Here we analyze late prenatal integration of brain and skull in two mouse models of craniosynostosis: the Fgfr2+/S252W Apert syndrome mouse model (Wang, 2005) and the Fgfr2cC342Y/+ Crouzon syndrome mouse model that carries a mutation common to both Crouzon and Pfeiffer syndromes (Eswarakumar et al., 2004; Figure 1). Here, FGFR2 is linked to Crouzon syndrome.