Androgen receptor gene haplotype is associated with male infertility

The purpose of the current study was to evaluate the importance of androgen receptor (AR) gene haplotypes and polymorphic CAG/GGN microsatellites in the aetiology of male infertility. We genotyped six haplotype-tagging single nucleotide polymorphisms and CAG/GGN microsatellites of the AR gene in 112 infertile and 212 control Estonian men. A total of 13 AR haplotypes (HAP1-13) were identified, among which HAP4 was found to confer increased risk for male infertility (OR = 5.15, 95% CI = 1.75-15.15, p = 0.003). However, infertile patients and controls had similar lengths and distributions of both AR CAG (mean +/- SD number of repeats 21.1 +/- 2.5 vs. 21.2 +/- 2.3, respectively) and GGN (mean +/- SD number of repeats 22.5 +/- 1.5 vs. 22.4 +/- 1.9, respectively) repeats. In addition, HAP2 was associated with more CAG repeats (r = 1.17, p = 0.033) and HAP3 with fewer CAG repeats (r = -2.93, p < 0.001) than the major haplotype HAP1. HAP3 and HAP4 were associated with more GGN repeats (r = 1.35, p = 0.001 and r = 1.36, p = 0.002, respectively) than HAP1. In conclusion, our results implicated the AR-HAP4 gene haplotype in increased risk for male infertility, while no association was found between AR CAG/GGN microsatellites and impaired spermatogenesis.