ApoE and ApoC-I polymorphisms: association of genotype with cardiovascular disease phenotype in African Americans

Apolipoproteins (apo) E and C-I are components of triglyceride (TG)-rich lipoproteins and impact their metabolism. Functional polymorphisms have been established in apoE but not in apoC-I. We studied the relationship between apoE and apoC-I gene polymorphisms and plasma lipoproteins and coronary artery disease (CAD) in 211 African Americans and 306 Caucasians. In African Americans but not in Caucasians, apoC-I H2-carriers had significantly lower total and LDL cholesterol and apoB levels, and higher glucose, insulin, and HOMA-IR levels compared with H1 homozygotes. Differences across CAD phenotypes were seen for the apoC-I polymorphism. African-American H2-carriers without CAD had significantly lower total cholesterol (P < 0.001), LDL cholesterol (P < 0.001), and apoB (P < 0.001) levels compared with H1 homozygotes, whereas no differences were found across apoC-I genotypes for African Americans with CAD. Among African-American apoC-I H1 homozygotes, subjects with CAD had a profile similar to the metabolic syndrome (i.e., higher triglyceride, glucose, and insulin) compared with subjects without CAD. For African-American H2-carriers, subjects with CAD had a pro-atherogenic lipid pattern (i.e., higher LDL cholesterol and apoB levels), compared with subjects without CAD. ApoC-I genotypes showed an ethnically distinct phenotype relationship with regard to CAD and CAD risk factors.     

APOA5 variants and metabolic syndrome in Caucasians

Apolipoprotein A5 (APOA5) gene variants were reported to be associated with two components of metabolic syndrome (MetS): higher TG levels and lower HDL levels. Moreover, a recent Japanese case-control study found variant -1131T>C associated with MetS itself. Thus, our study systematically analyzed the APOA5 gene for association with lipid parameters, any other features of MetS, including waist circumference, glucose-related parameters, blood pressure, uric acid, and MetS itself in Caucasians. Ten polymorphisms were analyzed in a large fasting sample of the population-based Cooperative Health Research in the Region of Augsburg (KORA) survey S4 (n = 1,354; southern Germany) and in a second fasting sample, the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk (SAPHIR) study (n = 1,770; Austria). Minor alleles of variants -1131T>C, -3A>G, c.56C>G, 476G>A, and 1259T>C were significantly associated with higher TG levels in single polymorphism (P < 0.001) and haplotype (P G was associated with higher risk for MetS [odds ratio (95% confidence interval) = 1.43 (1.04, 1.99), P = 0.03 for KORA and 1.48 (1.10, 1.99), P = 0.009 for SAPHIR). Our study confirms the association of the APOA5 locus with TG and HDL levels in humans. Furthermore, the data suggest a different mechanism of APOA5 impact on MetS in Caucasians, as variant c.56C>G (not analyzed in the Japanese study) and not -1131T>C, as in the Japanese subjects, was associated with MetS.     

Variants at the APOA5 locus, association with carotid atherosclerosis, and modification by obesity: the Framingham Study

Genetic variation at the apolipoprotein A5 gene (APOA5) is associated with increased triglyceride concentrations, a risk factor for atherosclerosis. Carotid intimal medial thickness (IMT) is a surrogate measure of atherosclerosis burden. We sought to determine the association of common APOA5 genetic variants with carotid IMT and stenosis. A total of 2,273 Framingham Offspring Study participants underwent carotid ultrasound and had data on at least one of the five APOA5 variants (-1131T>C, -3A>G, 56C>G, IVS3+476G >A, and 1259T>C). Although none of the individual variants was significantly associated with carotid measures, the haplotype defined by the presence of the rare allele of the 56C>G variant was associated with a higher common carotid artery (CCA) IMT compared with the wild-type haplotype (0.75 vs. 0.73 mm; P < 0.05). The rare allele of each of the -1131T >C, -3A>G, IVS3+476G>A, and 1259T>C variants and the haplotype defined by the presence of the rare alleles in these four variants were each significantly associated with CCA IMT in obese participants. These associations remained significant even after adjustment for triglycerides. APOA5 variants were associated with CCA IMT, particularly in obese participants. The mechanism of these associations and the effect modification by obesity are independent of fasting triglyceride levels.     

