Functional single nucleotide polymorphisms (SNPs) of interleukin (IL)-4 -590 (C>T), toll-like receptor (TLR)-2 +2258 (G>A) and matrix metalloproteinase (MMP)-9 -1562 (C>T) were examined by polymerase chain reaction-restriction fragment length polymorphism to identify their merit as genetic markers for pre-eclampsia. One hundred and seventeen pre-eclamptic women and 146 control subjects with uncomplicated singleton pregnancies participated in this study, conducted at Leeds General Infirmary and St James's University Hospital. While the TLR-2 +2258 (G>A) and MMP-9 -1562 (C>T) SNPs failed to present any significant association with pre-eclampsia, there was a marked trend for an association between the IL-4 -590 (C>T) SNP and pre-eclampsia (chi(2)= 5.87, P = 0.055), with a prevalence of TT homozygous women in this group (OR 4.455, 95% CI 1.286-15.350).