Influence of polymorphisms for apolipoprotein B (ins/del, XbaI, EcoRI) and apolipoprotein E on serum lipids and apolipoproteins in a Javanese population

Dietary quality indices modify the effects of apolipoprotein B polymorphisms on biochemical and anthropometric factors in type 2 diabetes mellitus

We tried to identify the interaction between dietary quality indices and apolipoprotein B Ins/Del and EcoR1 polymorphisms on biochemical and anthropometric factors in patients with type 2 diabetes mellitus (T2DM). This cross-sectional study recruited 700 adults with T2DM in Tehran. The genotypes of Ins/Del and EcoR1 single nucleotide polymorphisms (SNP) were explored via polymerase chain reaction (PCR). Dietary quality index-international (DQI-I), healthy eating index-2015 (HEI-2015) and dietary phytochemical index (DPI) were calculated by semi-quantitative food frequency questionnaire (FFQ). In both crude and adjusted model for confounding factors, we observed significant interactions between DQI-I and Ins/Del SNP on leptin in and 8-iso-prostaglandin F2 α (8-iso-PGF2α), DPI and EcoR1 SNP on total cholesterol (TC) and between Ins/Del SNP and HEI-2015 on interleukin-18 (IL-18). Furthermore, in crude model there were close to meaningful interactions between EcoR1 SNP and DQI-I on total antioxidant capacity (TAC) and between EcoR1 SNP and HEI-2015 on serum leptin and superoxide dismutase (SOD) levels. Our finding indicated that the association between DQI-I, HEI-2015 and DPI with IL-18, TC, leptin and 8-iso-PGF2α in patients with T2DM might be dependent on Ins/Del and EcoR1 variants in ApoB gene.

Analysis of apolipoprotein E genetic polymorphism in a large ethnic Hakka population in southern China

There is currently no data about the genetic variations of APOE in Hakka population in China. The aim of this study was to analyze the allelic and genotypic frequencies of APOE gene polymorphisms in a large ethnic Hakka population in southern China. The APOE genes of 6,907 subjects were genotyped by the gene chip platform. The allele and genotype frequencies were analyzed. Results showed that the ∊3 allele had the greatest frequency (0.804) followed by ∊2 (0.102), and ∊4 (0.094), while genotype ∊3/∊3 accounted for 65.43% followed by ∊2/∊3 (15.85%), ∊3/∊4 (14.13%), ∊2/∊4 (3.01%), ∊4/∊4 (0.84%), and ∊2/∊2 (0.74%) in all subjects. The frequencies of the ∊4 allele in Chinese populations were lower than Mongolian and Javanese, while the frequencies of the ∊2 allele were higher and ∊4 allele lower than Japanese, Koreans, and Iranian compared with the geographically neighboring countries. The frequencies of ∊2 and ∊4 alleles in Hakka population were similar to the Vietnamese, Chinese-Shanghai, Chinese-Kunming Han and Chinese-Northeast, and French. The frequency of ∊2 in Hakka population was higher than Chinese-Dehong Dai and Chinese-Jinangsu Han. The low frequency of the APOE ∊4 allele may suggest a low genetic risk of Hakka population for cardiovascular disease, Alzheimer's disease, and other diseases.

Associations of the APOB rs693 and rs17240441 polymorphisms with plasma APOB and lipid levels: a meta-analysis

BACKGROUND

The associations of the apolipoprotein B gene (APOB) rs693 and rs17240441 polymorphisms with plasma levels of APOB and lipids have been widely explored, but the results were inconclusive. This meta-analysis aimed to clarify the associations of the rs693 and rs17240441 polymorphisms with fasting APOB and lipid levels.

METHODS

Sixty-one studies (50,018 subjects) and 23 studies (8425 subjects) were respectively identified for the rs693 and rs17240441 polymorphisms by searching in PubMed, Google Scholar, Web of Science, Cochrane Library, Wanfang, VIP and CNKI databases. The following information was collected for each study: first author, age, gender, ethnicity, health condition, sample size, genotyping, lipid assay method, mean and standard deviation or standard error of APOB and lipid variables by genotypes. A dominant model was used for this meta-analysis.

RESULTS

The carriers of the rs693 variant allele (T) had higher levels of APOB [standardized mean difference (SMD) = 0.26, 95% confidence interval (CI) = 0.16-0.36, P < 0.01], triglycerides (TG) (SMD = 0.12, 95% CI = 0.05-0.20, P < 0.01), total cholesterol (TC) (SMD = 0.24, 95% CI = 0.17-0.30, P < 0.01) and low-density lipoprotein cholesterol (LDL-C) (SMD = 0.22, 95% CI = 0.14-0.30, P < 0.01), and lower levels of high-density lipoprotein cholesterol (HDL-C) (SMD = -0.06, 95% CI = -0.11-0.01, P = 0.01) than the non-carriers. The carriers of the rs17240441 deletion allele had higher levels of APOB (SMD = 0.13, 95% CI = 0.06-0.20, P < 0.01), TC (SMD = 0.17, 95% CI = 0.07-0.26, P < 0.01) and LDL-C (SMD = 0.15, 95% CI = 0.07-0.23, P < 0.01) than the non-carriers.

CONCLUSIONS

The rs693 polymorphism is significantly associated with higher levels of APOB, TG, TC and LDL-C, and lower levels of HDL-C. The rs17240441 polymorphism is significantly associated with higher levels of APOB, TC and LDL-C. Further studies are needed to elucidate the underlying mechanisms.

