The sole mutation responsible for Muenke syndrome is c.749C>G/p.Pro250Arg. Features of Muenke syndrome are variable ranging from no clinically apparent abnormalities to a complex combination of findings. The main characteristic is unilateral or bilateral coronal craniosynostosis or megalencephaly without craniosynostosis. Other features may include midface hypoplasia, hypertelorism, carpal-tarsal fusion, brachydactyly, sensorineural hearing loss, and osteochondroma. Intellect ranges from normal to mild intellectual disability. This laboratory performs targeted mutation analysis for the c.749C>G/p.Pro250Arg mutation in the FGFR3 gene.