Association of vitamin D receptor gene polymorphisms BsmI (rs 1544410) and TaqI rs (731236) with the type 2 diabetes mellitus in Iraqi Patients from the middle Euphrates region

Association analysis between the VDR gene variants and type 2 diabetes

Background

Type 2 diabetes mellitus (T2DM) is recognized as a complex metabolic which has affected the lives of millions of people around the world. Vitamin D receptor (VDR) gene polymorphisms have been suggested to be a vital contributor to the development of T2DM. However, the association between VDR gene polymorphisms and T2DM remains controversial. We have investigated the association between two VDR gene polymorphisms (rs731236 and rs1544410) and T2DM in an Iranian population.

Methods

A total of 148 T2DM patients and 100 normal controls were recruited in this study. We used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis to perform genotyping.

Results

The results of the present research revealed that the frequency of the rs731236 C allele was significantly higher in T2DM patients than in normal controls (p = 0.044). The CC genotype of rs731236 was connected with an increased risk of T2DM (OR = 2.85, 95% CI = 1.06-7.69, p = 0.039). However, no significant difference in the frequency of the rs1544410 C allele between T2DM patients and normal controls was observed (p = 0.918).

Conclusion

Our findings were suggestive of the rs731236 polymorphism of the VDR as a risk factor for developing T2DM in the Iranian population, while rs1544410 polymorphism may not be associated with T2DM susceptibility. Further research is needed to approve these findings in other populations and to clarify the underlying mechanisms involved in such an association.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01323-0.

Delving the vitamin D receptor variation and expression profiles in the context of type 2 diabetes among families

BACKGROUND

Vitamin D is essential for insulin secretion and sensitivity. Consequently, its inadequacy is linked to higher insulin resistance and Type 2 Diabetes (T2D). The Vitamin D receptor (VDR) gene is one potential candidate for T2D, and multiple polymorphisms in VDR have been examined in various populations, but no conclusive answers have been provided.

OBJECTIVES

This study was designed to evaluate the susceptibility of VDR gene polymorphism and its expression in diabetic families in Pakistan.

METHODOLOGY

In this family-based study, twenty diabetic families with a positive family history of T2D and at least three T2D patients were recruited from outpatient clinics and public hospitals. The current study comprised 143 individuals with 55 affected and 88 unaffected individuals. Blood samples of the selected families were collected. DNA was extracted from the collected samples and the PCR-RFLP method was followed to identify the genotyping and RT-qPCR for expression. Phenotypic and genotypic pedigrees of the families were developed by the progeny online tool. The association values of SNPs were determined by TDT and DFAM analysis implemented on Plink software.

RESULTS

The results explained a significant familial aggregation among phenotypic characters including Age, Gender, BMI (body mass index), age of disease diagnosis, disease duration, and blood pressure in the probands, affected FDRs (First Degree Relatives) and affected SDRs (Second Degree Relatives). A significant association of rs731236 C/T (OR = 1.522), rs2228570 C/T (OR = 1.327) with p < 0.05. Whereas, for rs1544410 G/A (OR = 0.9706) and rs7975232 T/G (OR = 0.7368) no considerable association evidence was seen (p > 0.05) in families. The mRNA expression of VDR increased threefold (p = 0.0204) in patients compared to controls. Variation-based expression analysis exhibited that the rs2228570 genotype influences the expression.

CONCLUSION

A linkage was found among the FDRs with probands. Variation in the gene VDR at loci rs731236 and rs2228570 was associated with familial T2D. However further research is required to explore more genetic factors that could influence T2D risks in families.