APOE/C1/C4/C2 gene cluster genotypes, haplotypes and lipid levels in prospective coronary heart disease risk among UK healthy men

Sequence Variant Analysis of the APOCII Locus among an Arab Cohort

Apolipoprotein CII (ApocII) plays a key role in regulating lipoprotein lipase (LPL) in lipid metabolism and transport. Numerous polymorphisms within APOCII are reportedly associated with type 2 diabetes mellitus (T2DM), dyslipidemia, and aberrant plasma lipid levels. Few studies have investigated sequence variants at APOCII loci and their association with metabolic disorders. This study aimed to identify and characterize genetic variants by sequencing the full APOCII locus and its flanking sequences in a sample of the Kuwaiti Arab population, including patients with T2DM, hypertriglyceridemia, non-Arab patients with T2DM, and healthy Arab controls. A total of 52 variants were identified in the noncoding sequences: 45 single nucleotide polymorphisms, wherein five were novel, and seven insertion deletions. The minor allele frequency (MAF) of the 47 previously reported variants was similar to the global MAF and to that reported in major populations. Sequence variant analysis predicted a conserved role for APOCII with a potential role for rs5120 in T2DM and rs7133873 as an informative ethnicity marker. This study adds to the ongoing research that attempts to identify ethnicity-specific variants in the apolipoprotein gene loci and associated LPL genes to elucidate the molecular mechanisms of metabolic disorders.

Comprehensive in-silico analysis of deleterious SNPs in APOC2 and APOA5 and their differential expression in cancer and cardiovascular diseases conditions

Genetic variations in APOC2 and APOA5 genes involve activating lipoprotein lipase (LPL), responsible for the hydrolysis of triglycerides (TG) in blood and whose impaired functions affect the TG metabolism and are associated with metabolic diseases. In this study, we investigate the biological significance of genetic variations at the DNA sequence and structural level using various computational tools. Subsequently, 8 (APOC2) and 17 (APOA5) non-synonymous SNPs (nsSNPs) were identified as high-confidence deleterious SNPs based on the effects of the mutations on protein conservation, stability, and solvent accessibility. Furthermore, based on our docking results, the interaction of native and mutant forms of the corresponding proteins with LPL depicts differences in root mean square deviation (RMSD), and binding affinities suggest that these mutations may affect their function. Furthermore, in vivo, and in vitro studies have shown that differential expression of these genes in disease conditions due to the influence of nsSNPs abundance may be associated with promoting the development of cancer and cardiovascular diseases. Preliminary screening using computational methods can be a helpful start in understanding the effects of mutations in APOC2 and APOA5 on lipid metabolism; however, further wet-lab experiments would further strengthen the conclusions drawn from the computational study.

Autoimmune Reaction Associated With Long COVID Syndrome and Cardiovascular Disease: A Genetic Case Report

A 35-year-old woman with history of cardiovascular disease presented with shortness of breath, lightheadedness, fatigue, chest pain, and premature ventricular contractions 3 weeks after her second COVID-19 vaccine. Symptoms subsided following catheter ablation and ibuprofen except for chest pain and fatigue, which persisted following ablation and subsequent SARS-CoV-2 infection. The case suggests causal associations between COVID-19 vaccine/infection and recurrence of cardiovascular disease, including long-COVID-like symptoms. (Level of Difficulty: Advanced.).

Role of apolipoprotein C1 in lipoprotein metabolism, atherosclerosis and diabetes: a systematic review

Apolipoprotein C1 (apoC1) is a small size apolipoprotein whose exact role is not totally clarified but which seems to modulate significantly the metabolism of lipoproteins. ApoC1 is involved in the metabolism of triglyceride-rich lipoproteins by inhibiting the binding of very low density lipoproteins (VLDL) to VLDL-receptor (VLDL-R), to low density lipoprotein receptor (LDL-R) and to LDL receptor related protein (LRP), by reducing the activity of lipoprotein lipase (LPL) and by stimulating VLDL production, all these effects leading to increase plasma triglycerides. ApoC1 takes also part in the metabolism of high density lipoproteins (HDL) by inhibiting Cholesterol Ester Transfer Protein (CETP). The functionality of apoC1 on CETP activity is impaired in diabetes that might account, at least in part, for the increased plasma CETP activity observed in patients with diabetes. Its different effects on lipoprotein metabolism with a possible role in the modulation of inflammation makes the net impact of apoC1 on cardiometabolic risk difficult to figure out and apoC1 might be considered as pro-atherogenic or anti-atherogenic depending on the overall metabolic context. Making the link between total plasma apoC1 levels and the risk of cardio-metabolic diseases is difficult due to the high exchangeability of this small protein whose biological effects might depend essentially on its association with VLDL or HDL. The role of apoC1 in humans is not entirely elucidated and further studies are needed to determine its precise role in lipid metabolism and its possible pleiotropic effects on inflammation and vascular wall biology. In this review, we will present data on apoC1 structure and distribution among lipoproteins, on the effects of apoC1 on VLDL metabolism and HDL metabolism and we will discuss the possible links between apoC1, atherosclerosis and diabetes.

Loss of FOXA2 induces ER stress and hepatic steatosis and alters developmental gene expression in human iPSC-derived hepatocytes

FOXA2 has been known to play important roles in liver functions in rodents. However, its role in human hepatocytes is not fully understood. Recently, we generated FOXA2 mutant induced pluripotent stem cell (FOXA2^-/-iPSC) lines and illustrated that loss of FOXA2 results in developmental defects in pancreatic islet cells. Here, we used FOXA2^-/-iPSC lines to understand the role of FOXA2 on the development and function of human hepatocytes. Lack of FOXA2 resulted in significant alterations in the expression of key developmental and functional genes in hepatic progenitors (HP) and mature hepatocytes (MH) as well as an increase in the expression of ER stress markers. Functional assays demonstrated an increase in lipid accumulation, bile acid synthesis and glycerol production, while a decrease in glucose uptake, glycogen storage, and Albumin secretion. RNA-sequencing analysis further validated the findings by showing a significant increase in genes associated with lipid metabolism, bile acid secretion, and suggested the activation of hepatic stellate cells and hepatic fibrosis in MH lacking FOXA2. Overexpression of FOXA2 reversed the defective phenotypes and improved hepatocyte functionality in iPSC-derived hepatic cells lacking FOXA2. These results highlight a potential role of FOXA2 in regulating human hepatic development and function and provide a human hepatocyte model, which can be used to identify novel therapeutic targets for FOXA2-associated liver disorders.

