Peptidylarginine deiminase type 4 and methyl-CpG binding domain 4 polymorphisms in Chinese patients with rheumatoid arthritis.

OBJECTIVE:Peptidylarginine deiminase type 4 and methyl-CpG binding domain 4 (MBD4) are closely related with rheumatoid arthritis (RA). We hypothesized that and MBD4 polymorphisms may contribute to RA susceptibility. METHODS:We studied duanyu1563I4 rs2240340 G/A, duanyu1563I4 rs874881 C/G, MBD4 rs140693 G/A, and MBD4 rs2005618 T/C gene polymorphisms in 329 patients with RA and 697 controls in a Chinese population. Genotyping was done using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). RESULTS:When the duanyu1563I4 rs2240340 GG homozygote genotype was used as the reference group, the AA genotype was associated with a significantly increased risk of RA. In the recessive model, when duanyu1563I4 rs2240340 GG/GA genotypes were used as the reference group, the AA homozygote genotype was associated with a significant increased susceptibility to RA. duanyu1563I4 rs874881 C/G was in complete linkage disequilibrium with duanyu1563I4 rs2240340 G/A. MBD4 rs140693 G/A and MBD4 rs2005618 T/C polymorphisms were not associated with the risk of RA. In stratification analyses, a significantly increased risk for RA associated with the duanyu1563I4 rs2240340 AA genotype was evident among older patients and patients who were anticitrullinated protein antibody (ACPA)-positive compared with the duanyu1563I4 rs2240340 GG/GA genotype. CONCLUSION:These findings suggest that the functional single-nucleotide polymorphism duanyu1563I4 rs2240340 G/A variant allele is associated with RA development, especially among older patients and ACPA-positive patients. However, our results were obtained from a moderate-sized sample, and therefore this is a preliminary conclusion. Validation by a larger study from a more diverse ethnic population is needed to confirm these findings.

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