Polymorphism of Vitamin D Receptor (re2228570) in Sera of Coronary Artery Diseases and its Association with Various Anthropometric and Biochemical Parameters

Abstract

 Objective : Coronary artery disease is increasing and accounts for a high proportion among others diseases. In Iraq various studies have been reported that the polymorphism of vitamin D receptor VDR-Fok I gene like rs 2228570 are associated with CAD patients.

Aim: This study was aimed to investi­gate the association between the SNP of VDR Fok I (rs2228570) gene with various anthropometric and biochemical parameters as a risk for CAD in Iraqi population.

Methods and Materials :  The  current case - control study consisted of  300 samples , 150 of them were obtained from CAD patients who underwent the angiography  department – heart centre – Al-Hussein Teaching Hospital, Al-Hussein Medical City / Holy Kerbala - Iraq  and  another 150 healthy control samples. Phenotypic data included body mass index (BMI), levels of fasting blood sugar (FBS), lipid profile, and blood urea, serum creatinine. Genotyping of rs2228570 polymorphism was carried out by PCR–RFLP method. DNA was extracted from genomic whole blood and genotyping was achieved with specific primers to amplify fragments for digestion with restriction enzymes. The enzyme Fok I was used for the digestion of VDR gene product followed by electrophoresis on agarose gel. Various statistical analyses were applied to analyse the data.

Result:  Digestion of   VDR – Fok I gene product  (PCR-product ) exhibited an amplicon size of 273 bp, when this amplicon digested with Fok I enzyme, it gives three genotypes indicated one (273bp), two (75 bp + 198  bp) and three (75 bp + 198 bp + 273 bp ) bands for those with wild type (TT), homozygous (CC) and heterozygous (TC) genotypes respectively. Genotype frequencies of rs2228570 polymorphism were found to be consistent with Hardy–Weinberg equilibrium with allele frequencies of TT wild genotype (33.3%), TC heterozygous genotype (46.7%), and CC homozygous genotype (20%) in cases of  CAD  group while  66.7%, 30 % and 3.3 % for wild, heterozygous, and homozygous in the control group respectively. The homozygous genotype (CC) was significantly (OR= 7.25, CI 2.74-19.20 , P<0.001 ) increased the risk of CAD seven and quarter folds with respect to those of the wild type (TT) after adjustment for age, sex and BMI, while the TC genotype significantly (OR =  2.04, CI 95%  ; 1.27-3.28 , P<0.001) raised the risk of CAD by two folds. Co-dominant genotypes of rs2228570 polymorphism exhibited significant association with anthropometric and biochemical parameters such as BMI, and  lipid profile among  patients  groups as compared with control groups.

Conclusion:  The obtained results improved that the gene polymorphism of VDR-Fok I  was associated with high risk for development and progression of CAD  and exhibited a significant association with increased BMI and lipid profile of coronary artery diseases of Iraqi population.