A common interleukin-6 gene promoter polymorphism influences the clinical characteristics of women with polycystic ovary syndrome

Objective: To investigate the association of a common polymorphism of the interleukin-6 gene (IL6) promoter with the occurence and the clinical characteristics of polycystic ovary syndrome (PCOS). Design: Prospective, case-control study. Setting: Academic research institution. Patient(s): Sixty-two patients with PCOS and 94 healthy controls. Intervention(s): Peripheral venous puncture, ultrasonography, oral glucose tolerance test (OGTT), questionnaire. Main Outcome Measure(s): Genotype analysis with respect to the common - 174 G/C polymorphism of the IL6 gene promoter, analysis of testosterone (T), androstendione, and sex hormone binding globulin serum levels, and evaluation of the OGTT. Result(s): Allele frequencies among women with PCOS and controls were 62.9% and 64.4%, respectively, for the wild-type G allele, and 37.1% and 35.6%, respectively, for the mutant C allele. We ascertained a significant association between presence of at least one mutant C allele and the clinical characteristics of affected women: these women were more likely to present with a body mass index >27 kg/m(2), elevated total T serum levels, and a pathological OGTT result. Conclusion(s): A common polymorphism of the IL6 promoter, although not associated with the presence of PCOS, is associated with the clinical characteristics of women affected by this condition.