All the symptoms and signs found in the five probands were consistent with those from published studies (Cassa et al., 2016; Delague et al., 2005; Garcia Segarra et al., 2012; Luo et al., 2015; Rai et al., 2016), in which CCN6 was the pathogenic gene for PPD. This evidence concerns the gene CCN6 and progressive pseudorheumatoid arthropathy of childhood.