axial and sagittal T1-and T2-weighted magnetic resonance images with 3-mm slice thickness were obtained from the orbit to the larynx in all patients by using a 1.5T Siemens Visions system.Outcome Measures-Linear, angular, and volumetric measurements of VP structures were obtained from the magnetic resonance images with VIDA image-processing software.Results-The study group demonstrated greater anterior and posterior cranial base and atlantodental angles. They also demonstrated greater pharyngeal cavity volume and width and lesser tonsillar and adenoid volumes.Conclusion-Patients with a 22q11.2 deletion demonstrate significant alterations in VP anatomy that may contribute to VPD.
Keywords
22q11.2 deletion syndrome; magnetic resonance imaging; velopharyngeal dysfunctionNormal velopharyngeal (VP) function is dependent upon multiple factors. Neuromuscular function, velar anatomy, and overall morphology of the VP port all contribute to the process of VP valving. The structural and functional integrity of each of these factors ultimately determines the adequacy of the VP mechanism as a whole. The VP port is composed of soft tissues (e.g., adenoids, lateral and posterior pharyngeal walls, velum) and their underlying bony structures (e.g., maxilla, basicranium, upper cervical spine). Alterations in one or more of these structures may be a feature of some craniofacial syndromes and may play a critical role in the pathogenesis of associated VP dysfunction (VPD).With an estimated incidence of 1 in 4000 births, the 22q11.2 deletion syndrome, also known as velocardiofacial syndrome (VCFS), is the most common genetic cause of VPD (McDonaldMcGinn et al., 1999). Affected patients present with a spectrum of functional and anatomic abnormalities that may contribute to alterations in VP valving, including cleft palate or submucosal cleft palate, palatopharyngeal hypotonia, platybasia, adenoid hypoplasia, and cervical spine abnormalities (Havkin et al., 2000). To date, however, the relative contribution of each of th...