Impact of maternal endothelial nitric oxide synthase gene polymorphisms on blood pressure, protein excretion and fetal outcome in pregnancy.

A genetic association study was conducted to assess whether genetically determined alterations of the nitric oxide system are associated with clinical markers of pre-eclampsia. A large number of Caucasian women were consecutively included after delivery and genotyped for the endothelial nitric oxide synthase gene (NOS3) polymorphisms G894T, T789C (n=1502) and intron 4a/b (n=2186). There are no significant differences in mean blood pressure (BP), protein excretion or new-onset peripheral oedema between any of the genotypes over the course of pregnancy. Neither particular haplotypes nor the combined presence of any two alleles is associated with those markers of pre-eclampsia. The maternal polymorphisms do not seem to influence fetal growth, birth weight or the incidence of congenital malformations. We demonstrate in a large Caucasian population that maternal polymorphisms of the NOS3 gene are not related to clinical markers of pre-eclampsia. The functional relevance of the NOS3 variants alone does not seem to be strong enough to affect BP regulation during pregnancy.