['To evaluate the single nucleotide polymorphisms and expression of KIR2DL4 (killer cell immunoglobulin-like receptors) gene in pre-eclampsia patients.', 'KIR2DL4 gene polymorphisms were detected in 100 patients with pre-eclampsia and 100 healthy pregnant women, respectively, by using PCR-SS. Then, the expression of KIR2DL4 was measured in 5 cases of placentas tissues with pre-eclampsia and normal pregnancies by using qRT-PCR.', 'Compared with healthy controls, 16 loci of single nucleotide polymorphisms (SNP) were identified in pre-eclampsia patients, including 7 new polymorphisms loci. But, no significant difference was found in genotype distributions and allele frequencies in pre-eclampsia and controls (P>0.05). However, qRT-PCR results showed that KIR2DL4 mRNA in placenta tissues with pre-eclampsia was significantly lower than those with normal pregnancy, and the difference was statistically significant.'] Does kIR2DL4 expression rather than its single nucleotide polymorphisms correlate with pre-eclampsia?