First survey of the three gene polymorphisms (PON1 Q192R, eNOS E298D and eNOS C-786T) potentially associated with coronary artery spasm in African populations and comparison with worldwide data

Three polymorphisms, Paraoxonase 1 (PON1) Q192R (C/G), endothelial nitric oxide synthase (eNOS) E298D (G/T) and eNOS T‐786C have been suggested to be potentially associated with coronary artery spasm in Japanese patients. Data on worldwide populations are needed to clarify whether these associations could hold true for other populations. However, few data are available especially in Africans, spasm of which has been suggested to be an aetiology of myocardial infarction. Therefore, these polymorphisms were investigated in three Africans, Ovambos (n = 123), Ghanians (n = 118) and Xhosas (n = 96), together with Japanese (n = 96), by using polymerase chain reaction‐restriction fragment length polymorphism analysis. Genotype‐distributions of all these SNPs in African populations were significantly different from those in Caucasians, whereas were similar to those in Japanese population. African populations exhibit relatively higher frequency of spasm‐associated G192 allele in PON1 Q192R being similar to Japanese population, however frequencies of spasm‐associated T298 allele and –C786 allele in SNP eNOS E298D and T‐786C, respectively, were conversely lower in Africans than Caucasians. Although healthy subjects have been recruited in this study, these findings may provide genetic background for elucidation of aetiology of spasm. Copyright © 2011 John Wiley & Sons, Ltd.     

ApoE genotype affects allele-specific apo[a] levels for large apo[a] sizes in African Americans: the Harlem-Basset Study

The genetic variability of apolipoprotein E (apoE) influences plasma lipoprotein levels, and allele frequencies differ between African Americans and Caucasians. As African Americans have higher lipoprotein [a] (Lp[a]) levels than Caucasians, we investigated the effects of the apoE gene on allele-specific apolipoprotein [a] (apo[a]) levels across ethnicity. We determined apo[a] sizes, allele-specific apo[a] levels (i.e., levels associated with alleles defined by size), and the apoE gene polymorphism in 231 African Americans and 336 Caucasians. African Americans, but not Caucasians, with the apo E2 genotype had lower levels of Lp[a] compared with those with the apo E4 genotype (9.6 vs. 11.2 nmol/l; P = 0.034, expressed as square root levels). Distribution of apo[a] alleles across apoE genotypes were similar between African Americans and Caucasians. Among African Americans with large apo[a], the allele-specific apo[a] level was significantly lower among epsilon2 carriers compared with epsilon3 or epsilon4 carriers (5.4 vs. 6.6 and 7.4 nmol/l, respectively; P < 0.005, expressed as square root levels). In contrast, there was no significant difference in allele-specific apo[a] levels across apoE genotypes among Caucasians. For large apo[a] sizes, apoE genotype contributed to the observed African American-Caucasian differences in allele-specific apo[a] levels.     

APOA1 gene polymorphisms in the South Asian immigrant population in the United States

BACKGROUND:

Coronary artery disease (CAD) is a leading cause of death in the United States. South Asian immigrants (SAIs) from the Indian subcontinent living in the US are disproportionately at higher risk of CAD than other immigrant populations. Unique genetic factors may predispose SAIs to increased risk of developing CAD when adopting a Western lifestyle including a higher-fat diet, more sedentary behavior and additional gene-environment interactions. SAIs are known to have low levels of the protective high density lipoprotein (HDL) and an altered function for Apo-lipoprotein A-1 (ApoA1), the main protein component of HDL cholesterol. One gene that may be genetically distinctive in this population is APOA1 which codes for ApoA-1 protein, a potentially important contributing factor in the development of CAD.

MATERIALS AND METHODS:

DNA sequencing was performed to determine the status of the seven single-nucleotide polymorphisms (SNPs) in the APOA1 gene from 94 unrelated SAI adults. Genotypes, allelic frequencies, and intragenic linkage disequilibrium of the APOA1 SNPs were calculated.

