Objective: A novel association with a 100-kb region on chromosome 9 that contains the tumor necrosis factor receptor-associated factor 1 (TRAF1) and C5 genes has been observed in some autoimmune rheumatic diseases, in particular in rheumatoid arthritis. We analyzed the influence of 2 single-nucleotide polymorphisms (SNP) from the TRAF1/C5 region in susceptibility to giant cell arteritis (GCA).
Methods: We assessed 220 patients with biopsy-proven GCA and 410 matched controls. DNA from patients and controls was obtained from peripheral blood. Samples were genotyped for the rs10818488 and rs2900180 TRAF1/C5 gene polymorphisms by polymerase chain reaction, using a predesigned TaqMan allele discrimination assay.
Results: A genotyping rate of 95% was achieved in this series of GCA. No significant differences in the genotype distribution between GCA patients and controls were found for the 2 SNP. GCA patients exhibited a reduced frequency of TRAF1/C5 AA homozygosity (7.6%) compared to controls (12.7%) but the difference was only marginally significant (OR 0.58, 95% CI 0.30-1.11, p = 0.07). The frequency of minor allele T of TRAF1/C5 rs2900180 was also slightly reduced in patients (24.3%) compared to controls (27.8%) (p = 0.19). No significant differences were observed when patients were stratified according to the presence of specific clinical disease features.
Conclusion: Our results showed no influence of rs10818488 and rs2900180 TRAF1/C5 gene polymorphisms in susceptibility to and clinical expression of GCA.