Association between apolipoprotein E polymorphisms and premature coronary artery disease: a meta-analysis

Influence of apolipoprotein E gene polymorphisms on coronary artery disease in patients undergoing coronary angiography

Objective

Previous studies have shown that apolipoprotein E (ApoE) gene polymorphisms have an impact on coronary artery disease(CAD). However, many studies have small sample sizes and different conclusions. The purpose was to retrospectively study the influence of ApoE gene polymorphisms on CAD.

Methods

This study assessed the influence of different ApoE genotypes on coronary heart disease in patients who received coronary angiography and used multivariate logistic regression to assess the influence of different ApoE genotypes on CAD.

Results

Patients with different ApoE genotypes had no obvious differences in the incidence of hypertension, diabetes or obesity（P > 0.05). Patients with ε2/ε2 had higher incidence of hypertriglyceridemia than patients with other ApoE genotypes, while patients with ε3/ε3 had a lower incidence of hypertriglyceridemia than those with ε3/ε4,ε4/ε4, ε2/ε3 and ε2/ε2（P < 0.05）. Patients with ε3/ε4, ε4/ε4, ε3/ε3 and ε2/ε2 had no significant differences in the severity or incidence of CAD （P > 0.05). ε2/ε4 and ε2/ε3 reduced the risk of high LDL-C, and reduced the severity and incidence of coronary heart（P < 0.05). ε2/ε3 reduced risk of premature coronary artery disease（PCAD）（P < 0.05). ε2/ε3 reduced risk of CAD in patients age <45,age at 60-74 and age ≥74, while ε2/ε4 reduced risk of CAD in patients age ≥74（P < 0.05).

Conclusion

Patients with ε3/ε4, ε4/ε4,ε3/ε3 and ε2/ε2 had no significant differences in the severity and occurrence of CAD. Compared to the isoform ε3 (ε3/ε3), isoform ε4 did not increased the severity and occurrence of CAD. Compared with ApoE other genotypes, ε2/ε3 and ε2/ε4 reduced the risk of high LDL-C and the severity and occurrence of CAD.

Apolipoprotein E E3/E4 genotype is associated with an increased risk of premature coronary artery disease

OBJECTIVE

Dyslipidemia is one of the causes of coronary heart disease (CAD), and apolipoprotein E (APOE) gene polymorphism affects lipid levels. However, the relationship between APOE gene polymorphisms and premature CAD (PCAD, male CAD patients with ≤ 55 years old and female with ≤ 65 years old) risk had different results in different studies. The aim of this study was to assess this relationship and to further evaluate the relationship between APOE gene polymorphisms and PCAD risk in the Hakka population.

METHODS

This study retrospectively analyzed 301 PCAD patients and 402 age matched controls without CAD. The APOE rs429358 and rs7412 polymorphisms were genotyped by polymerase chain reaction (PCR) -chip technique. The distribution of APOE genotypes and alleles between the case group and the control group was compared. The relationship between APOE genotypes and PCAD risk was obtained by logistic regression analysis.

RESULTS

The frequency of the APOE ɛ3/ɛ4 genotype (18.9% vs. 10.2%, p = 0.001) and ε4 allele (11.1% vs. 7.0%, p = 0.007) was higher in the PCAD patients than that in controls, respectively. PCAD patients with ɛ2 allele had higher TG level than those with ɛ3 allele, and controls carried ɛ2 allele had higher HDL-C level and lower LDL-C level than those carried ɛ3 allele. Regression logistic analysis showed that BMI ≥ 24.0 kg/m2 (BMI ≥ 24.0 kg/m2 vs. BMI 18.5-23.9 kg/m2, OR: 1.763, 95% CI: 1.235-2.516, p = 0.002), history of smoking (Yes vs. No, OR: 5.098, 95% CI: 2.910-8.930, p < 0.001), ɛ3/ɛ4 genotype (ɛ3/ɛ4 vs. ɛ3/ɛ3, OR: 2.203, 95% CI: 1.363-3.559, p = 0.001), ε4 allele (ε4 vs. ε3, OR: 2.125, 95% CI: 1.333-3.389, p = 0.002), and TC level (OR: 1.397, 95% CI: 1.023-1.910, p = 0.036) were associated with PCAD.

CONCLUSIONS

In summary, BMI ≥ 24.0 kg/m2, history of smoking, APOE ɛ3/ɛ4 genotype, and TC level were independent risk factors for PCAD. It means that young individuals who are overweight, have a history of smoking, and carried APOE ɛ3/ɛ4 genotype had increased risk of PCAD.

