Reciprocal effects of apolipoprotein E alleles (ε2 AND ε4) on plasma lipid levels in normolipidemic subjects

A significantly lower frequency of the epsilon 2 allele and a significantly higher frequency of the epsilon 3 allele were found in the normolipidemic Japanese population than those in the normolipidemic Caucasian populations. We have compared plasma lipid variables among the apolipoprotein (apo) E phenotype groups and estimated the average effects of the three common alleles (epsilon 2, epsilon 3 and epsilon 4) on plasma lipid levels in normolipidemic subjects. Plasma triglyceride (TG), very low density lipoprotein (VLDL)-TG, VLDL-cholesterol (C) and apo E levels were high in the apo E3/2 group, intermediate in the apo E3/3 group and low in the apo E4/3 group, whereas plasma total cholesterol (TC), low density lipoprotein (LDL)-C and high density lipoprotein (HDL)-C levels were low in the apo E3/2 group, intermediate in the apo E3/3 group and high in the apo E4/3 group. Furthermore, the epsilon 2 allele had an effect to increase the TG, VLDL-TG, VLDL-C and apo E levels and decrease the TC, LDL-C and HDL-C levels, whereas the epsilon 4 allele had an effect opposite to the epsilon 2 allele. These results indicate that the epsilon 2 and epsilon 4 alleles have the reciprocal effects on plasma lipid, lipoprotein and apo E levels.     

Increased frequencies of apolipoprotein ε2 and ε4 alleles in patients with ischemic heart disease

It has been demonstrated that the genetic polymorphism of apolipoprotein (apo) E is associated with atherosclerosis. Thus, in this study, we have examined the apo E allele frequencies in 109 patients with ischemic heart disease (IHD) and 576 Japanese people as controls, and we have compared these frequencies between patients with IHD and controls. The frequencies of the epsilon 2 and epsilon 4 alleles were significantly higher in patients with IHD than in the controls (epsilon 2: 8.2% vs 3.7%, epsilon 4: 17.0% vs 11.7%), whereas the frequency of the epsilon 3 allele was significantly lower in patients with IHD than in the controls (74.8% vs 84.6%). The epsilon 2-carrying patients with IHD were characterized by type III (43.8%) and IV (25.0%) hyperlipoproteinemia (HLP), whereas the epsilon 4-carrying patients with IHD were characterized by hypercholesterolemia (type IIb HLP: 42.8%, type IIa HLP: 28.6%). It is concluded that both epsilon 2 and epsilon 4 alleles are more associated with IHD than the epsilon 3 allele.     

载脂蛋白E基因多态性在云南省德宏州傣族人群的分布

目的　探讨云南省德宏州傣族人群和昆明汉族人群载脂蛋白E(apolipoprotein E,apo E)基因多态性分布情况。方法　收集171名德宏傣族和71名昆明汉族人群基因组,通过聚合酶链反应-限制性片段长度多态性方法检测apo E基因第4外显子第112位和15 8位的多态性。结果　傣族组apo Eε2 / 2、ε2 /3、ε2 / 4、ε3/ 3、ε3/ 4、ε4 / 4基因型频率依次为:0 .0 0 6、0 .111、0 .0 0 6、0 .789、0 .0 88、0 .0 0 0 ;汉族组依次为:0 .0 0 0、0 .16 9、0 .0 14、0 .718、0 .0 99、0 .0 0 0。apo Eε2、ε3、ε4等位基因频率在傣汉两民族中依次为:0 .0 6 4、0 .889、0 .0 4 7;0 .0 92码、0 .85 2、0 .0 5 6 (P>0 .0 5 )。结论　apo E基因型频率和等位基因频率均存在着民族、种族差异。与国内其它少数民族比较,德宏傣族人群apo Eε2等位基因频率显著低于壮族(P<0 .0 1) ;ε3等位基因频率显著高于朝鲜族、回族、蒙古族、壮族(P<0 .0 5 ) ,极显著高于维吾尔族(P<0 .0 1) ;ε4等位基因显著低于鄂伦春族(P<0 .0 5 ) ,极显著低于维吾尔族、鄂温克族(P<0 .0 1)。与不同种族人群比较,德宏傣族人群apo E基因多态性分布与日本人接近(P>0 .0 5 ) ,而与新加坡、欧美国家人群有较大的差异性。     

Apolipoprotein E polymorphism in northwestern Greece: frequency and effect on lipid parameters

