TNF promoter -308 A/G and -238 A/G polymorphisms and juvenile idiopathic arthritis: a meta-analysis

The aim of this study was to determine whether the tumor necrosis factor (TNF) promoter polymorphisms confer susceptibility to juvenile idiopathic arthritis (JIA). A meta-analysis was conducted on the A allele of the TNF -308 A/G and -238 A/G polymorphisms. The nine comparison studies including 1,132 JIA patients and 1,663 controls were included in the meta-analysis and consisted of 7 European, 1 Mexican, and 1 Turkish population. No association was found between JIA and the TNF -308 A allele and the TNF -238 A allele (odds ratio [OR] = 1.211, 95 % confidence interval [CI] = 0.917-1.598, P = 0.177; OR = 1.135, 95 % CI = 0.603-1.861, P = 0.615, respectively). Stratification by ethnicity did not show the association of the TNF -308 and -238 polymorphisms with JIA in Europeans. Mexicans were found to have lower prevalences of A alleles (2.9, 4.1 %) of the TNF -308 A/G and -238 A/G polymorphisms than any other population studied, and the Turkish population the highest (31.2, 26.9 %). This meta-analysis shows no association between the A alleles of the TNF -308 A/G or -238 A/G polymorphisms and JIA in Europeans, but that the prevalences of these alleles are ethnicity dependent.