title: CAG-repeat polymorphisms in the polymerase γ gene and male infertility: a meta-analysis.
abstract: CAG-repeat in the polymerase γ (POLG) gene encoding polymerase γ for mitochondria is important to spermatogenesis. Compared with a few researchers who raised alteration of CAG-repeat-affected male reproductive ability, others did not find the association between CAG-repeat polymorphisms and male infertility. Therefore, a comprehensive meta-analysis is necessary to determine the association; 13 case-control studies were screened out using keywords search. From these studies, characteristics were extracted for conducting meta-analysis. Odds ratio (OR) and 95% confidence interval (CI) were used to describe the results; the results indicated that CAG-repeat allele was not a risk factor to male infertility (pooled OR = 1.03, 95% CI: 0.79-1.34, P = 0.828). Four different genetic comparisons also demonstrated a negative result: heterozygote comparison (not 10/10 versus 10/10. Pooled OR = 0.99, 95% CI: 0.77-1.27, P = 0.948), homozygote comparison (not 10/not 10 versus 10/10. Pooled OR = 1.08, 95% CI: 0.56-2.06, P = 0.816), the recessive genetic comparison (not 10/not 10 versus not 10/10 + 10/10. Pooled OR = 1.07, 95% CI: 0.58-1.95, P = 0.829) and the dominant genetic comparison (not 10/not 10 + not 10/10 versus 10/10. Pooled OR = 0.97, 95% CI: 0.72-1.29, P = 0.804); based on current researches, this meta-analysis demonstrated no apparent association between POLG-CAG-repeat and male infertility. Similarly, CAG-repeat was not a sensitive site to male infertility.
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: W
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: M
authors.initials: M
authors.lastname: Ni
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: P
authors.initials: P
authors.lastname: Zhu
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Reproduction and Genetics, Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China. xiaxynju@163.com.
authors.forename: X
authors.initials: X
authors.lastname: Xia
mesh_terms: D016022:Case-Control Studies; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D056726:Genetic Association Studies; D006801:Humans; D007248:Infertility, Male / Q000201:enzymology* / Q000235:genetics*; D008297:Male; D018598:Minisatellite Repeats; D008957:Models, Genetic; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D018911:Trinucleotide Repeats
chemical_list: D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C413027:POLG protein, human
keywords: Case-control study; POLG-CAG polymorphisms; male infertility; meta-analysis