Apolipoprotein E polymorphism in a Moroccan population: allele frequency and relation to plasma lipid concentrations

To date, no data are available on relationship between apolipoprotein E (apo E) polymorphism and lipid levels in Moroccan population. The present work reports an apo E polymorphism repartition in Moroccan population and relationship between this polymorphism and the levels of plasma cholesterol, triglycerides, apo A1, B and E. Blood samples from 168 healthy Moroccan individuals from Rabat area (90 men and 78 women), aged from 20 to 50 years (32 9 years), were analysed for serum apo E, A1 and B, triglycerides, and total cholesterol. In parallel, genotyping by means of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) was performed. The apo E allelic frequencies were 11% for epsilon4, 84% for epsilon3 and 5% for epsilon2. There were correlation between apo E alleles and serum lipid concentrations, E2/E3 carriers had significantly higher level of apo E than E3/E3, and E4/E3 carriers had significantly higher total cholesterol apo B and triglycerides than E3/E3 and E2/E3 carriers. The total cholesterol and apo B concentrations are significantly higher in women than in men but the triglycerides are lower. The apo A1 concentration is independent of both sex and apo E genotype. Thus, the results demonstrate an influence of apo E alleles on serum cholesterol, triglycerides, apo E and apo B concentrations among healthy Moroccan.     

Apolipoprotein E polymorphism in the Greek population

The APOE gene is located on chromosome 19, and the three common alleles are designated ε2, ε3, and ε4. The ε4 allele is associated with increased plasma cholesterol, atherosclerosis and cardiovascular disease, Alzheimer's disease, and decreased longevity. The objective of the present study was to estimate the distribution of APOE alleles in the Greek population by DNA analysis. The material consisted of 216 voluntary, healthy Greek blood donors (146 males/70 females). The APOE allele frequencies were ε2: 5.3%, ε3: 88.2%, ε4: 6.5%. The ε4 allele frequency of 6.5% in the Greek population is, together with the frequency in the Chinese population, among the lowest in the world.     

载脂蛋白E的遗传多态性与血浆脂质

本文采用快速薄层平板等电聚焦电泳加敏感的银染技术,对南京地区63名正常人、70名非FH高脂血症患者,11名FH患者Apo-E表型、等位基因频率及血脂水平进行测定,发现正常人ε3基因频率高于、ε4基因频率低于正常高加索人,这种特征,可能与我国人群CAD发病率较西方人群为低有关。血脂测定表明,Apo-E3/2型TG、VLDL-C、VLDL-TG和VLDL-C/VLDL-TG水平升高,TC、LDL-C和HDL-C则降低,Apo-E4/3型相反。我们还发现,Ⅱb型HLPε4基因频率最高,Ⅲ型HLPε2基因频率最高。看来,ε2基因具有升高TG丰富脂蛋白、降低ch丰富脂蛋白的作用,而ε4基因作用相反。测定Apo-E表型对预测冠心病危险性可能有作用。FH患者,ε3基因频率明显低于正常人,ε2和ε4频率升高,这是否因为多个基因间相互作用,尚待进一步研究。     

Apolipoprotein E allelic frequency in elderly smokers

Susceptibility genes for human diseases (e.g., cancer and atherosclerosis) increase disease risk by altering the metabolic activation of exogenous (e.g., carcinogens) and endogenous (e.g., cholesterol) compounds. The function of these genes, and subsequent risk, can be adversely affected by polymorphisms. This study tests the hypothesis that if specific genetic polymorphisms are related to mortality, then in elderly heavy smokers, there should be a decreased frequency of “at risk” alleles and an increased frequency of “protective” alleles, i.e., a survival effect. One such potential polymorphism is in the apolipoprotein E (apoE) gene, which is involved in cholesterol metabolism, where the ϵ4 allele is associated with an increased risk of coronary artery disease and is under represented in elderly populations. In this study, ApoE variant alleles were determined in 81 living, elderly current smokers (mean age: 72.5; range: 65–94; mean pack-years: 78; range: 13–192) and in 82 younger autopsy donors (mean age: 33; range: 1–58). There was a borderline difference in the apoE 4 allelic frequencies among the groups (11% in the elderly and 18% in the comparable younger group [df = 1; χ² = 4.02; P = 0.05]). A significant difference was found for age when stratified as a continuous variable by genotype in the elderly smokers (P = 0.03; mean age for persons with and without ϵ4 was 69.9 and 73.2, respectively). Pack-years of cigarette smokers did not differ by genotype, indicating no selective effect. These results confirm earlier associations for differences in the apoE allelic frequencies in the elderly and extend it to smokers, who generally have increased mortality at younger ages. Am. J. Med. Genet. 76:32–36, 1998. © 1998 Wiley-Liss, Inc. This article is a US Government work and, as such, is in the public domain of the United States of America.     