RESULTS:

Several polymorphisms and patterns were common among persons of south Asian ethnicity. Frequencies for SNPs T655C, T756C and T1001C were found to be different than those reported in European Caucasian individuals. Linkage disequilibrium was found to be present between most (13 of 15) SNP pairings indicating common inheritance patterns.

CONCLUSIONS:

SAIs showed variability in the sequence of the APOA1 gene and linkage disequilibrium for most SNPS. This pattern of APOA1 SNPs may contribute to decreased levels of HDL cholesterol reported in SAIs, leading to an increased risk for developing CAD in this population.     

Protective effect of apolipoprotein E2 on coronary artery disease in African Americans is mediated through lipoprotein cholesterol

We studied the relationship of apolipoprotein E (apoE) isoforms and coronary artery disease (CAD) in 224 African Americans and 326 Caucasians undergoing diagnostic coronary angiography. The presence of CAD was defined as >50% stenosis in at least one artery. ApoE allele frequencies were 0.12, 0.62, and 0.26 for epsilon 2, epsilon 3, and epsilon 4, respectively, in African Americans and 0.08, 0.78, and 0.14 for epsilon 2, epsilon 3, and epsilon 4, respectively, in Caucasians. Among African Americans, CAD was present in 9 of 34 epsilon 2 carriers (26%), significantly smaller (P < 0.05) in proportion compared with 39 of 82 epsilon 3 carriers and 43 of 92 epsilon 4 carriers (48% and 47%, respectively), suggesting a protective effect of the epsilon 2 allele. No such difference was seen in Caucasians. In African Americans but not Caucasians, LDL cholesterol was lower in epsilon 2 carriers than in epsilon 3 and epsilon 4 carriers (106 vs. 127 and 134 mg/dl, respectively; P < 0.005). After adjusting for lipid levels, the association between apoE2 and CAD was no longer significant. Thus, the protective effect of apoE2 seen in African Americans could be explained by a favorable lipid profile in epsilon 2 carriers, whereas in Caucasians, the absence of such a protective effect could be attributable to the lack of effect of apoE2 on the lipid profile.     

APOC3/A5 haplotypes, lipid levels, and risk of myocardial infarction in the Central Valley of Costa Rica

Genetic variation in the APOC3 and APOA5 genes has been associated with plasma triglyceride concentrations and may affect the risk of myocardial infarction (MI). To assess whether APOC3/A5 haplotypes are associated with risk of MI, we examined three single-nucleotide polymorphisms (SNPs) in APOC3 (3238C>G, -455T>C, and -482C>T) and six SNPs in the APOA5 gene (-1131T>C, c.-3A>G, c.56C>G, IVS3+476G>A, c.553G>T, and c.1259T>C) in incident cases (n = 1,703) of a first nonfatal MI matched for gender, age, and area of residence with population-based controls (n = 1,703). Conditional logistic regression models, adjusted for potential environmental confounders, were used for analysis. The common APOC3*222 haplotype was more frequent in cases than in controls (17.4% and 13.7%, respectively, P < 0.001) and was associated with increased risk of MI [odds ratio (OR) = 1.27; 95% confidence interval (95% CI), 1.09, 1.48] compared with APOC3*111 wild-type haplotype. This association was independent of the APOA5 SNPs. Although the APOC3 3238G, APOA5 -1131C, APOA5 c.-3G, and APOA5 c.1259C alleles were associated with higher triglyceride plasma concentrations, these effects could not explain the associations with MI in this population. In summary, this study supports the hypothesis that haplotypes in the APOC3 gene but not in the APOA5 gene increase susceptibility to MI.     

