CAG polymorphism of the Androgen Receptor gene and semen parameters in pathozoospermic patients with and without Y chromosome microdeletions, and in normozoospermic men

Abstract

Introduction. The effect of polymorphic variants of the androgen receptor gene (AR) on spermatogenesis and semen parameters in men with different genotypes for other loci has not been sufficiently studied.The aim of this work was to study the effect of the (CAG)n polymorphism of the AR gene on semen parameters in men with impaired fertility, with and without partial deletions of the AZFс region from the Y chromosome.Materials and methods. The study included 988 unrelated Russian patients with pathozoospermia, including 591 patients without Y chromosome microdeletions and 397 patients with partial deletions of the AZFc region of the Y chromosome. The control group consisted of 131 normozoospermic men. All men who participated in the study underwent semen analysis and genetic testing. Genomic DNA was isolated from peripheral venous blood lymphocytes and ejaculate. The analysis of the polymorphism of (GAG)n repeat in exon 1 of the AR gene was performed using a polymerase chain reaction by the amplified fragment length polymorphism method.Results. Three groups were studied: patients with pathozoospermia with (n = 32) and without (n = 541) Y chromosome microdeletions, and normozoospermic men (control, n = 131). The median and quartiles of the number of CAG repeats in the groups were 22 and 20-25, respectively. According to the number of trinucleotide repeats of the AR gene, all patients were divided into subgroups: carriers of short ((GAG)n ≤18), medium ((GAG)n = 19-25) and long ((GAG)n ≥26) alleles. Medium alleles prevailed in all groups; in men without AZFc deletions and with microdeletions, their frequency was 79.3 and 81.4 %, respectively, in controls - 81.7 %.Conclusion. No correlation was found in examined cohort for semen parameters (sperm concentration and total number, number of live, progressively motile and morphologically normal spermatozoa) from the number of trinucleotide repeats. However, a statistically significant difference (p ≤0.045; FDR correction) was found in concentration and total number, number of live, progressively motile and morphologically normal spermatozoa when comparing men with nomrozoospermia (control) with patients with pathozoospermia with and without partial AZFc deletions in subgroups of carriers of short, medium and long alleles.

Keywords

• androgen receptor
• male infertility
• pathozoospermia
• spermatogenesis
• trinucleotide repeats
• male fertility