Apolipoprotein E polymorphism and fertility: a study in pre-industrial populations

Human apolipoprotein E is the most important supplier of the cholesterol precursor for steroid hormone production in steroidogenic tissues and therefore could play a role in the regulation of steroid hormone function and influence human reproduction. This hypothesis has been confirmed by studies describing a differential fertility associated with common apolipoprotein (APOE) genotypes in two European populations. In the present investigation the impact of APOE genetic variation on fertility was studied in two Ecuadorian populations, African-Ecuadorians (57 women) and Cayapa Indians (27 women). In addition some biodemographic variables concerning women's fertility were investigated (124 African-Ecuadorian women; 40 Cayapa women) to better understand the APOE-fertility relationships in these pre-industrial populations. General fertility rates in both populations were very high (6.5 and 6.2 for the African-Ecuadorians and for the Cayapa respectively). When considering only women near the end of reproductive life (>/=40 years), a more marked difference was observed between the two groups (9.1 versus 7.7, P=0.09). In both communities, the highest number of children was found to be associated with the e*4/e*3 genotype; the e*4/e*3 genotype frequency (0.50) in the African-Ecuadorian women with 9-17 children was about three times that of the women with 0-8 children (0.14) (P=0.02). The present findings are at variance with those observed in European populations, where e*3/e*3 was the genotype associated with the highest reproductive efficiency. A possible explanation for this inconsistency could be due to the different functional properties associated with the e*3 and e*4 alleles and to genotype interactions with environmental factors including reproductive strategies.     

Apolipoprotein E polymorphism and dendritic shape in hippocampal interneurons

The apolipoprotein E genetic polymorphism exerts a well described influence on Alzheimer's disease (AD) risk, although the pathogenetic mechanism is still not clear. Increasing evidence points to a diminished neuroplasticity in apolipoprotein E varepsilon4-allele carriers. But, alternatively or additionally, developmental differences in dendritic geometry may be associated with the polymorphism. We morphometrically examined the dendritic ramification of CA1 Parvalbumin-positive GABAergic hippocampal neurons (n=571) in matched pairs of aged non-demented individuals with different apolipoprotein E genotype. We chose Parvalbumin-positive interneurons since they lack potentially confounding AD-like cytoskeletal changes. To minimize the risk of transneuronal dendritic changes due to significant deafferentation we focused on non-demented individuals. In this chosen paradigm, neither the disease-associated apolipoprotein E varepsilon4-allele nor the apolipoprotein E varepsilon2-allele had a significant impact on dendritic shape when compared to the most common allelic variant apolipoprotein E varepsilon3/3. At least with respect to the studied cell type, the data suggest that the apolipoprotein E polymorphism does not modulate the original formation of dendrites in vivo, contrary to conclusions drawn from in vitro studies on neurite outgrowth.     

The effect of apolipoprotein E polymorphism on lipid levels in Korean adults

The aim of this study was to determine the effects of polymorphisms in the apolipoprotein E gene (APOE) on lipid levels in Korean adults and to investigate the interactions between these polymorphisms and environmental factors in determining lipid levels. We performed a cross-sectional study of 1,900 subjects (668 men and 1,232 women; 45-74 yr old) in Namwon, Korea, in 2004. APOE polymorphisms were determined by polymerase chain reaction and restriction enzyme analysis. Carriers of the APOE*E2 (E2) allele had significantly lower total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations than did carriers of the APOE*E3 (E3) or APOE*E4 (E4) alleles, regardless of gender. The APOE allele type had significant effect on high-density lipoprotein cholesterol (HDL-C) and triglyceride levels in women, but not in men. The effect of APOE allele type on HDL-C levels was modified by age in women. In addition, in men, the effect of APOE allele type on triglyceride levels was modified by smoking. These findings highlight the important effect of gene-environment interactions on lipid levels.     