Ultraconserved elements in the human genome: association and transmission analyses of highly constrained single-nucleotide polymorphisms

Ultraconserved elements in the human genome likely harbor important biological functions as they are dosage sensitive and are able to direct tissue-specific expression. Because they are under purifying selection, variants in these elements may have a lower frequency in the population but a higher likelihood of association with complex traits. We tested a set of highly constrained SNPs (hcSNPs) distributed genome-wide among ultraconserved and nearly ultraconserved elements for association with seven traits related to reproductive (age at natural menopause, number of children, age at first child, and age at last child) and overall [longevity, body mass index (BMI), and height] fitness. Using up to 24,047 European-American samples from the National Heart, Lung, and Blood Institute Candidate Gene Association Resource (CARe), we observed an excess of associations with BMI and height. In an independent replication panel the most strongly associated SNPs showed an 8.4-fold enrichment of associations at the nominal level, including three variants in previously identified loci and one in a locus (DENND1A) previously shown to be associated with polycystic ovary syndrome. Finally, using 1430 family trios, we showed that the transmissions from heterozygous parents to offspring of the derived alleles of rare (frequency ≤0.5%) hcSNPs are not biased, particularly after adjusting for the rates of genotype missingness and error in the data. The lack of transmission bias ruled out an immediately and strongly deleterious effect due to the rare derived alleles, consistent with the observation that mice homozygous for the deletion of ultraconserved elements showed no overt phenotype. Our study also illustrated the importance of carefully modeling potential technical confounders when analyzing genotype data of rare variants.     

Single nucleotide polymorphisms at the adiponectin locus and risk of coronary heart disease in men and women

Objective: The objective was to examine the association of 5 common single nucleotide polymorphisms (SNPs) at the adiponectin locus with risk of coronary heart disease (CHD) in men and women. Methods and Procedures: We genotyped five common SNPs in the adiponectin gene (rs266729, ?11365C>G; rs822395, ?4034A>C; rs822396, ?3964A>G; rs2241766, +45T>G; and rs1501299, +276G>T) in men (Health Professionals Follow‐up Study) and women (Nurses’ Health Study) in a nested case control setting. Among participants free of cardiovascular disease at baseline, 266 men and 249 women developed non‐fatal myocardial infarction or fatal CHD during 6 and 8 years of follow‐up, respectively. In addition, 564 men had coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty. Using risk set sampling, controls were selected 2:1 matched on age, smoking, and date of blood draw. Results: The ?4034CC genotype was related to an increased risk of non‐fatal myocardial infarction or fatal CHD compared with the AA genotype [relative risk (RR), men, 1.69; 95% confidence interval (CI), 0.99 to 2.89; women, 2.04; 95% CI, 1.20 to 3.49); however, this genotype was not related to risk of coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty or to plasma adiponectin levels. Other SNPs or haplotypes defined by the 5 SNPs were not consistently related to risk of CHD in men and women or to plasma adiponectin levels. Discussion: Our study does not support the hypothesis that these 5 common SNPs in the adiponectin gene play an important role in the development of CHD among men and women, although we cannot exclude an association between the ?4034CC genotype and risk of CHD.     

Apolipoprotein L-I is positively associated with hyperglycemia and plasma triglycerides in CAD patients with low HDL

Apolipoprotein L-I (apoL-I) is present on a subset of HDL particles and is positively correlated with plasma triglycerides (TGs). We measured plasma apoL-I levels in coronary artery disease (CAD) subjects with low HDL who were enrolled in an angiographic CAD prevention trial. At baseline, apoL-I levels (n = 136; range, 2.2-64.1 mug/ml) were right skewed with a large degree of variability. Multivariate analysis for biological determinants of apoL-I revealed that the log of VLDL-TG (+0.17; P < 0.05) and hyperglycemia (HG; +0.26; P < 0.005) independently predicted apoL-I level. Hyperglycemic patients (n = 24) had mean apoL-I levels >50% higher than normoglycemic subjects (n = 112; 13.2 vs. 8.3 mug/ml, respectively; P < 0.001). No relationship between apoL-I level and change in CAD was found (r = 0.06, P = 0.49). Simvastatin-niacin therapy did not alter apoL-I levels (n = 34; P = 0.27), whereas antioxidant vitamins alone increased apoL-I by >50% (n = 36; P < 0.01). Genotyping of a known apoL-I polymorphism (Lys166Glu) did not independently account for any of the variability in apoL-I levels. In conclusion, we found TG and HG to be the strongest predictors of apoL-I within a dyslipidemic CAD population. These data provide further characterization of the novel HDL-associated apoL-I.     

