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Infertility is known to occur frequently worldwide, and the incidence is continuing to rise in China. It is known that semenogelin (SEMG) protein secreted by human seminal vesicles plays an important role in male reproductive system function. However, an association between alterations in SEMG gene functions and idiopathic male infertility occurrence in Chinese-Han population has not been examined. The aim of this study was thus to investigate the inherent relationship between SEMG gene alterations and idiopathic male infertility using a method of variant genotyping selection and semen quality analysis. A population of 484 males with clinically diagnosed idiopathic male infertility and 246 fertile controls were selected after signing consent forms. Results demonstrated a significantly increased frequency of idiopathic infertility with abnormal semen parameters such as semen volume, sperm concentration, sperm number per ejaculate, and sperm motility in variants carrying the rs2301366 TA genotype. Combined association analysis from target single-nucleotide polymorphisms (SNPs) was selected from the genotype database of unrelated Chinese-Han in Beijing individuals from the Hap Map. SNP array analysis in blood samples in each group was carried out by TaqMan Universal PCR Master Mix and TaqMan SNP Genotyping Assays. In addition, the interaction between SEMG SNPs and binding protein epididymal protease inhibitor (EPPIN) SNPs was determined. Our findings demonstrated that the presence of SEMG SNPs and EPPIN SNPs increased the frequency of idiopathic male infertility in Chinese-Han population. It is proposed that measurement of SEMG SNPs and EPPIN SNPs in carriers may thus be utilized to identify idiopathic male infertility. [ABSTRACT FROM AUTHOR]

Recent experimental animal studies suggested that the circadian locomotor output cycles kaput protein gene (CLOCK) has been reported to play a critical role in sperm function and male fertility. The aim of this study was to determine whether variants of the CLOCK gene are involved in idiopathic male infertility. The study included 478 idiopathic infertile men and 194 fertile controls who completed physical examinations. Each subject donated 5 ml of peripheral blood and a sample of semen in the ejaculate. An aliquot of each blood sample was used to separate the serum for the measurement of testosterone as well as follicular stimulating hormone (FSH) using the standard radioimmunoassay. The rest of the blood samples was used to extract the DNA for the assay of three tagging single-nucleotide polymorphisms of CLOCK gene, viz., rs1801260, rs3817444 and rs3749474, using the real-time fluorescence quantitative PCR. The ejaculate of each subject was used for semen analysis by computer-assisted semen analysis system. The results indicated: (a) the variant rs1801260 associated with normal semen parameters was linked to a significant increase in the risk of idiopathic infertility, (b) the variant rs3817444 associated with both normal and abnormal semen parameters also indicated an increased risk of idiopathic infertility, and (c) the variants rs3749474 associated with both normal and abnormal semen parameters, on the other hand, conferred no significant risk for male infertility. Furthermore, elevated serum testosterone and FSH levels were correlated with the three variants of CLOCK gene in idiopathic infertility. The findings demonstrate that the human subjects with variants of the CLOCK gene are associated with idiopathic male infertility and therefore may be applied as a risk factor of male infertility. [ABSTRACT FROM PUBLISHER]

Background: It has been identified that human epididymal protease inhibitor (EPPIN) plays a critical role in sperm function and male fertility. The aim of this study was to determine whether variants of the EPPIN gene are risk factors for idiopathic male infertility.Methods: All subjects, including 473 idiopathic infertile men and 198 fertile controls, underwent complete historical and physical examinations. Each subject donated 5 ml of peripheral blood for genomic DNA extraction and serum testosterone evaluation and an ejaculate for semen analysis. The semen analysis was performed by computer-assisted semen analysis system. The serum testosterone level was evaluated by radioimmunoassay. Four tagging single-nucleotide polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism.Results: We have demonstrated a significant decreased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs2231829, and an increased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs11594. However, among men with normal semen parameters, there were no differences in risk for these genotypes. Furthermore, no significant differences were found for the other variants, rs6124715 and rs2227290, on the risk of male infertility with normal or abnormal semen parameters. Similar serum testosterone levels among different EPPIN genotypes were observed for each group.Conclusions: These results suggest that different variants in the EPPIN gene may have different relationships with idiopathic male infertility and men carrying these variants have a decreased or increased risk of abnormal semen parameters associated with male infertility. [ABSTRACT FROM AUTHOR]