Apolipoprotein E polymorphism in Pick's disease and in Huntington's disease

The polymorphism of apolipoprotein E (apoE) has been recognized as a genetic risk factor in different neurodegenerative disorders, with or without tau protein- related neuropathology, but few published epidemiological data are available as concerns the association of different apoE alleles with two relatively rare forms of dementia, Pick's disease (PiD) and Huntington's disease (HD). In this study the frequency of the apoE4 allele was examined in 36 persons with histopathologically proven PiD and compared with that of the apoE genotype in 28 HD probands and 79 aged healthy controls. The E4 allele was overrepresented selectively in PiD (42%) as compared with the control population (7%). No such association was found for HD probands (9%). This finding lends further support to the hypothesis that the E4 genotype is not an Alzheimer's disease specific susceptibility factor, and that it could be present in diverse dementing disorders with tau protein related neuropathology, such as PiD.     

Apolipoprotein E polymorphism and lipid levels differ by gender and family history of diabetes: the Rancho Bernardo Study

Association between apolipoprotein E (apoE) gene polymorphism and lipid levels was studied in 164 nondiabetic first-degree relatives of persons with diabetes and 962 nondiabetic persons with no family history of diabetes. Sex-specific genotypic distribution of apoE polymorphism did not differ between persons with and without a family history of diabetes. In first-degree relatives, lipid levels did not differ among persons with apoE2 (E2/2, E2/3), apoE3/3, and apoE4 (E4/4, E3/4) after adjusting for age, waist circumference, smoking, and alcohol and estrogen use. In persons without a family history of diabetes, both men (p<0.01) and women (p<0.001) with apoE2 showed lower levels of total and low density lipoprotein cholesterol compared with persons with apoE3/3 and apoE4. In women with a family history of diabetes, persons with apoE4 had larger waist circumference (p<0.05). ApoE2 allele is associated with more favorable levels of total and low density lipoprotein cholesterol in men and women without a family history of diabetes. ApoE4 allele is associated with obesity independent of dyslipidemia in women but not men with a family history of diabetes. ApoE polymorphism is not associated with lipids in men or women with a family history of diabetes.     

Apolipoprotein E gene polymorphism in cerebrovascular disease: a case-control study

The association between apolipoprotein E (apo E) polymorphism and stroke has been controversial. So far there are no studies reported on the polymorphism of apolipoprotein E in cerebrovascular diseases in the Asian Indians. A blinded case-control study was therefore undertaken and the apo E genotypes and lipid profile of a total of 120 subjects (63 stroke patients and 57 healthy controls) were done. The frequency distribution of apo E alleles and genotypes were assessed and their relation with the occurrence of stroke in Asian Indian subjects was determined. A significantly high frequency of apo epsilon4 allele (30%) was observed in the stroke patients than the controls (11%) (p < 0.005), and patients with epsilon4 allele had a fourfold higher odds to develop stroke OR (95%CI) 4.2 (1.8-10.1) (p < 0.005). On multivariate analysis, after adjusting for age, triglycerides and hypertension, the association of epsilon4 allele with stroke was found to be no longer statistically significant, OR (95%CI) 1.2 (0.4-4.5) (p = NS). On multiple logistic regression analysis age, OR (95%CI) 1.1 (1.1-1.2) (p < 0.001), and hypertension OR (95%CI) 15.1 (2.6-89.1) (p < 0.005) were found to be independent risk factors for development of stroke. This is the first report to have examined the association of apo E gene polymorphism with stroke in the Asian Indians. This study suggests that apo epsilon4 allele, triglycerides, age and hypertension are the predictors for stroke development.     

Apolipoprotein E polymorphism, age and coronary heart disease

Plasma concentrations of lipids, lipoproteins, and apolipoproteins (apo) are established risk factors for coronary heart disease (CHD). The knowledge of lipid profile may predict the potential victims of cardiovascular disease before its initiation and progression and offer the opportunity for primary prevention. The most common apo E polymorphism has been found to influence blood lipid concentrations and its correlation with CHD has been extensively investigated in the last decade. At younger ages, death from CHD is influenced by genetic factors, while the genetic effect decreases at older ages where environmental factors may play a more prominent role. If apo E polymorphism is an important genetic factor in the pathogenesis of atherosclerosis, it could affect the age of CHD onset. This review analyses the influence of apo E polymorphism on blood lipids and CHD in respect to age.     

