Tumor necrosis factor alpha-308 polymorphism is associated with rheumatoid arthritis in Han population of Eastern China

The aim of this study was to investigate the association of single nucleotide polymorphisms (SNPs) in tumor necrosis factor alpha (TNF alpha) promoter with rheumatoid arthritis (RA) in Chinese Han population. Six SNPs at positions -238, -244, -308, -376, -857, -863 within TNF alpha promoter were genotyped in 367 unrelated RA patients and 271 healthy controls, using direct DNA sequencing method. Allelic, genotypic, and haplotypic associations of these SNPs with RA were examined. The frequencies of TNF alpha -308A allele and the haplotype GACC (in order of -238, -308, -857, -863) were significantly lower in RA patients when compared with healthy controls (P = 0.0046, P = 0.0045, respectively) but TNF alpha -308 polymorphism was not related to the clinical manifestations of RA patients. These results implied that TNF alpha gene itself or a gene in linkage disequilibrium with it might be associated with RA in Han population of Eastern China.