Altered FGF signalling in congenital craniofacial and skeletal disorders.

The fibroblast growth factor (FGF) signalling pathway has been the focus of intense genetic and functional research for several decades. The emerging data implicate FGF signalling in diverse regulatory processes, both in the developing embryo as well as in the adult organism. Alterations in this tightly regulated pathway can lead to a number of pathological conditions, ranging from well-recognized congenital disorders to cancer. In order to mediate their cellular processes, FGFs signal through a subfamily of tyrosine kinase receptors, called FGF receptors (FGFRs). In humans, four FGFRs are described, and, to date, mutations in FGFR1, FGFR2, and FGFR3 have been shown to underlie human developmental disorders. FGFs/FGFRs are known to be key players in both endochondral and intramembranous bone development. In this review, we focus on the major developmental craniofacial and skeletal disorders which result from altered FGF signalling.