APOE ε4 carriage associates with improved myocardial performance from adolescence to older age

BACKGROUND

Although APOE ε4 allele carriage confers a risk for coronary artery disease, its persistence in humans might be explained by certain survival advantages (antagonistic pleiotropy).

METHODS

Combining data from ~ 37,000 persons from three older age British cohorts (1946 National Survey of Health and Development [NSHD], Southall and Brent Revised [SABRE], and UK Biobank) and one younger age cohort (Avon Longitudinal Study of Parents and Children [ALSPAC]), we explored whether APOE ε4 carriage associates with beneficial or unfavorable left ventricular (LV) structural and functional metrics by echocardiography and cardiovascular magnetic resonance (CMR).

RESULTS

Compared to the non-APOE ε4 group, APOE ε4 carriers had similar cardiac phenotypes in terms of LV ejection fraction, E/e', posterior wall and interventricular septal thickness, and LV mass. However, they had improved myocardial performance resulting in greater LV stroke volume generation per 1 mL of myocardium (higher myocardial contraction fraction). In NSHD (n = 1467) and SABRE (n = 1187), ε4 carriers had a 4% higher MCF (95% CI 1-7%, p = 0.016) using echocardiography. Using CMR data, in UK Biobank (n = 32,972), ε4 carriers had a 1% higher MCF 95% (CI 0-1%, p = 0.020) with a dose-response relationship based on the number of ε4 alleles. In addition, UK Biobank ε4 carriers also had more favorable radial and longitudinal strain rates compared to non APOE ε4 carriers. In ALSPAC (n = 1397), APOE ε4 carriers aged < 24 years had a 2% higher MCF (95% CI 0-5%, p = 0.059).

CONCLUSIONS

By triangulating results in four independent cohorts, across imaging modalities (echocardiography and CMR), and in ~ 37,000 individuals, our results point towards an association between ε4 carriage and improved cardiac performance in terms of LV MCF. This potentially favorable cardiac phenotype adds to the growing number of reported survival advantages attributed to the pleiotropic effects APOE ε4 carriage that might collectively explain its persistence in human populations.

Association of E-Selectin gene polymorphisms and serum E-Selectin level with risk of coronary artery disease in lur population of Iran

BACKGROUND

Adhesion molecules like E-selectin have important role in pathogenesis of atherosclerosis. C1901T and G98T polymorphisms of E-selectin gene and E-selectin serum level may affect the risk of coronary artery disease (CAD).

METHODS

A total of 145 normal individuals and 154 patients diagnosed with CAD from the Lur population of Iran undergoing coronary angiography were enrolled. Genetic polymorphisms of E-selectin were determined using PCR-RFLP. Serum level of soluble E-selectin was measured using Elisa.

RESULTS

T allele in C1901T polymorphism was significantly associated with an increased risk of atherosclerosis (P = 0.018). No significant association was observed for G98T polymorphism. The mean serum level of soluble E-selectin in the patient group was significantly higher than the control group (P < 0.001).

CONCLUSIONS

Allele type in C1901T polymorphism plays a role in increasing the risk of developing CAD. Furthermore, since serum E-selectin level is associated with systemic inflammation, it contributes to the increased risk of the disease.

Biomarkers for Premature Coronary Artery Disease (PCAD): A Case Control Study

Coronary artery disease (CAD) is often associated with the older generation. However, in recent years, there is an increasing trend in the prevalence of CAD among the younger population; this is known as premature CAD. Although biomarkers for CAD have been established, there are limited studies focusing on premature CAD especially among the Malay male population. Thus, the aim of this research was to compare the biomarkers between premature CAD (PCAD) and older CAD (OCAD) among Malay males. Subjects, recruited from the Universiti Kebangsaan Malaysia Medical Centre and National Heart Institution, were divided into four groups: healthy control < 45 years old; premature CAD (PCAD) < 45 years old; healthy control > 60 years old; and older CAD (OCAD) > 60 years old, with n = 30 for each group. Ten potential markers for CAD including soluble sVCAM-1, sICAM-1, interleukin-2, interleukin-6, interleukin-10, Apo-E and Apo-A1, homocysteine, CRP, and vitamin D levels were examined. Our results revealed premature CAD patients had significantly higher values (p < 0.05) of sVCAM-1, CRP, interleukin-6, and vitamin D when compared to the age-matched controls. Similarly, older CAD patients showed higher levels of sVCAM-1, CRP, and interleukin-2 when compared to their age-matched controls. After adjusting for multiple parameters, only CRP remained significant for PCAD and interleukin-2 remained significant for CAD. This indicates that premature CAD and older CAD patients showed different profiles of protein biomarkers. CRP has the potential to become a biomarker for premature CAD while interleukin-2 is a better biomarker for older CAD together with other typical panels of protein biomarkers.

