PADI4 polymorphisms and related haplotype in rheumatoid arthritis patients

Objective: To investigate whether peptidyl arginine deiminase type IV gene (PADI4) polymorphisms contribute to rheumatoid arthritis (RA) susceptibility in Egyptians, whether they influence disease severity and activity, and whether they affect anti-mutated citrullinated vimentin antibodies (anti-MCV) level. Methods: Three PADI4 single nucleotide polymorphisms (SNPs) (PADI4-92, PADI4-96, and PADI4-102) were screened in 275 RA patients and 275 unaffected controls by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method. Serum anti-MCV levels were measured by enzyme-linked immunosorbent assay (ELISA). Results: There were significant associations between RA susceptibility with the minor alleles of PADI4-92 and PADI4-102 {[}odds ratio (OD) and 95\% confidence interval (CI) for the minor alleles of PADI4-92 and PADI4-102: 1.48 (1.17-1.88) and 2.05 (1.61-2.61) respectively] but not with PADI4-96 {[}OD and 95\% CI for the C allele: 1.09 (0.86-1.39)]. PADI4 haplotypes 2 (GCC) and 3 (GCT) were also associated with RA susceptibility while PADI4 haplotypes 1 (CTC) may be protective against developing of this disease. A significant association was detected between PADI4 haplotypes and RA severity. Conclusions: The PADI4 SNPs and haplotypes were associated with RA susceptibility, although no relation was observed between the PADI4 haplotypes and anti-MCV levels. (C) 2011 Societe francaise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.