GDF-5 is expressed in long bones during embryonic development and postnatally in articular cartilage. Mutations in the GDF-5 gene have been implicated in Grebe Syndrome, which is characterized by short stature, extra digits, short and deformed extremities, and in Hunter-Thompson type dwarfism. The mature and functional form of GDF-5 is a homodimer of two 120 amino-acid polypeptide chain (monomers) linked by a single disulfide bond. Each GDF-5 monomer is expressed as the C-terminal part of a precursor polypeptide, which also contains a 27 amino-acid signal peptide and a 348 amino-acid propeptide. This precursor undergoes intracellular dimerization, and upon secretion it is processed by a furin-type protease. Recombinant murine GDF-5 is a 27.0 kDa homodimeric disulfide-linked protein consisting of two 120 amino acids.