Dysmorphology in the mandible of a Crouzon mouse model

Crouzon syndrome, a craniosynostotic disease, displays similar phenotypic characteristics in both humans and model mice ( Fgfr2 C342Y/+ ). Previous analyses largely focused on dysmorphology of the calvarium and face. Mandibular defects are not as clearly defined in the literature. In humans with Crouzon syndrome, mandibles have been described variably as shorter and/or wider. This project tests the hypothesis that the Fgfr2 C342Y mutation affects both size and shape of the mandible in a mouse model. MicroCT scans were collected from skulls of 10 heterozygous mutant and 10 wild‐type littermate adult mice. Using Etdips software, 3D surfaces of the mandible were reconstructed, and coordinate data were collected for 20 landmarks. Shape and size analyses were conducted using a combination of EDMA and GLS superimposition. Results demonstrate that both size and shape of the mandible are affected by the Fgfr2 C342Y mutation. A t‐test reveals that centroid size is significantly smaller in the mutants (p<0.005). PCA demonstrates a clear separation in shape between the groups. EDMA analysis localizes these differences to a smaller anterior‐posterior ramal length and larger bi‐gonial distance in the mutants. This study shows that Crouzon syndrome affects not only the size of the mandible, but also its shape. These results may be relevant to clinical treatment of malocclusion in humans with Crouzon syndrome. Grant Funding Source : NIDCR (R03‐DE019816) and a Plastic Surgery Educational Foundation Research Grant