Association Study of PTPN22 (rs2476601) and PADI4 (rs2240340) Polymorphisms with Rheumatoid Arthritis in Algerian Population

An association between protein tyrosine phosphatase 22 (PTPN22) and Peptidylarginine deiminase 4 (PADI4) genes with rheumatoid arthritis (RA) has been demonstrated in several populations. The present study investigated whether PTPN22 and PADI4 genes polymorphisms were involved in the genetic predisposition to RA in the Algerian patients. Materials and methods: The PADI4_94 (rs2240340) and the PTPN22 (rs2476601) Single Nucleotide Polymorphisms (SNPs) were genotyped in 300 RA patients and 306 healthy controls by real time polymerase chain reaction method (TaqMan Assays). The relationships between Anti-Citrullinated Peptide Antibody (ACPA) positivity, Rheumatoid Factor (RF) positivity and genotypes were statistically analyzed. Results: There was no significant association between the PTPN22, PADI4 SNP and RA susceptibility in our population (p>0.05). No association with ACPA profile with either PTPN22 or PADI4 was detected (p>0.05). However, our results showed a strong association of PTPN22 minor T allele with RF positive disease (OR=8.53 (95% CI 1.34-354.9), p=0.013); also, a significant association was shown between CT genotype of PTPN22 SNP and RF positive RA (OR=8.01 (95% CI 1.22-336.5), p=0.018). Conclusion: Our findings indicated that PTPN22 and PADI4 polymorphisms were unlikely to play an important role in the susceptibility to RA in Algerian population but PTPN22 polymorphism T allele may predispose individuals to RF positive RA.