The most detailed studies have been undertaken for two different mutations of FGFR2 (c.755C>G encoding p.Ser252Trp and c.758C>G encoding p.Pro253Arg, both causing Apert syndrome) and a mutation in RET (c.2943T>C, encoding p.Met918Thr and causing multiple endocrine neoplasia type 2B [Men2B]) [20], [21], [22]. Here, RET is linked to Apert syndrome.