Identification of CAD candidate genes in GWAS loci and their expression in vascular cells

Recent genome-wide association studies (GWAS) have identified 35 loci that significantly associate with coronary artery disease (CAD) susceptibility. The majority of the genes represented in these loci have not previously been studied in the context of atherosclerosis. To characterize the roles of these candidate genes in the vessel wall, we determined their expression levels in endothelial, smooth muscle, and macrophage cells isolated from healthy, prelesioned, and lesioned mouse aortas. We also performed expression quantitative locus (eQTL) mapping of these genes in human endothelial cells under control and proatherogenic conditions. Of the 57 genes studied, 31 were differentially expressed in one or more cell types in disease state in mice, and the expression levels of 8 were significantly associated with the CAD SNPs in human cells, 7 of which were also differentially expressed in mice. By integrating human and mouse results, we predict that PPAP2B, GALNT4, MAPKAPK5, TCTN1, SRR, SNF8, and ICAM1 play a causal role in the susceptibility to atherosclerosis through a role in the vasculature. Additionally, we highlight the genetic complexity of a subset of CAD loci through the differential expression of multiple candidate genes per locus and the involvement of genes that lie outside linkage disequilibrium blocks.     

Effect of apolipoprotein A-V on plasma triglyceride, lipoprotein size, and composition in genetically engineered mice

Transgenic (Tg) mice that overexpress the human apolipoprotein A-V gene (APOA5) yet lack an endogenous mouse apoa5 gene (APOA5 Tg mice) were generated. Subsequently, the effect of human apoA-V expression on plasma triglyceride (TG) concentration and lipoprotein and apolipoprotein distribution was determined and compared with that in mice deficient in apoA-V (apoa5(-/-) mice). NMR analysis of plasma lipoproteins revealed that APOA5 Tg mice had a very low VLDL concentration (26.4 +/- 7.7 nmol/dl), whereas VLDL in apoa5(-/-) mice was 18- fold higher (467 +/- 152 nmol/dl). SDS-PAGE analysis of the d < 1.063 g/ml plasma fraction revealed that the apoB-100/apoB-48 ratio was 14-fold higher in APOA5 Tg versus apoa5(-/-) mice and that the apoE/total apoB ratio was 7-fold greater in APOA5 Tg versus apoa5(-/-) mice. It is anticipated that a reduction in apoB-100/apoB-48 ratio as well as that for apoE/apoB would impair the uptake of VLDL and remnants in apoa5(-/-) mice, thereby contributing to increased plasma TG levels. The concentration of apoA-V in APOA5 Tg mice was 12.5 +/- 2.9 microg/ml, which is approximately 50- to 100-fold higher than that reported for normolipidemic humans. ApoA-V was predominantly associated with HDL but was rapidly and efficiently redistributed to apoA- V-deficient VLDL upon incubation. Consistent with findings reported for human subjects, apoA-V concentration was positively correlated with TG levels in normolipidemic APOA5 Tg mice. It is conceivable that, in a situation in which apoA-V is chronically overexpressed, complex interactions among factors regulating TG homeostasis may result in a positive correlation of apoA-V with TG concentrations.     

Leukocyte telomeres are longer in African Americans than in whites: the National Heart, Lung, and Blood Institute Family Heart Study and the Bogalusa Heart Study

Leukocyte telomere length (LTL) is ostensibly a bio-indicator of human aging. Here we report that African Americans have longer LTL than whites. We studied cross-sectionally 2453 individuals from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study (age = 30–93 years) and the Bogalusa Heart Study (age = 19–37 years), comprising 1742 whites and 711 African Americans. We measured LTL by Southern blots of the terminal restriction fragments length. In 234 participants, telomere repeats were also measured by quantitative polymerase chain reaction (qPCR). Adjusted for age and body mass index (BMI), the respective leukocyte telomere lengths (mean ± SEM) were considerably longer in African Americans than in whites both in the Family Heart Study (7.004 ± 0.033 kb vs. 6.735 ± 0.024 kb, p  < 0.0001) and the Bogalusa Heart Study (7.923 ± 0.063 kb vs. 7.296 ± 0.039 kb, p  < 0.0001). We confirmed the racial effect on LTL by qPCR (3.038 ± 0.565 T/S units for African Americans vs. 2.714 ± 0.487 T/S units for whites, p  < 0.001). Cross-sectionally, sex- and BMI-adjusted LTL became shorter with age (range 19–93 years) at a steeper slope in African Americans than in whites (0.029 kb year⁻¹ vs. 0.020 kb year⁻¹, respectively, p  = 0.0001). We suggest that racial difference in LTL arises from a host of interacting biological factors, including replication rates of hematopoietic stem cells.     

