Genetic Predisposition of Diabetes to Coronary Artery Disease Due to ApoE Gene Polymorphism Using Allele Discrimination Real-Time Analysis as a Diagnostic Tool

Background: The Apolipoprotein E (ApoE) gene plays a pivotal role in facilitating the removal of lipoproteins and stands as a prominently investigated candidate in the context of type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD). Lipoprotein-linked mechanisms have been implicated in causing cardiovascular impairment among individuals with diabetes. This research was conducted to ascertain the relationship between ApoE genetic variations and the occurrence of T2DM with CAD, as well as its influence on the levels of lipids in the bloodstream within the Iraqi population. These findings offer potential avenues for primary prevention against the onset and progression of bothT2DM and CAD. Method: This study was conducted based on 400 participants, subdivided into 200 T2DM patients with coronary artery disease and 200 normal individuals. To assess the potential risk association of ApoE, logistic regression analysis was employed to derive odds ratios (OR) and corresponding 95% confidence intervals (CI). Results: The frequency ratio of the E3/E4 genotype and the ϵ4 allele among patients affected by both CAD and T2DM exhibited a clear increase. The odds ratios (OR), accompanied by their respective confidence intervals (CI) and p-values, were detailed as follows: for carriers of the E3/E4 genotype, the OR was 4.8 with a 95% CI of 2.4 to 9.46, and a p-value of 0.0001; for E2/E2 carriers, the OR was 1.3 with a 95% CI of 0.18 to 9.21, and a p-value of 0.81; for E2/E3 carriers, the OR was 0.89 with a 95% CI of 0.46 to 1.7, and a p-value of 0.7; for E2/E4 carriers, the OR was 3.84 with a 95% CI of 0.4 to 37.34, and a p-value of 0.25; and for E4/E4 carriers, the OR was 4.3 with a 95% CI of 1.15, and a p-value of 0.03. In comparison to the ϵ3/3 genotype, the E3/4 genotype was significantly associated with an elevated risk in individuals with T2DM and CAD. Notably, the plasma levels of low-density lipoprotein cholesterol (LDL-C) displayed marked variations across the three distinct ApoE isoforms. Moreover, patients carrying genotypes containing the ϵ4 allele exhibited lower levels of high-density lipoprotein cholesterol (HDL-C) when compared to those with the E3/E3 genotype. Conclusions: Our findings suggest an association between ApoE gene variations and the presence of both T2DM and CAD, influencing lipid profiles as well.