Apolipoprotein (apo) E gene polymorphism and its effect on serum lipid parameters were examined in a Greek population originating from northwestern Greece (n = 555). The allele frequencies were epsilon2: 6.3%, epsilon3: 80.7%, and epsilon4: 13.0%. The epsilon4 allele frequency was higher in our population than was previously reported in individuals from other parts of Greece. ApoE polymorphism was associated with significant differences in serum lipid, and lipoprotein levels. Particularly, individuals with the epsilon2 allele had higher serum triglyceride and apoE levels and lower levels of total cholesterol, low-density lipoprotein cholesterol, and apoB, compared to those with the alleles epsilon3 and epsilon4. However, the impact of the epsilon4 allele on lipid parameters seen in other populations was not observed in our population. Furthermore, the combination of apoE polymorphism and serum apoE concentration explained a larger percentage of serum lipid variability than the polymorphism alone. In conclusion, the results of our study suggest that ethnic differences, as well as alterations of serum apoE levels, significantly modify the relationship between apoE gene polymorphism and serum lipid variability.     

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 alleles in women with pre-eclampsia

AIMS: To investigate the frequency of three apolipoprotein E (apoE) alleles among women with pre-eclampsia. METHODS: The presence of the three most common apoE alleles (epsilon 2, epsilon 3, epsilon 4) was determined by polymerase chain reaction-restriction fragment length polymorphism in two groups of women: healthy pregnant women (n = 91) and pregnant women with a diagnosis of pre-eclampsia (n = 133). In addition, the frequencies of the alleles in the general population in this area are presented for comparison. RESULTS: The frequency of the apo epsilon 4 allele was 18.4% among women with pre-eclampsia and 18.7% among healthy pregnant women (Fisher's exact test; p = 0.941), which is close to the rate in the general population in this area (19%). None of the apolipoprotein E genotypes was significantly over-represented, and homozygous genotype epsilon 4 was not associated with more severe clinical disease than were the other genotypes. CONCLUSION: The observed profiles of allele and genotype frequencies confirm an equilibrium state between apoE polymorphism and pre-eclampsia and suggest that apoE does not play a major role in the development of pre-eclampsia.     

Apolipoprotein E gene promoter (–219G/T) polymorphism is associated with premature coronary heart disease

The relationship of two apolipoprotein (apo) E gene polymorphisms and coronary heart disease (CHD) was investigated in 118 Finnish families with premature CHD and in 110 healthy control subjects. Affected siblings and probands with premature CHD had higher frequencies of the T allele of the -219G/T promoter polymorphism and the epsilon 4 allele (genotypes epsilon 4/3 or epsilon 4/4) of the apo epsilon 2/epsilon 3/ epsilon 4 polymorphism than those of healthy control subjects. Additionally, when the two apo E gene polymorphisms were combined, affected siblings and probands had a higher frequency of the -219T allele and the epsilon 4 allele combinations than did healthy controls. The -219T and the epsilon 4 alleles both separately and together were associated with higher levels of 2-h glucose in an oral glucose tolerance test. These results indicate that the two polymorphisms of the apo E gene have similar effects on the risk of coronary atherosclerosis in families with premature CHD. This risk was not explained by the effect of apo E gene polymorphisms on cholesterol metabolism, but their effect on cardiovascular risk factor clustering with insulin resistance may be of importance. We conclude that in addition to the epsilon 4 allele, also the -219G/T promoter polymorphism of the apo E gene is associated with early onset CHD.     

Apolipoprotein E alleles and hyperlipoproteinemia in Japan

Genetic polymorphism of apolipoprotein (apo) E has been demonstrated to be associated with hyperlipoproteinemia (HLP). There are few reports on this association in Japan. Thus, in this study, we have examined the apo E allele frequencies in normolipidemia (n = 129), non-familial hypercholesterolemic (FH) type IIa HLP (n = 40), non-FH type IIb HLP (n = 35), type III HLP (n = 17), type IV HLP (n = 59), type V HLP (n = 19) and heterozygous FH (n = 51) in Japan, and compared these frequencies between normolipidemia, and different types of HLP and FH. The frequency of the epsilon 4 allele was significantly higher in type IIa (18.7%), IIb (21.4%) and V (29.0%) HLP and FH (16.6%) than in normolipidemia (8.9%), whereas the frequency of the epsilon 2 allele was significantly higher in type III (70.6%) and IV (11.0%) HLP than in normolipidemia (3.1%). These results indicate that the epsilon 4 allele is associated with non-FH hypercholesterolemia (type IIa and IIb HLP), type V HLP and FH, whereas the epsilon 2 allele is associated not only with type III HLP but also with type IV HLP.     

