CCN6 and progressive pseudorheumatoid arthropathy of childhood: Liao et al. have predicted that the C-terminal peptide is located in the opposite direction in the Ser334Pro mutant CCN6 protein with another c.840delT in the compound heterozygous mutation, which changes the 3D-conformational structure of the mutant protein, and therefore concluded that the coexistence of a c.1000T>C substitution is necessary for the clinical onset of PPD [9].