IRAK1 rs3027898 C/A polymorphism is associated with risk of rheumatoid arthritis.

IRAK1 and miR-499 play an important role in the etiology of rheumatoid arthritis. Few studies to date have focused on the influence of the IRAK1 rs3027898 C/A and hsa-mir-499 rs3746444 T/C polymorphisms in the susceptibility of the Chinese population to rheumatoid arthritis. We hypothesized that these polymorphisms may contribute to rheumatoid arthritis susceptibility. We studied IRAK1 rs3027898 C/A and hsa-mir-499 rs3746444 T/C gene polymorphisms in 214 rheumatoid arthritis cases and 478 controls in a Chinese population. Genotyping was performed by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). When the IRAK1 rs3027898 CC homozygote genotype was used as the reference group, the AA genotype was associated with significantly increased risk of rheumatoid arthritis (odds ratio (OR) = 1.91, 95 % confidence interval (CI) = 1.12-3.26, p = 0.017). A significantly increased risk of RA associated with the IRAK1 rs3027898 AA genotype was more evident among females, younger patients, CRP negative patients and both anti-CCP positive and negative patients compared with the IRAK1 rs3027898 CC/CA genotypes. The hsa-mir-499 rs3746444 T/C single nucleotide polymorphism (SNP) was not significantly associated with the risk for rheumatoid arthritis. Our findings suggest that the functional SNP IRAK1 rs3027898 C/A variant allele is associated with the development of rheumatoid arthritis. However, the hsa-mir-499 rs3746444 T/C polymorphism may not be associated with susceptibility to rheumatoid arthritis.