Visualizing skull in prenatal mice with syndromic craniosynostosis

Abstract

Crouzon syndrome is characterized by premature fusion of multiple cranial sutures and profound facial dysmorphology. Improved treatment requires better understanding of the mechanisms of malformation. This study quantifies the progression of cranial dysmorphology in the Fgfr2+/C342Y mouse model of Crouzon syndrome. Samples of affected and wild‐type littermates were obtained at six developmental time points: E15.5, E17.5, P1, P7, P14, and adult. 3D reconstructions of the skull were created from microCT images using density thresholds. However, as this technique is dependent on the ossification of bone, and dysmorphology may arise earlier in development, we applied a novel method that allows us to visualize developing cranial tissues. Specifically, E15.5 samples were treated with radioopaque stain prior to microCT imaging, and cranial primordia were segmented manually. Morphometric analysis (EDMA) was used to compare shape of affected and wild‐type samples at each time point.Results indicate that dysmorphology originates in the prenatal period, when significant differences are apparent in the anterior cranial base and, to a lesser extent, the face. Significant brachycephaly becomes evident postnatally. These results confirm that dysmorphology in the mouse model of Crouzon syndrome arises prior to the bony fusion of the sutures, and that the primary defect may be localized to the anterior cranial base.