Polymorphism in the epidermal growth factor gene is associated with pre-eclampsia and low birthweight

We have previously reported that polymorphism in the epidermal growth factor (EGF) gene is associated with pre-eclampsia and birthweight based on case-control association studies involving two single nucleotide polymorphisms (SNP). We extended that work to investigate other SNP in the EGF gene for their association with pre-eclampsia and the weight of babies at birth.

A population-based DNA collection was genotyped to determine whether the selected SNP were polymorphic in the study population. In total, 175 women with pre-eclampsia and 171 matched normotensive controls were genotyped for the polymorphic SNP using polymerase chain reaction/restriction fragment length polymorphism and MassARRAY Sequenom iPLEX methodology.

The rs3756261A, rs4444903G, rs2237051G haplotype was associated with the highest increased risk of pre-eclampsia (odds ratio: 3.70, 95% confidence interval: 1.38-9.94; P = 0.016). The rs3756261A allele was the one that contributed to this high degree of significance. The same allele was present in the haplotype rs3756261A, rs11568943G, rs2237051G, rs11569017A, rs4698803T (likelihood ratio statistic = 20.4671, d.f. = 3, P-value = 0.0001), which was associated with the lower birthweight.

In this study we found further evidence for the association of polymorphism in the EGF gene with pre-eclampsia and the weight of babies at birth and identified rs3756261A>G as the SNP that makes the most significant contribution to this association. Bioinformatic analysis showed that this effect may be mediated by caudal type homeohox-2, a transcriptional repressor expressed in the trophoblast, for which a binding site is created at this polymorphic site when the rs3756261A allele is present.