GDNF, Glial cell-derived neurotrophic factor, is a protein that, in humans, is encoded by the GDNF gene. GDNF is a small protein that potently promotes the survival of many types of neurons. GDNF is a founding member of the GDNF family of ligands (GFL).The GDNF gene is mapped to human chromosome 5p13.1-p12 by fluorescence in situ hybridization (FISH). This gene encodes a highly conserved neurotrophic factor. The recombinant form of this protein was shown to promote the survival and differentiation of dopaminergic neurons in culture, and was able to prevent apoptosisof motor neurons induced by axotomy. The encoded protein is processed to a mature secreted form that exists as a homodimer. The mature form of the protein is a ligand for the product of the RET (rearranged during transfection) protooncogene.