Non-linear association between androgen receptor CAG repeat length and risk of male subfertility - a meta-analysis.

Summary The CAG repeat in the androgen receptor (AR) has been widely studied in association with male infertility, but the results are conflicting. In a recent meta-analysis, infertile men had 23 and analysed in a binary logistic regression model. Men with CAG 23 had 20% increased odds ratio of infertility compared with carriers of the median lengths [for CAG 23: p = 0.02, 95% CI: 1.03-1.44]. These results show that an alternative model to a linear one for the genotype-phenotype association in relation to AR CAG repeats is likely, as lengths close to the median confine lowest risk of infertility