Association between vitamin D receptor ApaI and TaqI gene polymorphisms and gestational diabetes mellitus in an Iranian pregnant women population

Abstract

It has been proposed that variants of the nuclear vitamin D receptor (VDR) gene are associated with a susceptibility to type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM). Our study was aimed to evaluate a possible association between the VDR ApaI (rs7975232) and TaqI (rs731236) gene polymorphisms and susceptibility to GDM in an Iranian pregnant women population. This case-control study was performed on a population of pregnant Iranian women, including 157 GDM and 157 non-GDM subjects.VDR ApaI and TaqI polymorphisms were assessed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Our finding showed that the genotypes frequency of VDR ApaI polymorphism was significantly different between GDM and non-GDM groups (χ(2)=8.5, P=0.014). The CC genotype increased the risk of GDM as compared to the AA genotype (AA vs.CC, OR=2.996, 95% CI=1.278-7.022, P=0.012). The genotype and allele frequencies of VDR TaqI polymorphism were significantly different between GDM and non-GDM subjects (χ(2)=7.27, P=0.026, χ(2)=4.08, P=0.043 respectively). A significant protection was shown against GDM in VDR TaqI genotypes and allele (TT vs.TC, OR=0.523, 95% CI=0.23-0.84, P=0.007, TT vs. TC+CC, OR=0.546, 95% CI=0.35-0.86, P=0.009, T vs. C, OR=0.711, 95% CI=0.511-0.99, P=0.043). In conclusion, our findings show a significant association between VDR ApaI and TaqI gene polymorphisms and the GDM at the investigated loci.

Keywords: ApaI; Gestational diabetes mellitus; Polymorphism; TaqI; Vitamin D receptor.