In ∼70% of cases, Apert syndrome (MIM #101200) is caused by a c.934C→G (Ser252Trp) mutation in the FGFR2 gene (MIM *176943.0010) and, in rare other cases, by a mutation in the next adjacent codon, c.937C→G (Pro253Arg [MIM *176943.0011]). No phenotypic features distinguishing the two genotypic forms were found.30 As cataloged in OMIM, the FGFR3, LMNA, and FGFR2 genes are also the sites of mutations causing, respectively, 9, 12, and 11 other phenotypically distinct disorders.