Genetic Variants at the APOE Locus Predict Cardiometabolic Traits and Metabolic Syndrome: A Taiwan Biobank Study

Several apolipoprotein genes are located at the APOE locus on chromosome 19q13.32. This study explored the genetic determinants of cardiometabolic traits and metabolic syndrome at the APOE locus in a Taiwanese population. A total of 81,387 Taiwan Biobank (TWB) participants were enrolled to undergo genotype−phenotype analysis using data from the Axiom Genome-Wide CHB arrays. Regional association analysis with conditional analysis revealed lead single-nucleotide variations (SNVs) at the APOE locus: APOE rs7412 and rs429358 for total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol levels; CLPTM1 rs3786505 and rs11672748 for LDL and HDL cholesterol levels; and APOC1 rs438811 and APOE-APOC1 rs439401 for serum triglyceride levels. Genotype−phenotype association analysis revealed a significant association of rs429358 and rs438811 with metabolic syndrome and of rs7412, rs438811, and rs439401 with serum albumin levels (p < 0.0015). Stepwise regression analysis indicated that CLPTM1 variants were independently associated with LDL and HDL cholesterol levels (p = 3.10 × 10−15 for rs3786505 and p = 1.48 × 10−15 for rs11672748, respectively). APOE rs429358 and APOC1 rs438811 were also independently associated with metabolic syndrome (p = 2.29 × 10−14) and serum albumin levels (p = 3.80 × 10−6), respectively. In conclusion, in addition to APOE variants, CLPTM1 is a novel candidate locus for LDL and HDL cholesterol levels at the APOE gene region in Taiwan. Our data also indicated that APOE and APOC1 variants were independently associated with metabolic syndrome and serum albumin levels, respectively. These results revealed the crucial role of genetic variants at the APOE locus in predicting cardiometabolic traits and metabolic syndrome.

Human apolipoprotein C1 transgenesis reduces atherogenesis in hypercholesterolemic rabbits

BACKGROUND AND AIMS

Apolipoprotein (apo) C1 is a 6.6 kDa protein associated with HDL and VLDL. ApoC1 alters triglyceride clearance, and it also favors cholesterol accumulation in HDL, especially by inhibiting CETP in human plasma. Apart from studies in mice, which lack CETP, the impact of apoC1 on atherosclerosis in animal models expressing CETP, like in humans, is not known. This study aimed at determining the net effect of human apoC1 on atherosclerosis in rabbits, a species with naturally high CETP activity but with endogenous apoC1 without CETP inhibitory potential.

METHODS

Rabbits expressing a human apoC1 transgene (HuApoC1Tg) were generated and displayed significant amounts of human apoC1 in plasma.

RESULTS

After cholesterol feeding, atherosclerosis lesions were significantly less extensive (-22%, p < 0.05) and HDL displayed a reduced ability to serve as CETP substrates (-25%, p < 0.05) in HuApoC1Tg rabbits than in WT littermates. It was associated with rises in plasma HDL cholesterol level and PON-1 activity, and a decrease in the plasma level of the lipid oxidation markers 12(S)-HODE and 8(S)HETE. In chow-fed animals, the level of HDL-cholesterol was also significantly higher in HuApoC1Tg than in WT animals (0.83 ± 0.11 versus 0.73 ± 0.11 mmol/L, respectively, p < 0.05), and it was associated with significantly lower CETP activity (cholesteryl ester transfer rate, -10%, p < 0.05; specific CETP activity, -14%, p < 0.05).

CONCLUSIONS

Constitutive expression of fully functional human apoC1 in transgenic rabbit attenuates atherosclerosis. It was found to relate, at least in part, to the inhibition of plasma CETP activity and to alterations in plasma HDL.

Blood miR-1275 is associated with risk of ischemic stroke and inhibits macrophage foam cell formation by targeting ApoC2 gene

Apolipoprotein C2 (ApoC2) is an important member of the apolipoprotein C family and functions as a major activator of lipoprotein lipase (LPL). In cardiovascular and cerebrovascular systems, the lipolytic activity of the LPL-ApoC2 complex is critical for the metabolism of triglyceride-rich lipoproteins and contributes to the pathogenesis of ischemic stroke (IS). However, the regulation of ApoC2 in IS development remains unclear. In this study, we first explored potential ApoC2-targeting microRNAs (miRNAs) by bioinformatics tool and compared the miRNA expression profiles in the blood cells of 25 IS patients and 25 control subjects by miRNA microarray. miR-1275 was predicted to bind with the 3' untranslated region of ApoC2, and a significant reduction of blood miR-1275 levels was observed in IS patients. Dual-luciferase reporter assay and quantitative RT-PCR confirmed the regulation of ApoC2 by miR-1275 in THP-1 derived macrophages. miR-1275 also inhibited cellular uptake of ox-LDL and suppressed formation of macrophage foam cell. Furthermore, the whole blood miR-1275 levels were validated in 279 IS patients and 279 control subjects by TaqMan assay. miR-1275 levels were significantly lower in IS cases and logistic regression analysis showed that miR-1275 level was negatively associated with the occurrence of IS (adjusted OR, 0.76; 95% CI, 0.69-0.85; p < 0.001). Addition of miR-1275 to traditional risk factors showed an additive prediction value for IS. Our study shows that blood miR-1275 levels were negatively associated with the occurrence of IS, and miR-1275 might exert an athero-protective role against the development of IS by targeting ApoC2 and blocking the formation of macrophage foam cells.

Apolipoprotein C1: Its Pleiotropic Effects in Lipid Metabolism and Beyond

Apolipoprotein C1 (apoC1), the smallest of all apolipoproteins, participates in lipid transport and metabolism. In humans, APOC1 gene is in linkage disequilibrium with APOE gene on chromosome 19, a proximity that spurred its investigation. Apolipoprotein C1 associates with triglyceride-rich lipoproteins and HDL and exchanges between lipoprotein classes. These interactions occur via amphipathic helix motifs, as demonstrated by biophysical studies on the wild-type polypeptide and representative mutants. Apolipoprotein C1 acts on lipoprotein receptors by inhibiting binding mediated by apolipoprotein E, and modulating the activities of several enzymes. Thus, apoC1 downregulates lipoprotein lipase, hepatic lipase, phospholipase A2, cholesterylester transfer protein, and activates lecithin-cholesterol acyl transferase. By controlling the plasma levels of lipids, apoC1 relates directly to cardiovascular physiology, but its activity extends beyond, to inflammation and immunity, sepsis, diabetes, cancer, viral infectivity, and-not last-to cognition. Such correlations were established based on studies using transgenic mice, associated in the recent years with GWAS, transcriptomic and proteomic analyses. The presence of a duplicate gene, pseudogene APOC1P, stimulated evolutionary studies and more recently, the regulatory properties of the corresponding non-coding RNA are steadily emerging. Nonetheless, this prototypical apolipoprotein is still underexplored and deserves further research for understanding its physiology and exploiting its therapeutic potential.

