Lack of consistent association between endothelial nitric oxide synthase gene polymorphisms, homocysteine levels and recurrent pregnancy loss in tunisian women

PROBLEM: Polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been associated with reduced vascular NO production or increased level of homocysteine, and evaluated as risk factors for recurrent pregnancy loss (RPL). Therefore, in this case-control study, we aimed to determine the effects of some eNOS functional polymorphisms: the 27-bp intron 4 repeat, the 894G/T of exon 7, and the promoter substitution -786T/C, in women with RPL. METHOD OF STUDY: We genotyped 350 patients with RPL and 200 healthy women by polymerase chain reaction (PCR) and restriction fragment length polymorphism-PCR (RFLP-PCR). The homocysteine total plasma concentrations (tHcy) were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: None of the eNOS polymorphisms-related alleles, genotypes, and haplotypes were associated with RPL. The tHcy were similar between patients and controls; no significant association between tHcy levels and eNOS genotypes could be evidenced. CONCLUSION: The present study identified a lack of association between eNOS gene polymorphisms, the risk of RPL and tHcy levels.