title: CAG repeat length variation in the polymerase gamma (POLG) gene: effect on semen quality.
abstract: Several case-control studies have investigated the effect of CAG repeat length variation in the POLG gene on male fertility and semen quality. Some described an association between the homozygous not10 CAG-repeat genotype and male subfertility and/or reduced semen quality, whereas others did not. The aim of our study was to investigate whether the not10/not10 variant is associated with spermatogenic failure. By direct sequencing methods, we determined the CAG repeat length of POLG in a cohort of 700 consecutive included men with variable degrees of spermatogenesis to investigate its effect on semen quality. The frequency of the not10/not10 variant in our cohort was 4.7%. There were no differences in semen quality between groups with various POLG genotypes. There was a significant difference in frequency of the three CAG-repeat genotypes between ethnic subgroups. In conclusion, the not10/not10 POLG variant is not associated with clinically significant decreases in semen quality, but its frequency is dependent on ethnic background.
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Academic Medical Center, Meibergdreef 9, H4-205, 1105 AZ Amsterdam, The Netherlands. g.h.westerveld@amc.uva.nl
authors.forename: G H
authors.initials: GH
authors.lastname: Westerveld
authors.forename: L
authors.initials: L
authors.lastname: Kaaij-Visser
authors.forename: M
authors.initials: M
authors.lastname: Tanck
authors.forename: F
authors.initials: F
authors.lastname: van der Veen
authors.forename: S
authors.initials: S
authors.lastname: Repping
mesh_terms: D000328:Adult; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D012661:Semen / Q000378:metabolism*; D018911:Trinucleotide Repeats / Q000235:genetics*
chemical_list: D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase