Objective: To investigate the association between three polymorphism sites of endothelial nitric oxide synthase (eNOS; -786T>C, 4a4b, and 894G>T) with nonobstructive male infertility.
Design: Prospective case-control study.
Setting: University-based hospital.
Patient(s): Three hundred seventy-one nonobstructive infertile men in azoospermia (n = 184) or ejaculate semen (n = 187) group were enrolled in this study. Two hundred twenty fertile men who had at least one child without any history of requiring assisted reproductive technology were included as the nationwide control group.
Intervention(s): Semen analysis according to the World Health Organization guidelines and cytogenetic and Y chromosome microdeletion assay.
Main outcome measure(s): Three eNOS polymorphisms were investigated to assess its association with male infertility by pyrosequencing and gel electrophoresis.
Result(s): The statistical analysis of three eNOS polymorphisms showed no significant association between the polymorphisms of the control and infertile group. We investigated the sperm parameters depending on the genotypes of the ejaculate semen group. The sperm morphology was found to be significantly associated with the 4a4b polymorphism of eNOS.
Conclusion(s): Endothelial nitric oxide synthase may be important to sperm morphology in infertile men.