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.
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).
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.
The PADI4 SNPs and haplotypes were associated with RA susceptibility, although no relation was observed between the PADI4 haplotypes and anti-MCV levels.