Diagnostic and prognostic significance of mRNA expressions of apolipoprotein A and C family genes in hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is among the most common and lethal malignancies worldwide. Apolipoproteins (APOs) have been reported increasingly for their relationships with tumors. We aim at exploring the potential relationships of apolipoprotein A (APOA) and apolipoprotein C (APOC) family members with HCC.

METHODS

A data set, containing 212 hepatitis B virus-related HCC patients, was used for analysis. The diagnostic and prognostic ability of APOA and APOC family genes was figured out. Risk score models and nomograms were developed for the HCC prognosis prediction. Moreover, molecular mechanism exploration were identified biological processes and metabolic pathways of these genes involved in. Validation analysis was carried out using online website.

RESULTS

APOA1, APOC1, APOC3, and APOC4 showed robust diagnosis significance (all P < 0.05). APOA4, APOC3, and APOC4 were associated with the overall survival (OS) while APOA4 and APOC4 were linked to recurrence-free survival (RFS, all P ≤ 0.05). Risk score models and nomograms had the advantage of predicting OS and RFS for HCC. Molecular mechanism exploration indicated that these genes were involved in the steroid metabolic process, the PPAR signaling pathway, and fatty acid metabolism. Besides that, validation analysis revealed that APOC1 and APOC4 had an association with OS; and APOC3 was associated with OS and RFS (all P ≤ 0.05).

CONCLUSIONS

APOA1, APOC1, APOC3, and APOC4 are likely to be potential diagnostic biomarkers and APOC3 and APOC4 are likely to be potential prognostic biomarkers for hepatitis B virus-related HCC. They may be involved in the steroid metabolic process, PPAR signaling pathway, and fatty acid metabolism.

Apolipoprotein E-C1-C4-C2 gene cluster region and inter-individual variation in plasma lipoprotein levels: a comprehensive genetic association study in two ethnic groups

The apolipoprotein E-C1-C4-C2 gene cluster at 19q13.32 encodes four amphipathic apolipoproteins. The influence of APOE common polymorphisms on plasma lipid/lipoprotein profile, especially on LDL-related traits, is well recognized; however, little is known about the role of other genes/variants in this gene cluster. In this study, we evaluated the role of common and uncommon/rare genetic variation in this gene region on inter-individual variation in plasma lipoprotein levels in non-Hispanic Whites (NHWs) and African blacks (ABs). In the variant discovery step, the APOE, APOC1, APOC4, APOC2 genes were sequenced along with their flanking and hepatic control regions (HCR1 and HCR2) in 190 subjects with extreme HDL-C/TG levels. The next step involved the genotyping of 623 NHWs and 788 ABs for the identified uncommon/rare variants and common tagSNPs along with additional relevant SNPs selected from public resources, followed by association analyses with lipid traits. A total of 230 sequence variants, including 15 indels were identified, of which 65 were novel. A total of 70 QC-passed variants in NHWs and 108 QC-passed variants in ABs were included in the final association analyses. Single-site association analysis of SNPs with MAF>1% revealed 20 variants in NHWs and 24 variants in ABs showing evidence of association with at least one lipid trait, including several variants exhibiting independent associations from the established APOE polymorphism even after multiple-testing correction. Overall, our study has confirmed known associations and also identified novel associations in this genomic region with various lipid traits. Our data also support the contribution of both common and uncommon/rare variation in this gene region in affecting plasma lipid profile in the general population.

Association of apolipoprotein E gene polymorphisms with blood lipids and their interaction with dietary factors

BACKGROUND

Several candidate genes have been identified in relation to lipid metabolism, and among these, lipoprotein lipase (LPL) and apolipoprotein E (APOE) gene polymorphisms are major sources of genetically determined variation in lipid concentrations. This study investigated the association of two single nucleotide polymorphisms (SNPs) at LPL, seven tagging SNPs at the APOE gene, and a common APOE haplotype (two SNPs) with blood lipids, and examined the interaction of these SNPs with dietary factors.

METHODS

The population studied for this investigation included 660 individuals from the Prevention of Cancer by Intervention with Selenium (PRECISE) study who supplied baseline data. The findings of the PRECISE study were further replicated using 1238 individuals from the Caerphilly Prospective cohort (CaPS). Dietary intake was assessed using a validated food-frequency questionnaire (FFQ) in PRECISE and a validated semi-quantitative FFQ in the CaPS. Interaction analyses were performed by including the interaction term in the linear regression model adjusted for age, body mass index, sex and country.

RESULTS

There was no association between dietary factors and blood lipids after Bonferroni correction and adjustment for confounding factors in either cohort. In the PRECISE study, after correction for multiple testing, there was a statistically significant association of the APOE haplotype (rs7412 and rs429358; E2, E3, and E4) and APOE tagSNP rs445925 with total cholesterol (P = 4 × 10^- 4 and P = 0.003, respectively). Carriers of the E2 allele had lower total cholesterol concentration (5.54 ± 0.97 mmol/L) than those with the E3 (5.98 ± 1.05 mmol/L) (P = 0.001) and E4 (6.09 ± 1.06 mmol/L) (P = 2 × 10^- 4) alleles. The association of APOE haplotype (E2, E3, and E4) and APOE SNP rs445925 with total cholesterol (P = 2 × 10^- 6 and P = 3 × 10^- 4, respectively) was further replicated in the CaPS. Additionally, significant association was found between APOE haplotype and APOE SNP rs445925 with low density lipoprotein cholesterol in CaPS (P = 4 × 10^- 4 and P = 0.001, respectively). After Bonferroni correction, none of the cohorts showed a statistically significant SNP-diet interaction on lipid outcomes.

CONCLUSION

In summary, our findings from the two cohorts confirm that genetic variations at the APOE locus influence plasma total cholesterol concentrations, however, the gene-diet interactions on lipids require further investigation in larger cohorts.

Classical rather than genetic risk factors account for high cardiovascular disease prevalence in Lithuania: A cross-sectional population study

PURPOSE

Cardiovascular disease (CVD) mortality accounts for 54% of all deaths in Lithuania, making it the highest among all of the European Union countries. We evaluated the prevalence of several CVD risk factors, including lifestyle, blood biochemistry and genetic predisposition to determine the reasons behind significantly increased CVD prevalence in Lithuania.

