PADI4 polymorphisms and rheumatoid arthritis susceptibility: a meta-analysis

We conducted a comprehensive meta-analysis with all available data on the association of allele and genotype of peptidylarginine deiminases 4 (PADI4) polymorphisms with RA overall and in each ethnic population to explore whether the PADI4 polymorphisms confer susceptibility to RA. Nine comparisons, three Asians and six Europeans, from eight studies were included in this meta-analysis. Overall meta-analysis shows a significant association of PADI4_94, 104 and 90 with RA (OR = 1.20, 1.17, 1.35, P = 0.001, <0.0001, 0.006, respectively). There was a significant association with all of the PADI4 polymorphisms with RA in people of Asian descent. However, there was no significant association of PADI4 polymorphisms with RA in people of European descent, except for PADI_94. The presence of 2/2 genotype of the PADI4 significantly increased the risk for RA in European populations (OR = 2.10, 95% CI, 1.66–2.66, P < 0.0001) without between-study heterogeneity (I ² = 44.3, P = 0.15). In conclusion, this meta-analysis demonstrates that the PADI4 polymorphisms may represent a significant risk factor for RA in Asians and Europeans and may play a larger role in susceptibility to RA in Asian than in European populations. Further studies are needed to see if the PADI4 gene confers a risk of RA in other ethnic groups.