Human FGF-18 is encoded by the FGF18 gene. By phylogenetic analysis and gene location analysis, FGF-18 is divided into FGF-8 subfamily which has three members FGF-8, FGF-17 and FGF-18. Using FGF knockout mice model, the numbers of this subfamily were testified that have crucial roles of in embryo development. FGF-18–/– mice have decreased expression of osteogenic markers and delayed long-bone ossification. FGF-18 has been shown in vitro that this protein is able to induce neurite outgrowth in PC12 cells. In addition, it also has significant roles in lung development and has an anabolic effect on cartilage formation.