Genetic pleiotropy underpinning adiposity and inflammation in self-identified Hispanic/Latino populations

BACKGROUND

Concurrent variation in adiposity and inflammation suggests potential shared functional pathways and pleiotropic disease underpinning. Yet, exploration of pleiotropy in the context of adiposity-inflammation has been scarce, and none has included self-identified Hispanic/Latino populations. Given the high level of ancestral diversity in Hispanic American population, genetic studies may reveal variants that are infrequent/monomorphic in more homogeneous populations.

METHODS

Using multi-trait Adaptive Sum of Powered Score (aSPU) method, we examined individual and shared genetic effects underlying inflammatory (CRP) and adiposity-related traits (Body Mass Index [BMI]), and central adiposity (Waist to Hip Ratio [WHR]) in HLA participating in the Population Architecture Using Genomics and Epidemiology (PAGE) cohort (N = 35,871) with replication of effects in the Cameron County Hispanic Cohort (CCHC) which consists of Mexican American individuals.

RESULTS

Of the > 16 million SNPs tested, variants representing 7 independent loci were found to illustrate significant association with multiple traits. Two out of 7 variants were replicated at statistically significant level in multi-trait analyses in CCHC. The lead variant on APOE (rs439401) and rs11208712 were found to harbor multi-trait associations with adiposity and inflammation.

CONCLUSIONS

Results from this study demonstrate the importance of considering pleiotropy for improving our understanding of the etiology of the various metabolic pathways that regulate cardiovascular disease development.

The genetic interactions between non-alcoholic fatty liver disease and cardiovascular diseases

The ongoing debate on whether non-alcoholic fatty liver disease (NAFLD) is an active contributor or an innocent bystander in the development of cardiovascular disease (CVD) has sparked interests in understanding the common mediators between the two biologically distinct entities. This comprehensive review identifies and curates genetic studies of NAFLD overlapping with CVD, and describes the colinear as well as opposing correlations between genetic associations for the two diseases. Here, CVD described in relation to NAFLD are coronary artery disease, cardiomyopathy and atrial fibrillation. Unique findings of this review included certain NAFLD susceptibility genes that possessed cardioprotective properties. Moreover, the complex interactions of genetic and environmental risk factors shed light on the disparity in genetic influence on NAFLD and its incident CVD. This serves to unravel NAFLD-mediated pathways in order to reduce CVD events, and helps identify targeted treatment strategies, develop polygenic risk scores to improve risk prediction and personalise disease prevention.

Apolipoprotein E Gene Polymorphism and Coronary Artery Disease Risk Among Patients in Northwest China

PURPOSE

The association between apolipoprotein E (ApoE) gene polymorphisms and the risk of coronary artery disease (CAD) among different populations has been assessed in numerous previous studies, but the results remain inconclusive. The present study aimed to determine the role of ApoE genotypes in CAD risk and the interrelationships between lipid profiles and ApoE alleles and genotypes among the population of northwest China.

PATIENTS AND METHODS

This study was performed on 308 patients with CAD and 308 control participants. ApoE gene polymorphism was analysed using the polymerase chain reaction and hybridization.

RESULTS

The findings indicated that the frequencies of ε3/ε4 genotype and ε4 allele frequency were significantly higher in patients with CAD than in the control participants. ε2 carriers had significantly lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) levels than did ε3 or ε4 carriers among the control participants. However, our study found no significant differences in plasma lipoprotein levels between ɛ2, ɛ3 and ɛ4 carriers in patients with CAD. Moreover, ε4 carriers had significantly higher ApoB, ApoB/ApoA-I levels and significantly lower ApoE levels in both patients with CAD and control participants. ε4 allele presence was associated with a nearly two-fold higher CAD risk. After adjusting for other established risk factors, ε4 allele was an independent risk factor for CAD. After stratified by age (≤ 60 years and >60 years), ε4 allele was indicated to increase the CAD risk 3.3-fold in elderly patients with CAD, but not in young patients with CAD. After stratified by sex, ε4 allele was not a risk factor in females and males patients with CAD.