MATERIALS AND METHODS

In total 435 volunteers of Lithuanian ethnicity and stable geographic settlement for 3 generations, had their anthropometric, biochemical and behavioural risk factors measured. A randomly selected sample of 166 volunteers had their 60 CVD risk alleles genotyped. The prevalence of risk alleles and cumulative CVD genetic risk score were compared with population of North-West European origin (CEU) using data from the phase 3 HapMap project.

RESULTS

CVD was present in 33.8% of study volunteers, 84% of participants consumed alcohol, 21% were current smokers and only 30% of participants engaged in higher levels of physical activity. Also, the average BMI (males 28.3±4.3kg/m², females 27.3±5.0kg/m²), total cholesterol (males 6.1±1.2mmol/L, females 6.2±1.0mmol/L) and LDL-cholesterol (males 4.1±1.1mmol/L, females 4.1±1.0mmol/L) were above the normal values. The cumulative genetic susceptibility to develop CVD in Lithuanians was only 1.4% higher than in CEU population.

CONCLUSIONS

High BMI and poor population plasma lipid profile are the major contributing factors to high CVD mortality and morbidity in Lithuania. Smoking, alcohol consumption and preliminary genetic predisposition results do not explain the difference in CVD mortality between the Lithuanian and wider European populations. CVD prevention programmes in Lithuania should primarily focus on weight loss and improving blood lipid control.

Apolipoprotein E Gene Variants and Risk of Coronary Heart Disease: A Meta-Analysis

Objectives. Apo E genes involved in lipoprotein synthesis and metabolism are considered one of the candidates to CHD. However, the results remain conflicting. Methods. We performed this meta-analysis based on 30 published studies including 11,804 CHD patients and 17,713 controls. Results. Compared with the wild genotype E3/3, the variant genotypes ApoEE3/4 and E4/4 were associated with 22% and 45% increased risk of CHD, respectively (E3/4 versus E3/3: OR = 1.22, 95% CI = 1.15–1.29; E4/4 versus E3/3: OR = 1.45, 95% CI = 1.23–1.71). Besides, compared with ε3 allele, carriers with the ε4 allele had a 46% increased risk of CHD (OR = 1.46, 95% CI = 1.28–1.66), while the ε2 had no significantly decreased risk of CHD. In the subgroup analysis by ethnicity, ε4 had a 25% increased risk of CHD in Caucasians (OR = 1.25, 95% CI = 1.11–1.41), and the effects were more evident in Mongolians (OR = 2.29, 95% CI = 1.89–2.77). The ε2 allele had a decreased risk of CHD in Caucasians (OR = 0.84, 95% CI = 0.74–0.96), but not in Mongolians. Conclusions. The analysis suggested that ApoEε4 mutation was associated with the increased risk of CHD, while ApoEε2 allele had a decreased risk of CHD just in Caucasians.

Joint analysis of multiple blood pressure phenotypes in GAW19 data by using a multivariate rare-variant association test

INTRODUCTION

Large-scale sequencing studies often measure many related phenotypes in addition to the genetic variants. Joint analysis of multiple phenotypes in genetic association studies may increase power to detect disease-associated loci.

METHODS

We apply a recently developed multivariate rare-variant association test to the Genetic Analysis Workshop 19 data in order to test associations between genetic variants and multiple blood pressure phenotypes simultaneously. We also compare this multivariate test with a widely used univariate test that analyzes phenotypes separately.

RESULTS

The multivariate test identified 2 genetic variants that have been previously reported as associated with hypertension or coronary artery disease. In addition, our region-based analyses also show that the multivariate test tends to give smaller p values than the univariate test.

CONCLUSIONS

Hence, the multivariate test has potential to improve test power, especially when multiple phenotypes are correlated.

Genetic loci associated with ideal cardiovascular health: A meta-analysis of genome-wide association studies

BACKGROUND

Multiple genetic loci are associated with clinical cardiovascular (CV) disease and individual CV risk factors. Individuals with ideal levels of all major CV risk factors have very low risk for CV disease morbidity or mortality. Ideal levels of risk factors can be attained by lifestyle modifications; however, little is known about gene variants associated with ideal CV health. Our objective was to carry out a genome-wide association study on the trait.

METHODS AND RESULTS

We examined 2 dichotomous phenotypes of ideal CV health-clinical (untreated cholesterol <200 mg/dL, untreated blood pressure <120/<80, not diabetic) and clinical+behavioral (clinical plus: not a current smoker, body mass index <25 kg/m(2))-among white participants aged 50±5 years. We performed a meta-analysis of 4 genome-wide association studies (total n=11,708) from the MESA, CARDIA, ARIC, and Framingham Heart Study cohorts. We identified a single-nucleotide polymorphism (rs445925) in the APOC1/APOE region that was associated with clinical ideal CV health at genome-wide level of significance (P<2.0 × 10(-9)). The significance of this region was validated using exome chip genotyping. The association with ideal CV health was attenuated after adjusting for low-density lipoprotein cholesterol.

CONCLUSION

A common single-nucleotide polymorphism in the APOC1/APOE region, previously found to be associated with protective levels of cholesterol and lower CV risk, may be associated with ideal health. In future replication studies, larger sample sizes may be needed to detect loci with more modest effects on ideal CV health. In addition to the important impact of lifestyle modifications, we have identified evidence for gene variation that plays a role in ideal CV health.

Update of the effect estimates for common variants associated with carotid intima media thickness within four independent samples: The Bonn IMT Family Study, the Heinz Nixdorf Recall Study, the SAPHIR Study and the Bruneck Study

Carotid intima media thickness (cIMT) is a marker for subclinical atherosclerosis. The most recent genome-wide association meta-analysis (GWAMA) from the CHARGE consortium identified four genomic regions showing either significant (ZHX2, APOC1, PINX1) or suggestive evidence (SLC17A4) for an association. Here we assess these four cIMT loci in a pooled analysis of four independent studies including 5446 individuals by providing updated unbiased effect estimates of the cIMT association signals. The pooled estimates of our four independent samples pointed in the same direction and were similar to those of the GWAMA. When updating the independent second stage replication results from the earlier CHARGE GWAMA by our estimates, effect size estimates were closer to those of the original CHARGE discovery. A fine-mapping approach within a ±50 kb region around each lead SNP from CHARGE revealed 27 variants with larger estimated effect sizes than the lead SNPs but only three of them showed a r(2) > 0.40 with these respective lead SNPs from CHARGE. Some variants are located within potential functional loci.

Comparative physiogenomic analyses of weight loss in response to 2 modes of bariatric surgery: demonstration with candidate neuropsychiatric and cardiometabolic genes

BACKGROUND

Surgical weight loss response is variable, with suboptimal outcomes in some patients. We hypothesized that genetic biomarkers may be related to weight change.

