Idiopathic male infertility and polymorphisms in the DNA methyltransferase genes involved in epigenetic marking.

The purpose of this study was to investigate the association between male infertility and single-nucleotide polymorphisms (SNPs) of DNA methyltransferases (DNMT) genes (DNMT3B: rs2424909, DNMT1: rs4804490, DNMT3A: rs1550117 and DNMT3L: rs7354779). Eight hundred and thirty three idiopathic infertile males and four hundred and ten fertile controls from the hospitals affiliated to Nanjing Medical University between 2010 and 2012 were recruited in the study. We demonstrated a significantly increased risk of idiopathic infertility with abnormal semen parameters in association with the heterozygous genotype of variant rs4804490. Moreover, the AA genotype of variant rs4804490 was associated with significantly decreased risk for male infertility with abnormal semen parameters. A decreased risk of idiopathic infertility with abnormal semen parameters was associated with the homozygous genotype of variant rs2424909. These results suggested that variants in different DNMT genes have different relationships with idiopathic male infertility, and Chinese men carrying these variants have an increased or decreased risk of abnormal semen parameters.