Association between apolipoprotein E polymorphism and Alzheimer disease in Tehran, Iran

Epsilon 4 allele of apolipoprotein E (APOE-epsilon4) is a major risk factor for Alzheimer's disease (AD). The association of APOE allele frequencies with AD remains unknown in developing countries. We examined the frequency of APOE alleles in 105 patients with AD and 129 cognitively normal subjects of similar age and sex (control group), in Tehran, Iran. The APOE-epsilon4 allele frequency was significantly higher in the AD subjects than in the control group (21% versus 6.2%, p < 0.001). In addition, the OR for APOE-epsilon4 heterozygous and homozygous subjects were 3.2 (p = 0.001) and 12.75 (p = 0.01), respectively. The OR was not uniform across age groups. The AD subjects carrying one or two APOE-epsilon4 allele showed earlier age-at-onset (p < 0.001). These data suggest that the APOE-epsilon4 allele increase the risk for AD in Tehran population in a dose and age-dependent manner. Although the APOE-epsilon2 allele frequency was lower in the AD subjects than in the control group (0.95% versus 2.7%, p = 0.15), APOE-epsilon2 was not associated with the onset of AD in Tehran's population. The OR for epsilon2 allele in AD subjects was 0.34 (p = 0.21). The genotype frequencies for epsilon3, epsilon4, and epsilon2 alleles in control subjects were 91.2, 6.1, and 2.7%, respectively. These values were similar to that reported for Turkish, Greece, Japanese, Spanish, and Moroccan populations, but they were significantly different from the reported values for the other ethnic populations. This observation emphasizes the importance of geographical location and ethnical background of the subjects in the study of APOE genotypes and their association with AD.     

载脂蛋白E基因多态性与新疆维吾尔族自然长寿的相关性研究

目的 探讨载脂蛋白E（apolipoproteinE，apoE）基因多态性与新疆维吾尔族自然长寿的关系。方法 应用聚合酶链反应-限制性片段长度多态性方法检测百岁组42名，90岁组102名，65～70岁组70名和对照组53名的apoE基因多态性。结果 百岁组apoE的ε3／3、ε2／3和ε3／4基因型频率分别为69．0％、23．8％和2．4％，其ε3、ε2和ε4等位基因频率分别为82．1％、16．7％和1．2％，百岁组ε3／4基因型及ε4、ε3等位基因频率显著低于对照组（P〈0．01），ε2／3基因型及ε2等位基因频率则显著高于对照组（P〈0．01）。百岁与opoE基因的ε2等位基因呈正关联，与ε4等位基因呈负关联。结论在新疆维吾尔族，opoE基因多态性与个体寿命密切相关，同时也应考虑到长寿是年龄依赖的多种因素影响的结果。     

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 alleles in women with severe pre-eclampsia.

This study investigated the frequency of apolipoprotein E (apoE) alleles among women with severe pre-eclampsia. The presence of the three most common apoE alleles (epsilon 2, epsilon 3, epsilon 4) was determined by polymerase chain reaction-restriction fragment length polymorphism in three groups of white women: non-pregnant healthy (n = 101), pregnant healthy (n = 52), and pregnant with a diagnosis of severe pre-eclampsia (n = 54). The frequency of apo epsilon 2 was highest among women with severe pre-eclampsia (16.6%) followed by non-pregnant women (12.9%), and those experiencing a healthy pregnancy (10.6%). The higher frequency of the apo epsilon 2 allele detected among women with severe pre-eclampsia suggests that apoE may play a role in the development of pre-eclampsia.     

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 ε4 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.     

The use of measured genotype information in the analysis of quantitative phenotypes in man. II. The role of the apolipoprotein E polymorphism in determining levels, variability, and covariability of cholesterol, betalipoprotein, and triglycerides in a sample of unrelated individuals

Recent advances in molecular biology provide measures of genotypes at loci involved in lipid metabolism. Genotypes for apolipoprotein E (apo E) and quantitative levels of total plasma cholesterol, betalipoprotein, and triglycerides were measured in a sample of 223 unrelated individuals from Nancy, France. The frequencies of the epsilon 2, epsilon 3, and epsilon 4 alleles are 0.13, 0.74, and 0.13, respectively, in this sample. Significant differences among apo E genotypes were detected for these lipoprotein phenotypes. The average effect of the epsilon 2 allele was to reduce total plasma cholesterol and betalipoprotein levels by 0.52 mmol/L and 0.98, respectively, while the epsilon 4 allele raised these levels by 0.26 mmol/L and 0.61, respectively. Apo E genotype specific correlations suggest that this locus also has an effect on the coordinated metabolism between cholesterol and triglycerides. We infer that approximately 17% of the genetic variability in total plasma cholesterol may be attributable to this apo E polymorphism. No other single locus has been identified with such a large contribution to cardiovascular disease risk factors in the general population.     

