After merging the Danish and North American cohorts and adjusting the model for the origin of the cohorts, we found that the minor allele (T) of rs11203367 in PADI4 (tag-SNP for a haplotype containing Gly55Ser, Val82Ala, and Gly112Ala) associated with anti-CCP-positive RA with an OR of 1.22. Here, PADI4 is linked to rheumatoid arthritis.