TNF-α-308G/A polymorphism associated with TNF-α protein expression in patients with diabetic nephropathy.

AIMS This study was to clarify the regulated effects of TNF-α -308G/A polymorphism on TNF-α and investigate the relationship of -308G/A polymorphisms with diabetic nephropathy (DN) susceptibility. METHODS 86 DN patients and 94 healthy individuals were enrolled in our study. Polymerase chain reaction-sequence specific primer (PCR-SSP) detection technology was used to testify single nucleotide polymorphism (SNP) of TNF-α gene. Enzyme-linked immunosorbent assay (ELISA) was used to measure the content of TNF-α protein. Odds ratio (OR) with 95% CI were used to evaluate the association of TNF-α -308G/A polymorphism and DN susceptibility. RESULTS The level of TNF-α protein was much higher in DN patients compared to that of controls (P<0.05). For TNF-α -308G/A, G/A genotype could increase the risk for DN (OR=2.15, 95% CI=1.08-4.30). Moreover, a allele frequency was found higher in cases compared with controls, which suggested that A allele served as an genetic-susceptibility factor for DN (OR=1.89, 95% CI=1.10-3.26). Further analysis indicated that level of TNF-α for individuals with mutant genotype (GA and AA) were higher than that of individuals with wild genotype (P<0.05). However, AA genotype showed no effects on DN susceptibility (OR=2.08, 95% CI=0.56-7.33). CONCLUSION TNF-α-308G/A polymorphism was associated with expression level of TNF-α and served as an genetic-susceptibility factor for DN.