Single nucleotide polymorphisms of the maternal cystathionine-beta-synthase gene are associated with preeclampsia

Preeclampsia (PE), a severe pregnancy complication characterized by maternal hypertension and proteinuria, is associated with endothelial dysfunction. Homocysteine (converted by cystathionine-beta-synthase (CBS)) and H 2 S levels are altered during PE and placental CBS gene expression is decreased. As since single nucleotide polymorphisms (SNPs) can affect CBS expression and/or function, we studied CBS SNPs in patients with PE. Controls ( n  = 81), severe ( n  = 60) and mild PE ( n  = 39) cases were genotyped for 6 tag SNPs in the CBS locus. Plasma homocysteine, cysteine and cystathionine during pregnancy were analyzed and urinary sulfate was measured after pregnancy in 28 of the cases and controls. Women with severe PE less often had the minor allele for rs11203172 (OR[95%CI] = 0.46[0.22–0.95], p p p In conclusion, CBS SNPs are associated with decreased and increased risk to develop PE. Decreased cysteine concentrations in healthy pregnant women having the minor allele for rs11203172, may be due to an increased conversion of cysteine to H 2 S by CBS. These women may have higher H 2 S levels, positively affecting placentation and vascular function during pregnancy and decreasing their risk to develop PE.