CCN6 and polyarticular arthritis: One analysis of WISP3 SNPs in blood samples obtained from two independent cohorts of patients with polyarticular-course JIA (≥5 joints involved) that included diagnoses of extended oligoarthritis, RF-negative polyarthritis and RF-positive polyarthritis, found replication of a positive association with an SNP within the first intron of the WISP3 gene (WISP3*G84A) [23].