Role of the interleukin-6 -174 G>C gene polymorphism in retinal artery occlusion.

BACKGROUND AND PURPOSE Proinflammatory cytokines including interleukin-6 (IL-6) are supposed to play a pivotal role in the development of atherosclerosis. A common polymorphism in the promoter of the IL-6 gene (IL-6 -174G>C) affects plasma IL-6 concentrations and has been suggested as a risk factor for cardiovascular disease. The aim of the present case-control study was to investigate the role of this polymorphism for retinal artery occlusion (RAO). METHODS One hundred eighty-two patients with RAO and 307 control subjects were genotyped for the IL-6 -174G>C polymorphism. Genotypes were determined by fluorogenic exonuclease (TaqMan) assay. RESULTS The prevalence of the CC genotype was significantly lower in patients with RAO than in control subjects (10.4% versus 19.9%; P=0.006). Homozygosity for the C allele was associated with an odds ratio of 0.50 (95% CI, 0.28 to 0.89) for RAO. CONCLUSIONS The CC genotype of the IL-6 -174G>C polymorphism may be associated with a protective effect against RAO.