CONCLUSION

This study provides evidence that the ε4 allele, drinking, smoking, hypertension, and TG and ApoE levels are independent risk factor for CAD among patients in northwest China.

Investigating Effects of Plasma Apolipoprotein E on Ischemic Heart Disease Using Mendelian Randomization Study

BACKGROUND

Observationally plasma apolipoprotein E (apoE) is positively associated with ischemic heart disease (IHD). A Mendelian randomization (MR) study suggesting apoE is unrelated to cardiovascular mortality did not consider specific isoforms. We used MR to obtain estimates of plasma apoE2, apoE3 and apoE4 on IHD, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, triglycerides and apolipoprotein B (apoB).

METHODS

We obtained independent genetic instruments from proteome genome-wide association studies (GWAS) and applied them to large outcome GWAS. We used univariable MR to assess the role of each isoform and multivariable MR to assess direct effects.

RESULTS

In univariable MR, apoE4 was positively associated with IHD (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.09), but apoE2 and apoE3 were less clearly associated. Using multivariable MR an association of apoE2 with IHD (OR 1.16, 95% CI 0.98 to 1.38) could not be excluded, and associations of apoE3 and apoE4 with IHD were not obvious. In univariable MR, apoE2 and apoE4 were positively associated with apoB, and a positive association of apoE2 with LDL cholesterol could not be excluded. Using multivariable MR apoE2 was positively associated with LDL cholesterol, and associations with apoB could not be excluded. After adjusting for apoB, no direct effects of apoE isoforms on IHD were evident.

CONCLUSIONS

Plasma apoE2 and apoE4 may play a role in lipid modulation and IHD. Whether apoE could be a potential therapeutic target requires further clarification when larger genetic studies of apoE isoforms are available.

Age and sex specific effects of APOE genotypes on ischemic heart disease and its risk factors in the UK Biobank

APOE genotypes are associated with ischemic heart disease (IHD), several other cardiovascular diseases and dementia. Previous studies have not comprehensively considered all genotypes, especially ε2ε2, nor associations by age and sex, although IHD incidence differs by sex. In the UK Biobank, including 391,992 white British participants, we compared effects of APOE genotypes on IHD and its risk factors. Compared to the ε3ε3 genotype, ε2ε2 was not clearly associated with IHD but was associated with lower plasma apolipoprotein B (apoB). The ε2ε3 genotype conferred lower IHD risk, systolic blood pressure (SBP), pulse pressure and plasma apoB than ε3ε3. ε3ε4 and ε4ε4 conferred higher IHD risk, higher pulse pressure and plasma apoB, but lower glycated haemoglobin (HbA1c) than ε3ε3. The associations by age and sex were fairly similar, except ε2ε2 compared to ε3ε3 was marginally positively associated with IHD in the younger age group and nominally inversely associated with SBP in men. ε3ε4 compared to ε3ε3 was nominally positively associated with SBP in women. APOE genotypes affect IHD risk increasingly from ε2ε3, ε3ε3, ε3ε4 to ε4ε4, with similar patterns for pulse pressure and plasma apoB, but not for diabetes. Associations with blood pressure differed by sex. Greater understanding of products of APOE and their effects might generate targets of intervention.

Case Report: Hypertriglyceridemia and Premature Atherosclerosis in a Patient With Apolipoprotein E Gene ε2ε1 Genotype

We present a case of a 40-year-old male with premature atherosclerosis, with evidence of both eruptive and tendinous xanthomas, which could imply an increase in both low-density lipoprotein (LDL) and triglyceride (TG) levels. However, his LDL was 2.08 mmol/l, TG -11.8 mmol/l on rosuvastatin 20 mg. Genetic evaluation was performed using a custom panel consisting of 25 genes and 280 variants responsible for lipid metabolism. A rare ε2ε1 genotype of apolipoprotein E was detected. The combination of clinical manifestations and genetic factors in this patient leads to the diagnosis of familial dysbetalipoproteinemia. Implementation of genetic testing into routine clinical practice could not only improve disease diagnostics and management, but also help prevent their development.

