Association of tumour necrosis factor-alpha G/A -238 and G/A -308 single nucleotide polymorphisms with juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is a heterogeneous autoimmune disorder of unknown origin. As proinflammatory cytokines are known to contribute towards the pathogenesis of JIA, this case-control study was performed to examine the associations of certain single nucleotide polymorphisms (SNPs) of tumour necrosis factor-α (TNF-α) gene. Fifty-three patients with JIA participated in this study as patients group and compared with 137 healthy unrelated controls. Genotyping was performed for TNF-α gene at positions -308 and -238, using polymerase chain reaction with sequence-specific primers method. Results of the analysed data revealed a significant positive association for TNF-α gene at positions -308 and -238 for A allele in patients group compared with controls (P < 0.01). At the genotypic level, the frequency of TNF-α gene at positions -308 and -238 for GG genotype was discovered to be higher in the patients with JIA compared to the healthy controls (P < 0.01), while GA genotype at the same positions was observed to be less frequent in the case group than the controls (P < 0.01). At the haplotypic level, a significant positive association for TNF-α GG haplotype (positions -308, -238) together with a notable negative association for TNF-α AG and GA haplotypes at the same positions were detected in the patients group in comparison with the healthy individuals (P < 0.01). Cytokine gene polymorphisms might affect the development of JIA. Particular TNF-α gene variants could render individuals more susceptible to JIA..