AS expression profile was confirmed through real-time PCR of a selected set of genes using RNAs from AS and control cells as well as from control cells treated with high FGF2 concentration, and through the analysis of genes involved in FGF-FGFR signaling.
The crystal structure, of Pro252Arg FGFR1c in complex with FGF2, demonstrates that the enhanced ligand binding is due to an additional set of receptor-ligand hydrogen bonds, similar to those gain-of-function interactions that occur in the Apert syndromePro253Arg FGFR2c-FGF2 crystal structure.
Expression of FGFR2, however, is restricted to domains of advanced osseous differentiation in both Apert syndrome- and Pfeiffer syndrome-affected cranial skeletogenesis in the presence of fibroblast growth factor (FGF)2, but not in the presence of FGF4 or FGF7.