Alzheimer's Risk Factors Age, APOE Genotype, and Sex Drive Distinct Molecular Pathways

Evidence suggests interplay among the three major risk factors for Alzheimer's disease (AD): age, APOE genotype, and sex. Here, we present comprehensive datasets and analyses of brain transcriptomes and blood metabolomes from human apoE2-, apoE3-, and apoE4-targeted replacement mice across young, middle, and old ages with both sexes. We found that age had the greatest impact on brain transcriptomes highlighted by an immune module led by Trem2 and Tyrobp, whereas APOE4 was associated with upregulation of multiple Serpina3 genes. Importantly, these networks and gene expression changes were mostly conserved in human brains. Finally, we observed a significant interaction between age, APOE genotype, and sex on unfolded protein response pathway. In the periphery, APOE2 drove distinct blood metabolome profile highlighted by the upregulation of lipid metabolites. Our work identifies unique and interactive molecular pathways underlying AD risk factors providing valuable resources for discovery and validation research in model systems and humans.

New evidence from plasma ceramides links apoE polymorphism to greater risk of coronary artery disease in Finnish adults

apoE, a key regulator of plasma lipids, mediates altered functionalities in lipoprotein metabolism and thus affects the risk of coronary artery disease (CAD). The significance of different apoE polymorphisms remains unclear; although the ε4 allele is clearly associated with increased cholesterol levels (which inform CAD risk), direct studies about apoE polymorphisms on CAD risk and development have yielded controversial results. Furthermore, certain species of ceramides-complex lipids abundant in plasma LDL-are markers of increased risk of myocardial infarction and cardiovascular death. Using a high-throughput MS approach, we quantified 30 molecular plasma ceramide species from a cohort of 2,160 apoE-genotyped (rs7412, rs429358) young adults enrolled in the population-based Cardiovascular Risk in Young Finns Study. We then searched this lipidome data set to identify new indications of pathways influenced by apoE polymorphisms and possibly related to CAD risk. This approach revealed a previously unreported association between apoE polymorphism and a consistently documented high-risk CAD marker, Cer(d18:1/16:0). Compared with the apoE ε3/3 reference group, plasma levels of apoE ε4 were elevated and those of apoE ε2 were lowered in all subjects without evidence of apoE-by-sex interactions. apoE associated with seven ceramides that are connected to atherogenically potent macrophages and/or lipoprotein particles; these associations could indicate a plausible linkage between apoE polymorphism and ceramide metabolism, leading to adverse plasma LDL metabolism and atherogenesis. In conclusion, new evidence from plasma ceramides links apoE polymorphism with an increased risk of CAD and extends our understanding of the role of apoE in health and disease.

Apolipoprotein E genetic variants interact with Mediterranean diet to modulate postprandial hypertriglyceridemia in coronary heart disease patients: CORDIOPREV study

BACKGROUND

We try to explore whether long-term consumption of two healthy dietary patterns (low-fat [LF] diet or Mediterranean diet [MedDiet]) interacts with the apolipoprotein E (APOE) single-nucleotide polymorphisms (SNPs: rs439401, rs440446 and rs7412) modulating postprandial hypertriglyceridemia (ppHTG) in coronary heart disease (CHD) patients.

METHODS AND RESULTS

We selected patients from the CORDIOPREV study with genotyping and who underwent an oral fat load test (FLT) at baseline and after 3 years follow-up (n = 506). After 3 years of follow-up, we found a gene-diet interaction between the APOE rs439401 SNP and MedDiet. Specifically, T-allele carriers in the MedDiet group showed a more significant decrease in postprandial triglycerides (TG: P = 0.03) and large triacylglycerol-rich lipoproteins (TRLs) TG (large TRLs TG; P = 0.01) compared with CC subjects. Consistently, the area under the curve of TG (AUC-TG; P-interaction = 0.03) and AUC-large TRLs TG (P-interaction = 0.02) were significantly lower in T-allele carriers compared with CC subjects.

CONCLUSIONS

The long-term consumption of a MedDiet modulates ppHTG through APOE genetic variants in CHD patients. This gene-diet interaction may contribute to a more precise dietary advice in CHD patients.

