Association Between Osteoprotegerin Gene Polymorphisms and Severe Pre-Eclampsia in Chinese Women

OBJECTIVE:To investigate the potential association between 163A/G and 950T/C polymorphisms of osteoprotegerin (OPG) gene and severe pre-eclampsia.METHODS:Eighty-five severe pre-eclamptic patients and 81 normal term pregnant women (as control group) were recruited from the Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University during the period from July 2007 to March 2009, and they were all Han population living in Chengdu, China. Genotype and allele frequencies of 163A/G and 950T/C were determined by the PCR-restriction fragment length polymorphism (RFLP) assay. Clinical and biochemical parameters for different alleles between the patients and controls were compared for statistical significance respectively, such as blood pressure, serum creatinine and 24-hour urine protein.RESULTS:The observed and expected genotype counts were consistent with Hardy-Weinberg equilibrium. No significant differences were found in the genotype and allele frequencies of 163A/G and 950T/C polymorphisms between the two groups (P > 0.05). However, in the preeclamptic group, serum creatinine was significantly higher in women with the AG + GG genotypes [(76 ± 24) µmol/L] compared with AA genotype [(56 ± 18) µmol/L]. Reversely, birth weight was lower in the AG + GG genotypes [(2040 ± 721) g] than those in the AA genotype [(2520 ± 810) g], and the P < 0.05, respectively. In the severe pre-eclampsia, 950T/C TT genotype carriers exhibited significantly higher systolic blood pressure [(153 ± 16) mm Hg (1 mm Hg = 0.133 kPa)] and 24-hour urine protein [(4.0 ± 2.5) g] compared with TT + TC carriers [(145 ± 17) mm Hg, (2.9 ± 1.8) g], respectively, furthermore the P < 0.05.CONCLUSIONS:In severe pre-eclampsia, carriers with G allele at position 163A/G has more genetic predisposition than A allele carriers, as well as 950T/C T allele carriers compared with C carriers. Taken together, this study suggested that OPG gene polymorphisms might be associated with some clinical parameters of severe pre-eclampsia.