Polymorphisms in folate-metabolizing genes and risk of idiopathic male infertility: a study on a Russian population and a meta-analysis

Objective To investigate the association of polymorphisms in the folate-metabolizing genes with idiopathic male infertility in a Russian population and to perform a meta-analysis. Design A case-control study. Setting Research laboratory. Patient(s) 275 men with idiopathic male infertility and a population sample of 349 men. Intervention(s) Determining the genotypes of polymorphisms MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G, SHMT1 C1420T, MTHFD1 G1958A, and CBS 844ins68. Main Outcome Measure(s) Semen analyses performed according to the World Health Organization guidelines (WHO, 1999) and Kruger strict morphology test. Result(s) None of the polymorphisms were significantly associated with idiopathic male infertility after the implementation of Bonferroni correction for multiple testing, although the MTHFD1 G1958A and MTR A2756G polymorphisms showed an association before the Bonferroni correction. Meta-analysis revealed an association by use of fixed-effects model of MTHFR C677T with the risk of azoospermia. Conclusion(s) These findings suggest that polymorphisms in folate-metabolizing genes could be involved in the etiology of male infertility. Additional studies performed on larger groups are necessary to investigate the possible associations.