Identification of a mutation in the WISP3 gene in three unrelated families with progressive pseudorheumatoid dysplasia.

Progressive pseudorheumatoid dysplasia (PPD) is a rare autosomal recessive genetic disease, which is caused by the functional loss or abnormality of Wntl-inducible signaling pathway protein 3 [WISP3 protein (also termed CCN6, OMIM #603400)]. WISP3 is a member of the cysteine-rich 61/connective tissue growth factor/nephroblastoma overexpressed protein family. Mutations in WISP3 may result in continuous degeneration and loss of articular cartilage. The present study collected clinical data from three patients with PPD from three unrelated families, and WISP3 mutations were detected by polymerase chain reaction and direct sequencing. Overall, five mutations were identified, which consisted of two missense mutations, two nonsense mutations and one duplication mutation, which spanned exons 2, 4 and 5 of WISP3. In family 1, a compound heterozygosity mutation of WISP3 was detected, and the proband was shown to carry a novel missense mutation: c.667T>G (p.Cys223Gly) and a nonsense mutation: c.857C>G (p.Ser286*). The other three mutations: c.342T>G (p.Cys114Trp), c.136C>T (p.Gln46*) and c.866dupA (p.Ser290Glufs*13) had previously been identified. Overall, the three patients had similar clinical phenotypes, and no specific correlation between genotype and phenotype was detected. The results of the present study expand the WISP3 mutation spectrum that is associated with PPD and aid in further elucidating the function of WISP3.