GDF5 and acromesomelic dysplasia 2B: The CDMP1 has a murine homologue growth and differentiation factor-5 (Gdf5) and its absence leads to brachypodism in mice [4] and a number of skeletal malformation syndrome in humans including brachydactyly type A2 [5,6], brachydactyly type C (BDC) [7-10], fibular hypoplasia and complex brachydactyly (Du Pan syndrome) [11], Grebe-type chondrodysplasia [2,12-14], Hunter-Thompson type acromesomelic dysplasia [15], angel-shaped phalangeal dysplasia [16], multiple synostoses syndrome type 1 [17] and proximal symphalangism (SYM1) [5,10].