Objective: To assess the association of male infertility with CAG repeat polymorphism of the androgen receptor (AR) gene by meta-analysis.
Methods: We identified the case-control studies on the relationship of male infertility with CAG repeats of the AR gene by searching Medline/PubMed and CBM databases, and conducted meta-analysis on the data obtained with the RevMan 4.2 software.
Results: Thirty-two eligible articles were selected in this study, including 3,153 idiopathic infertile men and 2,314 controls. The combined data statistics showed that all the infertile men had a significantly higher mean of CAG repeats than the controls (SMD = 0.27, 95% CI: 0.17-0.37, P < 0.01). The specific SMD between the infertile patients and controls was 0.29, 95% CI: 0.08-0.50 for the azoospermic men, 0.27, 95% CI: 0.13-0.41 for the moderate oligozoospermic men, and 0.18, 95% CI: 0.02-0.33 for the severe oligozoospermic cases. The results of sensitivity analyses were consistent with those mentioned above.
Conclusion: The increased length of CAG repeats in the AR gene may be correlated with the risk of the impairment of spermatogenesis.