LINKAGE AND ASSOCIATION STUDIES OF IL1B AND IL1RN GENE POLYMORPHISMS IN PREECLAMPSIA

Objective: To determine whether preeclampsia is either associated with or linked to two polymorphisms in the IL1B gene (IL1B- TaqI and IL1B- 511) and one polymorphism in the IL1RN gene (IL1RN- IVS2). Methods: Genotyping was performed in 150 affected sib-pair families and 104 healthy Dutch blood donors. Genotype and allele frequencies as well as allelic associations were assessed in three groups of unrelated women from these 150 families; 133 with either eclampsia, preeclampsia or the haemolysis, elevated liver enzymes, low platelets (HELLP) syndrome, 101 with preeclampsia only, and 63 with HELLP syndrome only. These frequencies were compared to those in controls. Frequencies of transmitted and nontransmitted haplotypes, inferred from the three polymorphisms, were compared. Allele sharing between affected siblings from all 150 families was assessed by means of multipoint nonparametric affected sib-pair analyses. Results: No significant differences in genotype and allele frequencies were found between the unrelated study groups and controls. No allelic associations were apparent, nor were there differences in frequencies of transmitted and nontransmitted haplotypes within affected families. Excess allele sharing for any of the three polymorphic markers was absent in affected sib-pairs. Conclusions: None of the IL1B and IL1RN polymorphisms provided evidence for either association or linkage with the risk for (pre)eclampsia HELLP syndrome, preeclampsia only or HELLP syndrome only.