More than half (N = 156) of the 277 linear distance pairs that were found to be significantly different in the comparison of Fgfr2+/S252W Apert syndrome mice and Fgfr2cC342Y/+ Crouzon syndrome mice were also found to be significantly different in our comparison of the unaffected littermates of the two models. This evidence concerns the gene FGFR2 and Crouzon disease.