Endothelial nitric oxide synthase gene polymorphisms (promoter -786T/C, exon 894 G/T and intron G10T) in unexplained female infertility.

ABSTRACT

BACKGROUND/AIMS: Recent investigations in both males and females show that there may also be some genetic risk factors associated with infertility, and endothelial nitric oxide synthase (eNOS) has important functions in implantation. We aimed to investigate the association of three different polymorphisms of eNOS (promoter -786T/C, exon 894 G/T and intron G10T) with unexplained female infertility. MATERIALS AND METHODS: Two groups of patients were included in the study (1) women with unexplained infertility and (2) healthy, fertile women with normal menstrual cycles. eNOS polymorphisms were studied in genomic DNA of each patient by polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: Forty-one women with unexplained infertility and 40 fertile women were included. Baseline physical characteristics and hormonal parameters of the two groups were similar. For eNOS exon 894 G/T polymorphism, the GG homozygotes were significantly lower and the heterozygotes GT were significantly higher in the infertile group than in the control group (p < 0.05). eNOS gene polymorphism both for promoter and intron were similar in the two groups (p > 0.05). CONCLUSION: Altered eNOS protein caused by eNOS exon 894 G/T polymorphism might cause implantation failure, which may be a possible cause of unexplained female infertility.