The function of FGF4 (fibroblast growth factor 4, Ensembl gene identifier ENSG00000075388) is as follows. Plays an important role in the regulation of embryonic development, cell proliferation, and cell differentiation. Required for normal limb and cardiac valve development during embryogenesis. May play a role in embryonic molar tooth bud development via inducing the expression of MSX1, MSX2 and MSX1-mediated expression of SDC1 in dental mesenchyme cells (By similarity). {ECO:0000250|UniProtKB:P11403, ECO:0000269|PubMed:8663044}.