Welby et al.Dysphagia in 22q11.2 Deletion Syndrome perinatal dysphagia in 22q11DS. This new recognition of persistent challenges with feeding and swallowing may provide opportunities for improved therapeutic intervention for adolescents and adults with 22q11DS, as well as others with a history of perinatal feeding and swallowing disorders.

22q11.2 Deletion Syndrome (22q11DS) is a neurodevelopmental disorder associated with cranial nerve anomalies and disordered oropharyngeal function including pediatric dysphagia. Using the LgDel 22q11DS mouse model, we asked whether sensory neuron differentiation in the trigeminal ganglion (CNgV) , which is essential for normal orofacial function, is disrupted. We did not detect changes in cranial placode cell translocation or neural crest migration at early stages of LgDel CNgV development. As the ganglion coalesces, however, proportions of placode-derived LgDel CNgV cells increase relative to neural crest cells. In addition, local aggregation of placode-derived cells increases and aggregation of neural crest-derived cells decreases in LgDel CNgV. This change in cell-cell relationships was accompanied by altered proliferation of placode-derived cells at E9.5, and premature neurogenesis from neural crest-derived precursors, reflected by increased frequency of asymmetric neurogenic divisions for neural crest-derived precursors by E10.5. These early differences in LgDel CNgV genesis prefigure changes in sensory neuron differentiation and gene expression by P8, when early signs of cranial nerve dysfunction associated with pediatric dysphagia are observed in LgDel mice. Apparently, 22q11 deletion destabilizes CNgV sensory neuron genesis and differentiation by increasing variability in cell-cell interaction, proliferation, and sensory neuron differentiation. This early developmental divergence and its consequences may contribute to oropharyngeal dysfunction including suckling, feeding and swallowing disruptions at birth and additional orofacial sensory/motor deficits throughout life.

Background: Vitamin A regulates patterning of the pharyngeal arches, cranial nerves, and hindbrain that are essential for feeding and swallowing. In the LgDel mouse model of 22q11.2 deletion syndrome (22q11DS), morphogenesis of multiple structures involved in feeding and swallowing are dysmorphic. We asked whether changes in maternal dietary Vitamin A intake can modify cranial nerve, hindbrain and pharyngeal arch artery development in the embryo as well as lung pathology that can be a sign of aspiration dysphagia in LgDel pups. Methods: Three defined amounts of vitamin A (4, 10, and 16 IU/g) were provided in the maternal diet. Cranial nerve, hindbrain and pharyngeal arch artery development was evaluated in embryos and inflammation in the lungs of pups to determine the impact of altering maternal diet on these phenotypes. Results: Reduced maternal vitamin A intake improved whereas increased intake exacerbated lung inflammation in LgDel pups. These changes were accompanied by increased incidence and/or severity of pharyngeal arch artery and cranial nerve V (CN V) abnormalities in LgDel embryos as well as altered expression of Cyp26b1 in the hindbrain. Conclusions: Our studies demonstrate that variations in maternal vitamin A intake can influence the incidence and severity of phenotypes in a mouse model 22q11.2 deletion syndrome.