A lack of association between adiponectin polymorphisms and coronary artery disease in a Chinese population

We investigated the association between two single nucleotide polymorphisms (SNPs) in the adiponectin gene (rs822395 and rs266729) and coronary artery disease (CAD) in a case-control study of 198 unrelated Chinese CAD patients (with ≥ 70% coronary stenosis or previous myocardial infarction) and 237 non-CAD controls. The ligase reaction was used to detect SNPs rs822395 and rs266729, and the allelic association of these SNPs with the occurrence and severity of CAD was assessed. There were no significant differences in the genotypic or allelic frequencies of the two SNPs between control and CAD individuals. In addition, there was no association between the two SNPs and the severity of CAD based on the number of diseased vessels. The frequencies of alleles C and G at rs266729 differed significantly between females in the CAD and control groups, but not between males. Female carriers of allele G at rs266729 had a higher risk of CAD compared with allele C carriers (OR = 1.30, 95% CI: 1.09-2.64, p = 0.02). These results indicate a gender-specific effect of the adiponectin gene rs266729 variant in modulating the risk of CAD in women.     

Influence of the APOA5 locus on plasma triglyceride, lipoprotein subclasses, and CVD risk in the Framingham Heart Study

Several polymorphisms in the APOA5 gene have been associated with increased plasma triglyceride (TG) concentrations. However, associations between APOA5 and lipoprotein subclasses, remnant-like particles (RLPs), and cardiovascular disease (CVD) risk have been less explored. We investigated associations of five APOA5 single-nucleotide polymorphisms (SNPs; -1131T>C, -3A>G, 56C>G IVS3+ 476G>A, and 1259T>C) with lipoprotein subfractions and CVD risk in 1,129 men and 1,262 women participating in the Framingham Heart Study. Except for the 56C>G SNP, the other SNPs were in significant linkage disequilibria, resulting in three haplotypes (11111, 22122, and 11211) representing 98% of the population. SNP analyses revealed that the -1131T>C and 56C>G SNPs were significantly associated with higher plasma TG concentrations in both men and women. For RLP and lipoprotein subclasses, we observed gender-specific association for the -1131T>C and 56C>G SNPs. Female carriers of the -1131C allele had higher RLP concentrations, whereas in males, significant associations for RLPs were observed for the 56G allele. Moreover, haplotype analyses confirmed these findings and revealed that the 22122 and 11211 haplotypes exhibited different associations with HDL cholesterol concentrations. In women, the -1131C allele was associated with a higher hazard ratio for CVD (1.85; 95% confidence interval, 1.03-3.34; P = 0.04), in agreement with the association of this SNP with higher RLPs.     

NO Level and Endothelial NO Synthase Gene Polymorphism （Glu298Asp） in the Patients with Coronary Artery Disease from the Turkish Population

A healthy endothelium plays a core role in cardiovascu-lar control [1]. In the endothelial cell, nitric oxide (NO) issynthesized by the endothelial nitric oxide synthase (eNOS)encoded by a 26-exon gene (NOS 3) located on chromo-some 7 [2]. Besides its regulatory functions on vasomotortone and blood flow, endothelial NO is known to inhibitthe platelet activation and modulate migration and growthof the vascular smooth muscle [3]. Indirect evidence sug-gests that alterations of the NO pathwa…     

A preliminary study of human paraoxonase and PON 1 L/M55–PON 1 Q/R 192 polymorphisms in Turkish patients with coronary artery disease

