Plays an important role in the regulation of embryonic development and as signaling molecule in the induction and patterning of the embryonic brain. Required for normal brain development. Interacts with FGFR3 and FGFR4. Expressed in embryonic brain, mostly in the isthmus cerebellar neuroepithelium and septum neuroepithelium, and in all adult tissues. Expressed at high level in the brain embryo at E14.5. Expressed at lower level in the brain embryo at E10.5 and E19.5. Belongs to the heparin-binding growth factors family.