Maternal tumor necrosis factor receptor 2 gene variants associated with pre-eclampsia in Tunisian women

Aim: The tumor necrosis factor receptor 2 (TNFR2) is expressed in placental tissue and it is involved in immune responses, inflammation, angiogenesis and blood pressure regulation; which makes it an attractive pre-eclampsia (PE) candidate gene. Furthermore, TNFR2 expression is altered in the first trimester in placentas of women who are destined to develop PE. Therefore, we examined the association between maternal and fetal genetic variants of TNFR2 and PE.

Material and methods: Women with PE (n = 157) and their offspring with PE (n = 60) were compared to a control group of women (n = 97) and their offspring (n = 52) in the same Tunisian hospital-based population. We genotyped by polymerase chain reaction and restriction fragment length polymorphism the T/G polymorphism at position 676 in exon 6 (rs1061622) of the TNFR2 gene and examined its association with PE.

Results: The frequencies of TNFR2 (G/G) genotype and G allele were higher in the mothers with PE (n = 154) compared to the control group (15.3% vs 4.1% and 37% vs 26.3%, respectively); furthermore, the difference reached statistical significance (P = 0.002, odds ratio = 4.9; 95% confidence interval: 1.69-17.4 and P = 0.03, odds ratio = 1.69; 95% confidence interval: 1.03-2.8, respectively). In contrast, the fetal genotype and allele frequencies of this polymorphism had no effect on the risk of PE.

Conclusions: The exon 6 polymorphism in TNFR2 (rs1061622) or a gene at proximity is associated specifically with PE at least in the Tunisian population and could increase the risk for PE for mothers carrying the homozygote minor allele. Nevertheless, these results need to be confirmed in other populations.