Polypeptide growth factors are secreted signalling molecules that function as intercellular communicators. Detailed analyses of the expression and function of members of the fibroblast growth factor (FGF) family and their recepotors have demonstrated that the FGF signalling pathways play essential roles in regulating cellular proliferation, differentiation and tissue patterning during vertebrate embryogenesis. Recent studies on the molecular basis of human dysmorphic syndromes have revealed that aberrant FGF signalling during limb and skeletal development can lead to pathogenesis.