Influence of Apolipoprotein E polymorphism on susceptibility of Wilson disease

Wilson disease (WD) is an autosomal‐recessive disorder caused by mutations in the ATP7B gene leading to abnormal copper deposition in liver and brain. WD manifests diverse neurological and hepatic phenotypes and different age of onset, even among the siblings, with same mutational background suggesting complex nature of the disease and involvement of other candidate genes. In that context, Apolipoprotein E (APOE) and Prion Protein (PRNP) have been proposed to be potential candidates for modifying the WD phenotype and age of onset. This study aims to identify the contribution of APOE and PRNP polymorphisms on the variable phenotypic expression of Indian WD patients. A total of 171 WD patients and 291 controls from Indian population were included in this study. Two APOE cSNPs (rs429358 and rs7412) resulting in three isoforms and M129V (rs1799990) polymorphism of PRNP were examined for their association with WD and its clinical phenotypes. The APOE ?4 allele was found to be significantly overrepresented in WD patients compared to controls. However, the frequency of the APOE ?3 allele and ?3/?3 genotype was significantly higher in WD patients without cognitive behavior impairment compared to the ones with the impairment. On the contrary, the PRNP allele representing Val129 was found to be present in higher proportion in WD patients with cognitive behavioral decline. Our data suggest that the APOE ?4 allele could act as a potential risk for the pathogenesis of WD. Also, APOE and PRNP might contribute toward the cognitive behavioral decline in a section of WD patients.     

Apolipoprotein E polymorphism and stroke in a population from eastern Turkey

Human apolipoprotein E (apo E) alleles are polymorphic with significantly different frequencies among different ethnic groups and have been associated with increased risk of coronary heart disease, and postulated as a major genetic susceptibility locus for Alzheimer's disease. Studies undertaken in different populations have shown different association patterns between apo E genotype and stroke. The aim of this study was to determine the risk of apo E genotype in stroke patients living in the eastern part of Turkey. The apo E genotypes and allele frequencies of 229 individuals from the same geographic area were determined by polymerase chain reaction and restriction fragment length polymorphism, of which 103 were patients with a documented history of stroke without other apparent dementia and 126 age-matched healthy subjects as a control group. A reduced E3/4 genotype frequency was found in subjects with stroke and the E2/3 genotype frequency was elevated in patients with previous stroke. There was no association between apo E epsilon4 allele and stroke. The APOE alleles had divergent effects in this population. Association between APOE (the gene) alleles and stroke in this population may be altered due to interaction with other genetic effects. The effects of APOE alleles and genotypes require further study in different populations.     

Apolipoprotein E polymorphism is not associated with lipid levels and coronary artery disease in Greek patients with familial hypercholesterolaemia

Abstract Familial hypercholesterolaemia is a genetic disorder characterised by high low-density lipoprotein (LDL) cholesterol concentrations, which frequently gives rise to premature coronary artery disease (CAD). The clinical expression of familial hypercholesterolaemia is highly variable even in patients carrying the same LDL receptor gene mutation. This variability may be due to environmental and other genetic factors. Apolipoprotein E (Apo-E) has been extensively studied for its effects on the phenotype of familial hypercholesterolaemia. In this study we examined the influence of Apo-E genotype on lipid parameters and the incidence of CAD in 93 Greek patients with familial hypercholesterolaemia. Apo-E E2, E3 and E4 allele frequencies were 0.06, 0.86 and 0.09 respectively. The levels of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoproteins A and B and lipoprotein α did not differ significantly among carriers and non-carriers of the E4 allele. The prevalence of CAD and hypertension did not differ either. Our results suggest that the E4 allele is not associated with lipid levels or with the prevalence of CAD among familial hypercholesterolaemia patients of the Greek population. *The two authors were equally involved in the work     

Apolipoprotein A-IV polymorphism in the Hungarian population: Gene frequencies,effect on lipid levels,and sequence of two new variants

The genetic polymorphism of human apolipoprotein A-IV was investigated in Hungarian blood donors (n = 202) by isoelectric focusing (IEF) of pfasma samples followed by immunoblotting. The frequency of apo A-IV alleles was f(A-IV¹) = 0.95, f(A-IV²) = 0.039 and f(A-IV³) = 0.002. This frequency distribution is significantly different from other Caucasian populations (P < 0.05). The association of apo A-IV phenotypes with HDL-cholesterol concentration which was previously described for two other European populations was only of borderline significance (P = 0.08). Three previously undescribed apo A-IV variants, designated Budapest-1, Budapest-2 and Budapest-3, were detected by IEF. The mutant proteins are not associated with alterations in the lipid/ lipoprotein concentrations in heterozygotes. DN A-sequencing reveafed two point mutations (Arg²⁸⁵→ Cys and Thr³⁴⁷ → Ser) in exon 3 of apo A-IV-Budapest-1 and a Glu → Lys substitution at position 24 in exon 2 of apo A-IV-Budapest-2. © 1995 Wiley-Liss Inc.     

