Although the anterior body of the Fgfr2cC342Y/+ Crouzon/Pfeiffer syndrome mouse mandible showed a distinct morphology relative to their unaffected littermates, there was less difference in the anterior body of Fgfr2+/S252W and Fgfr2+/P253R Apert syndrome mice relative to their respective unaffected littermates (Fig. S2). Here, FGFR2 is linked to Apert syndrome.