Analysis of polymorphisms in the SRD5A2 gene and semen parameters in Estonian men.

Spermatogenesis is an androgen-dependent process and polymorphisms in genes encoding androgen-metabolizing enzymes may be associated with impaired male fertility. The enzyme steroid 5α-reductase converts testosterone into dihydrotestosterone. We analyzed genotype frequencies of 5 single-nucleotide polymorphisms (SNPs 1-5) (rs632148, rs523349, rs2300701, rs2268797, and rs12470143) in the steroid 5α-reductase type 2 gene (SRD5A2) in 132 azoospermic or oligozoospermic and 211 normozoospermic men. We found no association between investigated genotypes and the occurrence of male infertility. Linear regression analysis revealed a significant correlation between certain alleles of SNP1 and SNP5 and testicular volume among control men. Normozoospermic men carrying the minor allele of all but SNP5 polymorphism exhibited a significantly higher proportion of progressively motile spermatozoa, compared with major homozygotes. However, SRD5A2 genotypes did not influence sperm concentration, serum testosterone, or follicle-stimulating hormone levels in controls. Our results suggest that polymorphisms examined in SRD5A2 exhibit no adverse effect on semen parameters in Estonian men.