The effect of apolipoprotein E polymorphism on serum metabolome - a population-based 10-year follow-up study

Apolipoprotein E (apoE) is the key regulator of plasma lipids, mediating altered functionalities in lipoprotein metabolism - affecting the risk of coronary artery (CAD) and Alzheimer's diseases, as well as longevity. Searching pathways influenced by apoE prior to adverse manifestations, we utilized a metabolome dataset of 228 nuclear-magnetic-resonance-measured serum parameters with a 10-year follow-up from the population-based Young Finns Study cohort of 2,234 apoE-genotyped (rs7412, rs429358) adults, aged 24-39 at baseline. At the end of our follow-up, by limiting FDR-corrected p < 0.05, regression analyses revealed 180/228 apoE-polymorphism-related associations with the studied metabolites, in all subjects - without indications of apoE x sex interactions. Across all measured apoE- and apoB-containing lipoproteins, ε4 allele had consistently atherogenic and ε2 protective effect on particle concentrations of free/esterified cholesterol, triglycerides, phospholipids and total lipids. As novel findings, ε4 associated with glycoprotein acetyls, LDL-diameter and isoleucine - all reported biomarkers of CAD-risk, inflammation, diabetes and total mortality. ApoE-subgroup differences persisted through our 10-year follow-up, although some variation of individual metabolite levels was noticed. In conclusion, apoE polymorphism associate with a complex metabolic change, including aberrations in multiple novel biomarkers related to elevated cardiometabolic and all-cause mortality risk, extending our understanding about the role of apoE in health and disease.

Apolipoprotein E in lipoprotein metabolism, health and cardiovascular disease

Apolipoprotein E (apoE), a 34 kDa circulating glycoprotein of 299 amino acids, predominantly synthesised in the liver, associates with triglyceride-rich lipoproteins to mediate the clearance of their remnants after enzymatic lipolysis in the circulation. Its synthesis in macrophages initiates the formation of high density-like lipoproteins to effect reverse cholesterol transport to the liver. In the nervous system apoE forms similar lipoproteins which perform the function of distributing lipids amongst cells. ApoE accounts for much of the variation in plasma lipoproteins by three common variants (isoforms) that influence low-density lipoprotein concentration and the risk of atherosclerosis. ApoE2 generally is most favourable and apoE4 least favourable for cardiovascular and neurological health. The apoE variants relate to different amino acids at positions 112 and 158: cysteine in both for apoE2, arginine at both sites for apoE4, and respectively cysteine and arginine for apoE3 that is viewed as the wild type. Paradoxically, under metabolic stress, homozygosity for apoE2 may result in dysbetalipoproteinaemia in adults owing to impaired binding of remnant lipoproteins to the LDL receptor and related proteins as well as heparan sulphate proteoglycans. This highly atherogenic condition is also seen with other mutations in apoE, but with autosomal dominant inheritance. Mutations in apoE may also cause lipoprotein glomerulopathy. In the central nervous system apoE binds amyloid β-protein and tau protein and fragments may incur cellular damage. ApoE4 is a strong risk factor for the development of Alzheimer's disease. ApoE has several other physiological effects that may influence health and disease, including supply of docosahexaenoic acid for the brain and modulating immune and inflammatory responses. Genotyping of apoE may have application in disorders of lipoprotein metabolism as well as glomerulopathy and may be relevant to personalised medicine in understanding cardiovascular risk, and the outcome of nutritional and therapeutic interventions. Quantitation of apoE will probably not be clinically useful. ApoE is also of interest as it may generate peptides with biological function and could be employed in nanoparticles that may allow crossing of the blood-brain barrier. Therapeutic options may emerge from these newer insights.

Association study between DNA methylation and genetic variation of APOE gene with the risk of coronary artery disease

Coronary artery disease (CAD) is a common health problem with a high rate of disability and death. Dyslipidemia and altered metabolism of Apo-lipoproteins are involved in the CAD pathogenesis. The current study investigated two common polymorphisms (rs429358 and rs7412) and promoter DNA methylation status of APOE in the Iranian CAD patients and control subjects. Two hundred angiographically documented CAD patients and 200 control subjects were included in the study. The APOE polymorphism analysis was done by PCR-RFLP technique and DNA methylation status was evaluated by methylation specific PCR. The assay of lipid levels was conducted using standard colorimetric protocols. Results indicated that the frequency of ε3/ε4 and ε2/ε3 genotypes was significantly more common in CAD group compared with control group. Relative to wild type genotype (ε3/ε3), CAD patients with ε3/ε4 and ε2/ε3 genotypes displayed significantly higher concentration of total-cholesterol and LDL-cholesterol. The frequency of DNA methylation of APOE was similar between the two studied groups. However, the methylation frequency of APOE gene was significantly higher in triple stenotic vessels relative to single stenotic vessels (P=0.032). In conclusion The present study indicated that the rs429358 and rs7412 polymorphisms are significantly risk factors for development and severity of CAD. Also, APOE methylation status may be involved in the severity but not in the development of CAD.