Fibroblast growth factor receptor mutations cause some of the main short-limb skeletal dysplasias and craniosynostosis syndromes, including achondroplasia, hypochondroplasia, thanatophoric dysplasia, Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, and Jackson-Weiss syndrome. Much work remains to be done in unraveling the pathogenesis of these phenotypes.