Paraoxonase 1 (PON 1) is a high‐density lipoprotein (HDL)‐associated enzyme with antioxidant function protecting low‐density lipoprotein (LDL) from oxidation. PON 1 has two amino acid polymorphisms in coding region; L/M 55 and Q/R 192. These polymorphisms modulate paraoxonase activity of the enzyme. PON 1 activity decreases in coronary artery disease (CAD). In the present study, distribution of PON 1 L/M 55 and Q/R 192 polymorphisms and the effect of these polymorphisms on the activities of PON 1, and on the severity of CAD in 277 CAD (+) patient and 92 CAD (?) subjects were examined. PON 1 L/M 55 and Q/R 192 genotypes were determined by PCR, RFLP and agarose gel electrophoresis techniques. Genotype distributions and allele frequencies for PON 1 Q/R 192 polymorphism were not significantly different between controls and CAD (+) patient group (p > 0.05), but in genotype and allele distribution of PON 1 L/M55 polymorphism, there was significantly difference among groups (p < 0.05). Genotype distributions for both polymorphisms were not significantly different between subgroups of single‐vessel disease (SVD), double‐vessel disease (DVD) and triple‐vessel disease (TVD). Serum PON 1 activity was lower in CAD (+) group than in controls and this was also statistically significant (p < 0.001). In both groups, the highest PON activities were detected in LL and RR genotypes. In summary, our results suggest that there is an association between the PON 1 L/M 55 polymorphism of paraoxonase and CAD in Turkish patients but not with PON 1 Q/R 192 polymorphism. However, it is hard to correlate these polymorphisms and severity of CAD. Copyright © 2009 John Wiley & Sons, Ltd.     

Progress and promise in understanding the genetic basis of common diseases

Susceptibility to common human diseases is influenced by both genetic and environmental factors. The explosive growth of genetic data, and the knowledge that it is generating, are transforming our biological understanding of these diseases. In this review, we describe the technological and analytical advances that have enabled genome-wide association studies to be successful in identifying a large number of genetic variants robustly associated with common disease. We examine the biological insights that these genetic associations are beginning to produce, from functional mechanisms involving individual genes to biological pathways linking associated genes, and the identification of functional annotations, some of which are cell-type-specific, enriched in disease associations. Although most efforts have focused on identifying and interpreting genetic variants that are irrefutably associated with disease, it is increasingly clear that—even at large sample sizes—these represent only the tip of the iceberg of genetic signal, motivating polygenic analyses that consider the effects of genetic variants throughout the genome, including modest effects that are not individually statistically significant. As data from an increasingly large number of diseases and traits are analysed, pleiotropic effects (defined as genetic loci affecting multiple phenotypes) can help integrate our biological understanding. Looking forward, the next generation of population-scale data resources, linking genomic information with health outcomes, will lead to another step-change in our ability to understand, and treat, common diseases.     

Polymorphism of the Apolipoprotein E Gene and Risk of Myocardial Infarction

The apolipoprotein E (ApoE) gene polymorphism resulting from nucleotide substitutions in exon 4 was analyzed in Russian and Tatar patients with myocardial infarction (MI) from Bashkortostan. Alleles 2, 3, and 4 were identified by PCR. The genotype frequency distribution proved to be age-dependent in healthy Russians, genotype 2/3 increasing in frequency in subjects over 45. Russians who suffered MI under 45 had lower frequencies of genotype E3/3 (50.00% vs. 75.47% in controls of the same age, = 0.013, OR = 0.33) and allele 3 (72.12% vs. 85.85%, = 0.020, OR = 0.43) and a higher frequency of allele 4 (22.12% vs. 10.38%, = 0.030, OR = 2.45). Russians who suffered MI complicated by cardiogenic shock (CS) had a significantly higher frequency of genotype 3/4 and lower frequencies of genotype 3/3 and allele 3 as compared with MI patients without CS. In Tatars, genotype 4/4 occurred at a frequency of 14.29% in patients who suffered MI under 45, and was not detected in healthy subjects of the same age ( = 0.024, OR = 17.85). Thus, the ApoE polymorphism was associated with higher risk of MI in Russians and Tatars under 45.