Preliminary study showing no association between G238A (rs361525) tumor necrosis factor-α (TNF-α) gene polymorphism and its serum level, hormonal and biochemical aspects of polycystic ovary syndrome.

BACKGROUND

Polycystic ovary syndrome (PCOS) is the main cause of female infertility. Interactions among genetic, biochemical, and immunological factors can affect the pathogenesis of PCOS. As a proinflammatory cytokine, tumor necrosis factor-α (TNF-α) plays an important role in this regard. The present study aimed to evaluate the association of the rs361525 gene single-nucleotide polymorphism (SNP) and TNF-α serum levels with the hormonal and biochemical characteristics of PCOS in Iranian individuals.

METHODS

The SNP rs361525 in the TNF-α gene was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in a total of 111 PCOS patients and 105 healthy females. Serum levels of TNF-α, lipid and hormone profiles, and biochemical factors were measured using enzyme-linked immunosorbent assay (ELISA) and calorimetric methods, as appropriate.

RESULTS

The TNF-α serum level was higher in women with PCOS compared with the control group (p <  0.0001), and it was significantly correlated with the homeostasis model assessment (HOMA) factor (r = 0.138, p <  0.05). No significant differences were found in the genotype and allelic frequencies between the two groups (p >  0.05). Higher levels and significant differences were found for the HOMA factor, luteinizing hormone/follicle-stimulating hormone (LH/FSH), testosterone, and body mass index (BMI) in the PCOS group compared with the control group (p <  0.0001). High LH/FSH ratios (odds ratio [OR] = 1.98, 95% confidence interval [CI] = 1.20-3.28, p <  0.01), and high HOMA factor (OR = 5.04, 95% CI = 2.82-9.01, p <  0.001) were significantly associated with an increased risk of PCOS.

CONCLUSIONS

Despite the lack of significant difference between rs361525 polymorphism of the TNF-α gene and PCOS, the serum level of TNF-α was increased in PCOS patients and positively correlated with the HOMA factor. Elevation of the LH/FSH ratio and HOMA for insulin resistance (HOMA-IR) increased the risk of PCOS. Therefore, TNF-α could indirectly contribute to PCOS progression.