METHODS

We tested 330 single nucleotide polymorphisms (SNPs) in genes relevant to metabolic regulation in 161 patients whose decrease in body mass index (BMI), 1 year after laparoscopic adjustable gastric banding (LAGB) or Roux-en-Y gastric bypass (RYGB), was small (lowest quartile response) or large (highest quartile response). LAGB patients whose BMI decreased≤4.7 or≥10.2 units comprised groups I (n = 43) and II (n = 40), respectively. RYGB patients whose BMI decreased≤13.6 or≥19.8 units comprised groups III (n = 39) and IV (n = 39), respectively. Within each surgery, SNPs with large differences in reference allele frequency (z score>2, corresponding to values displaced 2 standard deviations [SD] from the mean for all SNPs) in low versus high quartiles, were identified. We compared reference allele frequencies, within surgical procedure, using the χ(2) test (using Bonferroni correction for multiple testing).

RESULTS

The mean percent excess weight losses (±SD) corresponding to groups I, II, III, and IV were: 16 (±12), 64 (±30), 55 (±16), and 75 (±17), respectively. SNPs with z score>2 were identified in genes involved in LAGB response, lipid metabolic regulation (APOE, rs439401; APOC4, rs2288911), neural processes (DRD3, rs167771; HTR3 B, rs3758987), and xeno- or endobiotic metabolism (CYP3 A4, rs12333983); and for RYGB response, in lipid transport (SCARB1, rs10846744), folate metabolism (MTHFR, rs2066470), regulation of glycolysis in immune cells (HIF1 A, rs1951795), vitamin K cycling (VKORC1, rs2359612), and xeno- or endobiotic metabolism (CYP3 A4, rs2242480). For LAGB response, APOE SNP frequencies were significantly different.

CONCLUSIONS

With further validation, information derived from patient DNA may be useful to predict surgical weight loss outcomes and guide selection of surgical approach.

Genetic Contribution of Variants near SORT1 and APOE on LDL Cholesterol Independent of Obesity in Children

Objective

To assess potential effects of variants in six lipid modulating genes (SORT1, HMGCR, MLXIPL, FADS2, APOE and MAFB) on early development of dyslipidemia independent of the degree of obesity in children, we investigated their association with total (TC), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) cholesterol and triglyceride (TG) levels in 594 children. Furthermore, we evaluated the expression profile of the candidate genes during human adipocyte differentiation.

Results

Expression of selected genes increased 10¹ to >10⁴ fold during human adipocyte differentiation, suggesting a potential link with adipogenesis. In genetic association studies adjusted for age, BMI SDS and sex, we identified significant associations for rs599839 near SORT1 with TC and LDL-C and for rs4420638 near APOE with TC and LDL-C. We performed Bayesian modelling of the combined lipid phenotype of HDL-C, LDL-C and TG to identify potentially causal polygenic effects on this multi-dimensional phenotype and considering obesity, age and sex as a-priori modulating factors. This analysis confirmed that rs599839 and rs4420638 affect LDL-C.

Conclusion

We show that lipid modulating genes are dynamically regulated during adipogenesis and that variants near SORT1 and APOE influence lipid levels independent of obesity in children. Bayesian modelling suggests causal effects of these variants.

The association of APOC4 polymorphisms with premature coronary artery disease in a Chinese Han population

Background

Hypercholesterolemia arising from abnormal lipid metabolism is one of the critical risk factors for coronary artery disease (CAD), however the roles of genetic variants in lipid metabolism-related genes on premature CAD (≤60 years old) development still require further investigation. We herein genotyped four single nucleotide polymorphisms (SNPs) in lipid metabolism-related genes (rs1132899 and rs5167 in APOC4, rs1801693 and rs7765781 in LPA), aimed to shed light on the influence of these SNPs on individual susceptibility to early-onset CAD.

Methods

Genotyping of the four SNPs (rs1132899, rs5167, rs1801693 and rs7765781) was performed in 224 premature CAD cases and 297 control subjects (≤60 years old) using polymerase chain reaction-ligation detection reaction (PCR–LDR) method. The association of these SNPs with premature CAD was performed with SPSS software.

Results

Multivariate logistic regression analysis showed that C allele (OR = 1.50, P = 0.027) and CC genotype (OR = 2.84, P = 0.022) of APOC4 rs1132899 were associated with increased premature CAD risk, while the other three SNPs had no significant effect. Further stratified analysis uncovered a more evident association with the risk of premature CAD among male subjects (C allele, OR = 1.65, and CC genotype, OR = 3.33).

Conclusions

Our data provides the first evidence that APOC4 rs1132899 polymorphism was associated with an increased risk of premature CAD in Chinese subjects, and the association was more significant among male subjects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0065-7) contains supplementary material, which is available to authorized users.

Comprehensive evaluation of the association of APOE genetic variation with plasma lipoprotein traits in U.S. whites and African blacks

Although common APOE genetic variation has a major influence on plasma LDL-cholesterol, its role in affecting HDL-cholesterol and triglycerides is not well established. Recent genome-wide association studies suggest that APOE also affects plasma variation in HDL-cholesterol and triglycerides. It is thus important to resequence the APOE gene to identify both common and uncommon variants that affect plasma lipid profile. Here, we have sequenced the APOE gene in 190 subjects with extreme HDL-cholesterol levels selected from two well-defined epidemiological samples of U.S. non-Hispanic Whites (NHWs) and African Blacks followed by genotyping of identified variants in the entire datasets (623 NHWs, 788 African Blacks) and association analyses with major lipid traits. We identified a total of 40 sequence variants, of which 10 are novel. A total of 32 variants, including common tagSNPs (≥5% frequency) and all uncommon variants (<5% frequency) were successfully genotyped and considered for genotype-phenotype associations. Other than the established associations of APOE*2 and APOE*4 with LDL-cholesterol, we have identified additional independent associations with LDL-cholesterol. We have also identified multiple associations of uncommon and common APOE variants with HDL-cholesterol and triglycerides. Our comprehensive sequencing and genotype-phenotype analyses indicate that APOE genetic variation impacts HDL-cholesterol and triglycerides in addition to affecting LDL-cholesterol.

Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins

Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response.

Contribution of genetic background and antiretroviral therapy to body fat changes in antiretroviral-naive HIV-infected adults

OBJECTIVES

To evaluate the association of host genetics with changes in limb or trunk fat in a group of antiretroviral therapy (ART)-naive HIV-infected patients prospectively followed up according to the initiation and the type of ART.