Association of apolipoprotein ɛ4 allele with hypertriglyceridemia in obesity

Hypertriglyceridemia is the most frequent lipid abnormality associated with obesity. Genetic polymorphism of apolipoprotein E (apoE) has been demonstrated to influence lipid levels. We wanted to assess the role of apoE alleles in the hypertriglyceridemias of the obese population. The apoE phenotypes and lipid status were investigated in a population of 172 obese French subjects. The frequencies of phenotypes E4/3, E4/4 and E4/2 were 29.7%, 8.1% and 2.1%, respectively, in a subgroup with triglycerides greater than or equal to 200 mg/dl (n = 37) versus 14.2%, 2.7% and 0.9% in the normolipidemic subgroup (p less than 0.005). The odds ratio of hypertriglyceridemia was 3.15 for obese subjects with epsilon 4; 27.7% of hypertriglyceridemias could be attributed to epsilon 4 allele. It is concluded that the genetic polymorphism of apoE modulates the effects of obesity on lipids and lipoproteins and that allele epsilon 4 increases the risk of obesity-induced hypertriglyceridemia.     

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 genotypes of normal and hyperlipidemic subjects.

Apolipoprotein E (apo E) plays a role in the regulation of the lipid metabolism of humans. Apo E, 229 amino acid polypeptide, is classified into three major isoform (E2, E3, E4) according to the differences of amino acid in position 112 and 158. In the normal population apo E3 isoform is most prevalent and apo E2 or E4 is frequently associated with hyperlipoproteinemia. To find out the frequency of apo E isoform distribution in the Korean population, apo E genotyping was performed. After amplification of apoE gene by polymerase chain reaction (PCR), restriction isotyping was done by cleavage with restriction enzyme Hha I and polyacrylamide gel electrophoresis. The apo E allele frequency in 73 normal subjects was 4.8% for E2, 84.9% for E3 and 10.3% for E4. In diabetic patient with hyperlipoproteinemia, the frequency of apo E allele was 6.3% for E2, 81.0% for E3 and 12.7% for E4. There was no significant difference in apo E isoform distribution between diabetics and normal populations. But in patients with cardiovascular disease with hyperlipidemia, the apo E4 allele frequency was significantly higher than normal (20.0% vs 10.3%, p < 0.005). Apo E3 was the most common isoform in normal and diabetic subjects and apo E2 isoform was rather low frequency compared to Caucasians. This pattern is similar to the Japanese population but somewhat different from other populations. From the data of a high association of apo E4 allele and cardiovascular disease with hypercholesterolemia, apo E isoform may be one of the determinants of hyperlipoproteinemia. The PCR method may be useful in apo E genotyping.     

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.     

Novel thymidylate synthase enhancer region alleles in African populations

Thymidylate synthase (TS) regulates the production of DNA synthesis precursors and is an important target of cancer chemotherapy. A polymorphic tandem repeat sequence in the enhancer region of the TS promoter was previously described, where the triple repeat gives higher in vitro gene expression than a double repeat. We recently identified ethnic differences in allele frequencies between Caucasian and Asian populations. We now describe assessment of genotype and allele frequencies of the TS polymorphism in 640 African (African American, Ghanaian and Kenyan) and Caucasian (UK, USA) subjects. The double and triple repeat were the predominant alleles in all populations studied. The frequency of the triple repeat allele was similar between Kenyan (49%), Ghanaian (56%), African American (52%), American Caucasian (54%) and British Caucasian (54%) subjects. However, two novel alleles contained 4 and 9 copies of the tandem repeat. These novel alleles were found at a higher allele frequency in African populations (Kenyan 7%, Ghanaian 3%, African American 2%) than Caucasians (UK 1%, USA 0%). The novel alleles identified in this study decrease in frequency with Western migration, while the common alleles are relatively stable. This is a unique example suggesting the influence of multiple selection pressures within individual populations. Hum Mutat 16:528, 2000.     

Apolipoprotein E and bleomycin hydrolase. Polymorphisms: association with neurodegenerative diseases

Several studies indicate a possible association between different genes and chronic neurodegenerative diseases including Alzheimer's disease (DTA). To further investigate, we have analyzed association between the apolipoprotein E (apo E) and bleomycin hydrolase (BH) polymorphisms and three groups of elderly patients: control subjects (T) (n = 68), late-onset sporadic DTA patients (DTAst) (n = 65) and other non vascular neurodegerative diseases (MNDA) (n = 52). Apo E-epsilon4 and BH-G alleles frequencies (%) are: 8.2 (T), 31.5 (DTAst), 16.4 (MNDA) and 41.4 (T), 35.6 (DTAst). No association has been observed between carrying the G allele and DTA in epsilon4 negative subjects but, our data have confirmed the earlier reports: carrying the epsilon4 allele is a dose-dependent risk factor for the DTAst (OR: 6.0, IC 95 %: 2.6-13.7) and decrease the age of symptom onset (p < 0.005). They have also suggested that apo E genotyping may be of interest to perform differential diagnosis of neurodegenerative diseases in elderly subjects.