KEYWORDS VDR ApaI ABSTRACTVitamin D deficiency has been associated with the acceleration of the onset of T2DM. The biological effects of vitamin D are mediated by binding to the vitamin D receptor (VDR) which belongs to the steroid receptor superfamily. Although many polymorphisms exist in the VDR gene, their effect on VDR protein function and signalling is unknown. An association between VDR polymorphism and T2DM has been reported in some studies; however, it appears to vary across different populations around the world. Hence this study was carried out to investigate the relationship between VDR gene polymorphisms at three restriction sites ApaI, BsmI, and TaqI and the risk of T2DM in Saudi population. The volunteers were classified according to Fasting Blood Glucose (FBG) test as two groups, T2DM and normal group. The VDR gene was amplified by polymerase chain reaction (PCR). PCR products were digested using restriction enzymes: ApaI, TaqI, and BsmI and the bands were visualised by agarose gel electrophoresis and ethidium bromide dye under UV. The results of the current study showed a significant difference in genotypes and allele frequencies of the VDR gene polymorphisms at the ApaI site between T2DM patients and control groups.

Vitamin D is primarily associated with a major role in bone formation. It is also associated with onset and progniosis of diseases such as diabetes, cancer and cardiovascular diseases. In Saudi Arabia, the prevalence of DM is one of the highest reported in the world. There is accumulating evidence suggesting an association between the DM and vit D deficiency. This study was proposed to establish a possible correlation between gestational diabetes mellitus (GDM) and the polymorphisms in the vitamin D receptor (VDR) gene at the sites namely TaqI, BsmI, and ApaI. Results of this study revealed that homozygous recessive genotype tt of the TaqI site with GDM. This study will help to establish the role of VDR gene in occurrence of various subsets of DM which is a major metabolic disorder in Saudi Arabia.

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