CAG Repeat Polymorphism of the Mitochondrial DNA Polymerase Gamma Gene in Macedonian Infertile and Fertile Men

The catalytic subunit of human mitochondrial DNA polymerase gamma (POLG) is encoded by the POLG gene, located on chromosome 15q24 and includes a polymorphic CAG repeat. Analysis of POLG genotypes in some populations has identified an association between the absence of the 10 CAG repeat allele and male infertility and suggested that POLG gene polymorphism should be considered as a possible contributing factor in cases with idiopathic subfertility with normal spermiograms. We undertook to assess whether different POLG CAG alleles are associated with impaired spermatogenesis and infertility/subfertility in Macedonian men. We studied 225 infertile/subfertile men (74 with azoospermia, 56 with severe oligozoospermia, 27 with mild oligozoospermia, 39 with unexplained infertility and normal sperm counts, and 29 with known causes of infertility) and a control group of 123 proven fathers, by fluorescent polymerase chain reaction (PCR) andanalysis on an ABI PRISM™ 310 Genetic Analyzer. The most frequently observed POLG allele was the common one of 10 CAG repeats with a frequency of 87.6% in the infertile/subfertile group and 86.6% in the control group. The homozygous mutant POLG genotype (not10/not10) was found in both groups, 1.6% in the infertile/subfertile patients and 1.8% in the controls. In conclusion, our study showed no association between polymorphism of the POLG gene and infertility in Macedonian men.