METHODS

Fifty single nucleotide polymorphisms (SNPs) in 26 genes, associated with obesity, insulin resistance, lipid metabolism or lipodystrophy in previously published genetic studies, were assessed in ART-naive HIV-infected Caucasian patients divided into three groups: 24 (27%) did not start ART, 29 (32.6%) received zidovudine or stavudine and 36 (40.4%) received neither zidovudine nor stavudine in their initial regimen. Patients underwent body fat measurements (using dual-energy X-ray absorptiometry) at baseline and Month 12. A multivariate model using backward stepwise elimination was used to assess the influence of SNPs and baseline levels of non-genetic covariates on changes in limb or trunk fat.

RESULTS

The baseline characteristics were: 73% men, 17% coinfected with hepatitis C virus and/or hepatitis B virus, median age 37 years, median CD4+ T cell count 228/mm(3), median HIV-RNA 5.2 log copies/mL, median plasma glucose 85 mg/dL, median plasma insulin 9.1 IU/mL, median limb fat 5.6 kg and median trunk fat 7.0 kg. There were no baseline differences among the three groups except for the CD4+ T cell count. The decrease in limb fat was greater in the no-ART group relative to the other two groups (P < 0.05). The multivariate model showed associations of rs1801278 in IRS1 (P = 0.029, OR = 0.13), baseline viral load (P = 0.006; OR = 4.453) and baseline glucose levels (P = 0.008, OR = 0.926) with loss of limb fat, and rs2228671 in LDLR (P = 0.012, OR = 0.108), rs405509 in APOE (P = 0.048, OR = 0.205), baseline viral load (P = 0.005, OR = 0.186) and baseline CD4+ T cell count (P = 0.01, OR = 1.008) with gain of trunk fat.

CONCLUSIONS

Specific polymorphisms in IRS1 (limb fat loss) and LDLR and APOE (trunk fat gain) were identified as independent markers of fat changes irrespective of the initiation of ART and the type of ART and deserve further validation.

Analysis of the placental tissue transcriptome of normal and preeclampsia complicated pregnancies

Preeclampsia is one of the most severe gestational complications which is one of the leading causes of maternal and perinatal morbidity and mortality. A growth in the incidence of severe and combined forms of the pathology has been observed in recent years. According to modern concepts, inadequate cytotrophoblast invasion into the spiral arteries of the uterus and development of the ischemia-reperfusion syndrome in the placental tissue play the leading role in the development of preeclampsia, which is characterized by multipleorgan failure. In this regard, our work was aimed at studying the patterns of placental tissue transcriptome that are specific to females with PE and with physiological pregnancy, as well as identifying the potential promising biomarkers and molecular mechanisms of this pathology. We have identified 63 genes whose expression proved to differ significantly in the placental tissue of females with PE and with physiological pregnancy. A cluster of differentially expressed genes (DEG) whose expression level is increased in patients with preeclampsia includes not only the known candidate genes that have been identified in many other genome-wide studies (e.g., LEP, BHLHB2, SIGLEC6, RDH13, BCL6), but also new genes (ANKRD37, SYDE1, CYBA, ITGB2, etc.), which can be considered as new biological markers of preeclampsia and are of further interest. The results of a functional annotation of DEG show that the development of preeclampsia may be related to a stress response, immune processes, the regulation of cell-cell interactions, intracellular signaling cascades, etc. In addition, the features of the differential gene expression depending on preeclampsia severity were revealed. We have found evidence of the important role of the molecular mechanisms responsible for the failure of immunological tolerance and initiation of the pro-inflammatory cascade in the development of severe preeclampsia. The results obtained elaborate the concept of the pathophysiology of preeclampsia and contain the information necessary to work out measures for targeted therapy of this disease. ;

Genetic architecture of carotid artery intima-media thickness in Mexican Americans

BACKGROUND- Intima-media thickness (IMT) of the common and internal carotid arteries is an established surrogate for atherosclerosis and predicts risk of stroke and myocardial infarction. Often IMT is measured as the average of these 2 arteries; yet, they are believed to result from separate biological mechanisms. The aim of this study was to conduct a family-based genome-wide association study (GWAS) for IMT to identify polymorphisms influencing IMT and to determine if distinct carotid artery segments are influenced by different genetic components. METHODS AND RESULTS- IMT for the common and internal carotid arteries was determined through B-mode ultrasound in 772 Mexican Americans from the San Antonio Family Heart Study. A GWAS using 931219 single-nucleotide polymorphisms was undertaken with 6 internal and common carotid artery IMT phenotypes using an additive measured genotype model. The most robust association detected was for 2 single-nucleotide polymorphisms (rs16983261, rs6113474; P=1.60e(-7)) in complete linkage disequilibrium on chromosome 20p11 for the internal carotid artery near wall, next to the gene PAX1. We also replicated previously reported GWAS regions on chromosomes 19q13 and 7q22. We found no overlapping associations between internal and common carotid artery phenotypes at P<5.0e(-6). The genetic correlation between the 2 carotid IMT arterial segments was 0.51. CONCLUSIONS- This study represents the first large-scale GWAS of carotid IMT in a non-European population and identified several novel loci. We do not detect any shared GWAS signals between common and internal carotid arterial segments, but the moderate genetic correlation implies both common and unique genetic components.

Chronic family stress moderates the association between a TOMM40 variant and triglyceride levels in two independent Caucasian samples

TOMM40 SNP rs157580 has been associated with triglyceride levels in genome-wide association studies (GWAS). Chronic caregiving stress moderates the association between triglyceride levels and a nearby SNP rs439401 that is associated with triglyceride levels in GWAS. Here, we report data from two independent Caucasian samples (242 U.S. women and men; 466 Danish men) testing the hypothesis that chronic family stress also moderates the association between rs157580 and triglyceride levels. The interaction of rs157580 and family stress in predicting triglyceride levels was statistically significant in the U.S. sample (p=0.004) and marginally significant (p=0.075) in the Danish sample. The G allele of rs157580 was associated with increased triglyceride levels among family stressed cases in both samples compared with A/A cases, but not among controls. Chronic family stress moderates the association of rs157580 variants with triglyceride levels and should be taken into account for disease risk assessment and potential intervention.