The effect of six polymorphisms in the Apolipoprotein B gene on parameters of lipid metabolism in a Danish population

Lipoproteins are vehicles for the distribution of plasma lipids and polymorphisms in the genes for apolipoproteins could influence the amount of lipid in plasma. We examined the effect of six single nucleotide polymorphisms in codons 71, 591, 2488, 2712, 3611, and 4154 of the apolipoprotein B gene on fasting levels of triglyceride, VLDL-, LDL-, HDL- and total cholesterol and on body mass index (BMI) in a cohort of 2656 Danes aged 40-70 years using a linear model correcting for the effects of gender, age, BMI, smoking, alcohol consumption and physical activity. The codon 2488 polymorphism was the most influential of the tested polymorphisms, significantly influencing triglyceride (P = 0.002), LDL-cholesterol (P < or = 0.0004), VLDL-cholesterol (P = 0.006) and total cholesterol (P = 0.0001). The codon 2712 polymorphism had an impact on triglyceride (P = 0.007) and VLDL-cholesterol (P = 0.001), while the codon 71 polymorphism influenced LDL- and total cholesterol (P = 0.04 and P = 0.02, respectively). An interaction between smoking and codon 591 (P = 0.03) and smoking and codon 3611 (P = 0.02) on BMI was observed, as well as modest interactions between codon 3611 and codons 2488 and 2712 on lipid parameters. All polymorphisms were in close linkage disequilibrium. The population was not in Hardy-Weinberg equilibrium in four of the six polymorphisms but the lack of equilibrium was restricted mainly to the 60-year olds.     

Apolipoprotein E polymorphism in non-diabetic patients with acute coronary syndrome.

Since a decade ago, apolipoprotein (apo) E polymorphism has been focussed as a risk factor for cardiovascular disease. ApoE plays a central role as a receptor ligand for the uptake of lipoproteins from the circulation. There was an agreement on apoE polymorphism being one of the major risk factors for coronary artery disease (CAD) by its effects on lipid profiles. However, the effects of apoE have not been noted in all populations and conflicting results in the risk of CAD have been noted. Recently, in situ expression of apoE on the atherosclerotic plaque has been studied. We, therefore, investigated the effects of apoE genotype on patients with acute coronary syndrome, including unstable angina and acute myocardial infarction, in non-diabetic patients. While we could not find significant risk effects of apoE on coronary artery disease and lipid profiles on simple comparison with the normal control group, we could find significantly decreased frequencies of apo epsilon 3 allele in patients with acute coronary syndrome compared with stable angina patients (77.8% vs 88.8%). We suggest that the apoE genotype could be associated with acute coronary events in CAD and further study with in situ biochemical methods will be needed on the effects of apoE polymorphism on plaque stability.     

Apolipoprotein E5 and E7 in apparently healthy Japanese males: Frequencies and relation to plasma lipid levels

Summary In order to determine the frequencies of apolipoproteins (apo) E5 and E7 and their relation to plasma lipid levels, apo E phenotypes were determined in 608 healthy Japanese male adults by two-dimensional gel electrophoresis. Apo E5 and E7 were observed in 2.8% of the subjects, in addition to the three common apo E isoforms, E2, E3, and E4. Apo E5 was divided into two subtypes based on the migration rate on SDS/PAGE, E5f is the type with faster migration and E5s slower migration. The gene frequencies were: the 3 allele, 0.841; the 4 allele, 0.095; the 2 allele, 0.049; the 7 allele, 0.009; the 5 allele encoding apo E5f (the 5f allele), 0.004; and the 5 allele encoding apo E5s (the 5s allele), 0.001. The five individuals with apo E5f and the eleven with apo E7 were heterozygotes and normocholesterolemic. Also plasma apo B and apo E levels were not increased in any subjects with apo E5f or apo E7. The data suggests that apo E5f and E7 are not rare in the Japanese population but that neither apo E5f nor E7 are associated with hypercholesterolemia in most of the heterozygotes.