We previously reported that overexpression of CNP in chondrocytes counteracts dwarfism of an achondroplasia model mouse with activated FGFR-3 in the cartilage, and exhibited that inhibition of the MAPK/ERK pathway is one of the mechanism of an antagonistic effect of CNP to FGFR-3 signaling [5]. Here, CNP is linked to achondroplasia.