Genome-wide analysis of LXRα activation reveals new transcriptional networks in human atherosclerotic foam cells

Increased physiological levels of oxysterols are major risk factors for developing atherosclerosis and cardiovascular disease. Lipid-loaded macrophages, termed foam cells, are important during the early development of atherosclerotic plaques. To pursue the hypothesis that ligand-based modulation of the nuclear receptor LXRα is crucial for cell homeostasis during atherosclerotic processes, we analysed genome-wide the action of LXRα in foam cells and macrophages. By integrating chromatin immunoprecipitation-sequencing (ChIP-seq) and gene expression profile analyses, we generated a highly stringent set of 186 LXRα target genes. Treatment with the nanomolar-binding ligand T0901317 and subsequent auto-regulatory LXRα activation resulted in sequence-dependent sharpening of the genome-binding patterns of LXRα. LXRα-binding loci that correlated with differential gene expression revealed 32 novel target genes with potential beneficial effects, which in part explained the implications of disease-associated genetic variation data. These observations identified highly integrated LXRα ligand-dependent transcriptional networks, including the APOE/C1/C4/C2-gene cluster, which contribute to the reversal of cholesterol efflux and the dampening of inflammation processes in foam cells to prevent atherogenesis.

A comprehensive survey of copy number variation in 18 diverse pig populations and identification of candidate copy number variable genes associated with complex traits

Background

Copy number variation (CNV) is a major source of structural variants and has been commonly identified in mammalian genome. It is associated with gene expression and may present a major genetic component of phenotypic diversity. Unlike many other mammalian genomes where CNVs have been well annotated, studies of porcine CNV in diverse breeds are still limited.

Result

Here we used Porcine SNP60 BeadChip and PennCNV algorithm to identify 1,315 putative CNVs belonging to 565 CNV regions (CNVRs) in 1,693 pigs from 18 diverse populations. Total 538 out of 683 CNVs identified in a White Duroc × Erhualian F₂ population fit Mendelian transmission and 6 out of 7 randomly selected CNVRs were confirmed by quantitative real time PCR. CNVRs were non-randomly distributed in the pig genome. Several CNV hotspots were found on pig chromosomes 6, 11, 13, 14 and 17. CNV numbers differ greatly among different pig populations. The Duroc pigs were identified to have the most number of CNVs per individual. Among 1,765 transcripts located within the CNVRs, 634 genes have been reported to be copy number variable genes in the human genome. By integrating analysis of QTL mapping, CNVRs and the description of phenotypes in knockout mice, we identified 7 copy number variable genes as candidate genes for phenotypes related to carcass length, backfat thickness, abdominal fat weight, length of scapular, intermuscle fat content of logissimus muscle, body weight at 240 day, glycolytic potential of logissimus muscle, mean corpuscular hemoglobin, mean corpuscular volume and humerus diameter.

Conclusion

We revealed the distribution of the unprecedented number of 565 CNVRs in pig genome and investigated copy number variable genes as the possible candidate genes for phenotypic traits. These findings give novel insights into porcine CNVs and provide resources to facilitate the identification of trait-related CNVs.

Large-scale association analysis identifies new risk loci for coronary artery disease

Coronary artery disease (CAD) is the commonest cause of death. Here, we report an association analysis in 63,746 CAD cases and 130,681 controls identifying 15 loci reaching genome-wide significance, taking the number of susceptibility loci for CAD to 46, and a further 104 independent variants (r(2) < 0.2) strongly associated with CAD at a 5% false discovery rate (FDR). Together, these variants explain approximately 10.6% of CAD heritability. Of the 46 genome-wide significant lead SNPs, 12 show a significant association with a lipid trait, and 5 show a significant association with blood pressure, but none is significantly associated with diabetes. Network analysis with 233 candidate genes (loci at 10% FDR) generated 5 interaction networks comprising 85% of these putative genes involved in CAD. The four most significant pathways mapping to these networks are linked to lipid metabolism and inflammation, underscoring the causal role of these activities in the genetic etiology of CAD. Our study provides insights into the genetic basis of CAD and identifies key biological pathways.

Connections between apolipoprotein E genotypes and the development of cardiovascular diseases

Elevated plasma lipid level is one of the main risk factors for cardiovascular diseases, which are considered to be pimary causes of death. Apolipoprotein E plays a part in the lipid transport in the blood, thus polimophisms of that affect the lipid composition of the plasma. The three most common alleles of apolipoprotein E are e2, e3, e4. Out of the two non-wild type alleles, the e2 and e4, the latter was shown to play a role in the development of cardiovascular diseases and Alzheimer’s disease. Some studies mention the e2/e2 homozygote genotype as one of the causes of hyperlipoproteinemia type III. Besides lipid metabolism, apolipoprotein E also influences the manifestation of cardiovascular diseases through other biochemical pathways, therefore it is essential to explore the molecular background of these metabolic pathways. Orv. Hetil., 2012, 153, 2070–2076.

Impact of common genetic variation on response to simvastatin therapy among 18 705 participants in the Heart Protection Study

Aims

Statins reduce LDL cholesterol (LDL-C) and the risk of vascular events, but it remains uncertain whether there is clinically relevant genetic variation in their efficacy. This study of 18 705 individuals aims to identify genetic variants related to the lipid response to simvastatin and assess their impact on vascular risk response.

Methods and results

A genome-wide study of the LDL-C and apolipoprotein B (ApoB) response to 40 mg simvastatin daily was performed in 3895 participants in the Heart Protection Study, and the nine strongest associations were tested in 14 810 additional participants. Selected candidate genes were also tested in up to 18 705 individuals. There was 90% power to detect differences of 2.5% in LDL-C response (e.g. 42.5 vs. 40% reduction) in the genome-wide study and of 1% in the candidate gene study. None of the associations from the genome-wide study was replicated, and nor were significant associations found for 26 of 36 candidates tested. Novel lipid response associations with variants in LPA, CELSR2/PSRC1/SORT1, and ABCC2 were found, as well as confirmatory evidence for published associations in LPA, APOE, and SLCO1B1. The largest and most significant effects were with LPA and APOE, but were only 2–3% per allele. Reductions in the risk of major vascular events during 5 years of statin therapy among 18 705 high-risk patients did not differ significantly across genotypes associated with the lipid response.

Conclusions

Common genetic variants do not appear to alter the lipid response to statin therapy by more than a few per cent, and there were similar large reductions in vascular risk with simvastatin irrespective of genotypes associated with the lipid response to simvastatin. Consequently, their value for informing clinical decisions related to maximizing statin efficacy appears to be limited.

