Genetic association of vitamin D receptor polymorphisms (ApaI, BsmI, and FokI) with gestational diabetes mellitus in North Indian women: a case-control study.

Background: Gestational diabetes mellitus (GDM) affects nearly 14% of pregnancies and imposes an increased risk of adverse outcomes for both pregnant women and their developing babies. This study examined the genetic association of vitamin D receptor (VDR) variants (ApaI, BsmI, and FokI) with GDM in the North Indian population.

Methods: Tetra-ARMS PCR was used for genotyping of VDR variants followed by Sanger sequencing validation. The genotypes of VDR variants, Odds ratio (OR) and confidence interval (CI) were further analyzed in GDM and determined by different genetic models.

Results: The C allele of ApaI (rs7975232) genotype significantly associated with increased risk of GDM compared to the TT genotype carrying pregnant women. The A allele of BsmI, and A allele of FokI genotypes was found as a risk factor for GDM. Sanger sequencing confirmed the changes in ApaI (T/C), BsmI (A/G), and FokI (A/G) gene sequence which linked to GDM. The circulatory vitamin D3 levels were significantly lower in GDM patients whereas, homozygous genotypes of ApaΙ (CC, P < 0.0884), BsmI (GG, P < 0.8192) and FokI (GG, P < 0.0303) was associated with vitamin D deficiency. On other hand, mother age, blood glucose and glycated haemoglobin (HbA1c) were significantly higher in the GDM group vs. the control group.

Conclusion: VDR ApaI (rs7975232) and FokI (rs2228570) polymorphisms, HbA1c level, and vitamin D are associated with the risk of GDM in the north Indian population. Considering the impact of vitamin D3 level, it is suggested that pregnant Indian women must consider vitamin D supplementation during pregnancy.