MLH1 and Infertility: On the basis of analysis of 480 controls and 524 infertility patients with azoospermia or oligozoospermia, we observed that one intronic SNP in MLH1 (rs4647269) and two non-synonymous SNPs in PMS2 (rs1059060, Ser775Asn) and MSH5 (rs2075789, Pro29Ser) were associated with increased susceptibility to poor sperm production.