High density GWAS for LDL cholesterol in African Americans using electronic medical records reveals a strong protective variant in APOE

Only one low-density lipoprotein cholesterol (LDL-C) genome-wide association study (GWAS) has been previously reported in -African Americans. We performed a GWAS of LDL-C in African Americans using data extracted from electronic medical records (EMR) in the eMERGE network. African Americans were genotyped on the Illumina 1M chip. All LDL-C measurements, prescriptions, and diagnoses of concomitant disease were extracted from EMR. We created two analytic datasets; one dataset having median LDL-C calculated after the exclusion of some lab values based on comorbidities and medication (n= 618) and another dataset having median LDL-C calculated without any exclusions (n= 1,249). SNP rs7412 in APOE was strongly associated with LDL-C in both datasets (p < 5 × 10(-8) ). In the dataset with exclusions, a decrease of 20.0 mg/dL per minor allele was observed. The effect size was attenuated (12.3 mg/dL) in the dataset without any lab values excluded. Although other signals in APOE have been detected in previous GWAS, this large and important SNP association has not been well detected in large GWAS because rs7412 was not included on many genotyping arrays. Use of median LDL-C extracted from EMR after exclusions for medications and comorbidities increased the percentage of trait variance explained by genetic variation.

Low-density lipoprotein cholesterol, apolipoprotein B, and risk of coronary heart disease: from familial hyperlipidemia to genomics

Coronary heart disease (CHD) affects 17 million people in the United States and accounts for over a million hospital stays each year. Technological advances, especially in genetics and genomics, have changed our understanding of the risk factors for developing CHD. The purpose of this article is to review low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apo B), and risk of CHD. The article focuses on five topics: (1) a description of lipoprotein classes, normal lipoprotein metabolism, and the biological mechanism of atherosclerosis; (2) a review of selected epidemiologic and clinical trial studies examining the associations between elevated LDL-C and apo B with CHD; (3) a brief review of the familial forms of hyperlipidemia; (4) a description of variants in genes that have been associated with higher LDL-C levels in candidate gene studies and genome-wide association studies (GWAS); and (5) nursing implications, including a discussion on how genetic tests are evaluated and the current clinical utility and validity of genetic tests for CHD.

Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR

Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.

Genome-wide association study of genetic determinants of LDL-c response to atorvastatin therapy: importance of Lp(a)

We carried out a genome-wide association study (GWAS) of LDL-c response to statin using data from participants in the Collaborative Atorvastatin Diabetes Study (CARDS; n = 1,156), the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT; n = 895), and the observational phase of ASCOT (n = 651), all of whom were prescribed atorvastatin 10 mg. Following genome-wide imputation, we combined data from the three studies in a meta-analysis. We found associations of LDL-c response to atorvastatin that reached genome-wide significance at rs10455872 (P = 6.13 × 10(-9)) within the LPA gene and at two single nucleotide polymorphisms (SNP) within the APOE region (rs445925; P = 2.22 × 10(-16) and rs4420638; P = 1.01 × 10(-11)) that are proxies for the ε2 and ε4 variants, respectively, in APOE. The novel association with the LPA SNP was replicated in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) trial (P = 0.009). Using CARDS data, we further showed that atorvastatin therapy did not alter lipoprotein(a) [Lp(a)] and that Lp(a) levels accounted for all of the associations of SNPs in the LPA gene and the apparent LDL-c response levels. However, statin therapy had a similar effect in reducing cardiovascular disease (CVD) in patients in the top quartile for serum Lp(a) levels (HR = 0.60) compared with those in the lower three quartiles (HR = 0.66; P = 0.8 for interaction). The data emphasize that high Lp(a) levels affect the measurement of LDL-c and the clinical estimation of LDL-c response. Therefore, an apparently lower LDL-c response to statin therapy may indicate a need for measurement of Lp(a). However, statin therapy seems beneficial even in those with high Lp(a).

Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk

This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.

Genetic determinants of LDL, lipoprotein(a), triglyceride-rich lipoproteins and HDL: concordance and discordance with cardiovascular disease risk

PURPOSE OF REVIEW

To evaluate whether new and known genetic determinants of plasma levels of LDL cholesterol, lipoprotein(a), triglyceride-rich lipoproteins, and HDL cholesterol associate with the risk of cardiovascular disease expected from the effect on lipoprotein levels. Concordance or discordance of such genetic determinants with cardiovascular disease risk will either favor or disfavor that these lipoproteins are causally related to cardiovascular disease.

RECENT FINDINGS

Evidence for concordance or discordance with cardiovascular disease risk has come from Mendelian randomization studies, whereas indirect evidence also has emerged from genome-wide and candidate gene association studies. The major limitations of studies of genetic variation and concordance or discordance with cardiovascular disease are pleiotropic effects of the variants studied, and/or lack of sufficient statistical power of the majority of studies to firmly demonstrate a positive association, or even more difficult, to exclude an association.

SUMMARY

New and known genetic determinants of plasma levels of LDL cholesterol, lipoprotein(a), and triglyceride-rich lipoproteins are concordant with both the magnitude and direction of the expected risk of cardiovascular disease, whereas this is unclear for HDL cholesterol. The data are compatible with cardiovascular disease causality for the three former lipoprotein classes, but not for HDL cholesterol.

Haplotype and genotype effects of the F7 gene on circulating factor VII, coagulation activation markers and incident coronary heart disease in UK men

BACKGROUND

Evidence for the associations of single nucleotide polymorphisms (SNPs) in the F7 gene and factor (F)VII levels and with risk of coronary heart disease (CHD) is inconsistent. We examined whether F7 tagging SNPs (tSNPs) and haplotypes were associated with FVII levels, coagulation activation markers (CAMs) and CHD risk in two cohorts of UK men.

METHODS

Genotypes for eight SNPs and baseline levels of FVIIc, FVIIag and CAMs (including FVIIa) were determined in 2773 healthy men from the Second Northwick Park Heart Study (NPHS-II). A second cohort, Whitehall II study (WH-II, n = 4055), was used for replication analysis of FVIIc levels and CHD risk.

RESULTS

In NPHS-II the minor alleles of three SNPs (rs555212, rs762635 and rs510317; haplotype H2) were associated with higher levels of FVIIag, FVIIc and FVIIa, whereas the minor allele for two SNPs (I/D323 and rs6046; haplotype H5) was associated with lower levels. Adjusted for classic risk factors, H2 carriers had a CHD hazard ratio of 1.34 [95% confidence interval (CI): 1.12-1.59; independent of FVIIc], whereas H5 carriers had a CHD risk of 1.29 (95% CI: 1.01-1.56; not independent of FVIIc) and significantly lower CAMs. Effects of haplotypes on FVIIc levels were replicated in WH-II, as was the association of H5 with higher CHD risk [pooled-estimate odds ratio (OR) 1.16 (1.00-1.36), P = 0.05], but surprisingly, H2 exhibited a reduced risk for CHD.

CONCLUSION

 tSNPs in the F7 gene strongly influence FVII levels. The haplotype associated with low FVIIc level, with particularly reduced functional activity, was consistently associated with increased risk for CHD, whereas the haplotype associated with high FVIIc level was not.