Genetic Variation of ApoE Gene in Ethnic Kashmiri Population and Its Association with Outcome After Traumatic Brain Injury

The outcome from traumatic brain injury (TBI) is variable and only partly explained by known prognostic factors. Genetic factors may influence the brain's susceptibility to injury or capacity for repair and regeneration. ApoE has been implicated in modifying neurological outcome after TBI, although the mechanisms by which this occurs remain poorly defined. Apolipoprotein E is an apparently multifunctional protein involved in the response of the brain to injury and in subsequent repair processes. Several studies have shown that patients with APOE e4 have a poorer outcome after TBI. This study was aimed to analyse the genotypes of ApoE in Kashmiri population and to examine the association of APOE genotype with outcome after TBI. A total of 450 subjects (300 healthy controls and 150 TBI patients) were recruited for the study. Genotyping was done by PCR-restriction fragment length polymorphism (RFLP).Our study indicated Apoe3/e3 to be the most common genotype in this study group. The allele frequency of the Apo E gene in these study subjects was observed to be 0.07 for the e2 allele, 0.82 for the e3 allele and 0.11 for the e4 allele. However, no association between the presence of APOe4 allele and outcome after head injury was observed in this study [p = 0.92]. Thus, genotype containing the e4 allele (e4/e3 and e4/e4) was not associated with unfavourable outcome after TBI in Kashmiri population.

Correlation between the Xba I polymorphism of apoB gene and serum lipid profiles in Li ethnic group

OBJECTIVE

To study correlation between the Xba I polymorphism of apoB gene and plasma lipid profiles in Li ethnic group.

METHODS

Total 151 cases of healthy Li people were recruited randomly by cluster sampling and 200 Han people were recruited as control; blood was drawn to analyze Xba I polymorphism distribution of apoB gene and serum lipid levels.

RESULTS

There were lower serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels in serum of Li people; while, high density lipoprotein cholesterol (HDL-C), X-/X+ genotype and X+ allele frequencies exhibited higher levels than Han people. Interestingly, HDL-C level was reduced, while LDL-C level was enhanced in subjects carrying heterozygous (X-/X+) genotype compared to homozygous (X-/X-) genotype. Additionally, there were no difference in serum level of triglyceride, TC, apoprotein A (apo A) and apoprotein B (apo B) between Li and Han people, the same results were showed between X-/X+ and X-/X- genotype carriers.

CONCLUSIONS

Xba I polymorphism of apoB gene is correlated to the profiles of serum lipid level, X-/X+ genotype carriers are phenotyped with higher LDL-C level and lower level of HDL-C in Li ethnic group.

Apolipoprotein E gene polymorphism and its effect on anthropometric measures in normoglycemic subjects and type 2 diabetes

Background

Apolipoprotein E (apo E) plays a major role in lipid metabolism, obesity and accordingly in development of diabetes and coronary heart disease (CHD). Our main objective was to evaluate the association between apo E gene polymorphism with anthropometric measures.

Methods

Participants were selected from zone 17 Tehran/Iran. We assessed height, weight, body mass index (BMI), waist circumference (WC), blood pressure, serum fasting blood sugar, total cholesterol and triglycerides. Genotyping for apo E gene polymorphism was carried out using PCR-RFLP technique.

Results

Among total study population (n=311), 156 subjects were diabetic. The apo E3/E3 was the most common genotype in our population while E2 and E4 alleles had lower frequencies, respectively. After adjustment for diabetes, the apo E2 and E4 alleles were significantly associated with hypercholesterolemia and WC, respectively (p= 0.009, 0.034). This association was also related to sex and age. The probability of having abdominal obesity in E4 allele carriers was increased from 0.22 to 8.12 in women and to 3.08 in age ≥ 50 years.

Conclusions

Apo E polymorphism had significant influences on WC and total cholesterol level in patients with type 2 diabetes. This study highlights the importance of lifestyle modifications which may be more beneficial in hypercholesterolemic women carriers of E2 and E4 alleles concomitant central obesity.

ApoB-100, ApoE and CYP7A1 gene polymorphisms in Mexican patients with cholesterol gallstone disease

AIM: To determine the possible association of the ApoB-100 (XbaI), ApoE (HhaI) and CYP7A1 (BsaI) gene polymorphisms, with the development of cholesterol gallstone disease (GD) in a Mexican population.

METHODS: The polymorphisms were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism, in two groups matched by ethnicity, age and sex: patients with GD (n = 101) and stone-free control subjects (n = 101).

RESULTS: Allelic frequencies in patients and controls were: 34.16% vs 41.58% (P = 0.124) for X+ of ApoB-100; 4.46% vs 5.94% (P = 0.501) for E2, 85.64% vs 78.22% (P = 0.052) for E3, 9.90% vs 15.84% (P = 0.075) for E4 of ApoE; and 25.74% vs 27.72% (P = 0.653) for C of CYP7A1. Differences in genotypic frequencies between the studied groups were not significant (P < 0.05).

CONCLUSION: These results demonstrated that no association exists between the studied polymorphisms and cholelithiasis in this high prevalent population.

APOE distribution in world populations with new data from India and the UK

BACKGROUND

The APOE gene and its protein product is associated with a number of plasma proteins like very-low density lipoprotein (VLDL), high density lipoprotein (HDL) chylomicrons, chylomicron remnants, and plays a crucial role in lipid metabolism. The APOE gene is polymorphic and common alleles (*E2, *E3 and *E4) have been associated with a number of common and complex diseases in different populations. Due to their crucial role in metabolism and clinical significance, it is imperative that allelic variation in different populations is analysed to evaluate the usage of APOE in an evolutionary and clinical context.

AIM

We report allelic variation at the APOE locus in three European and four Indian populations and evaluate global patterns of genetic variation at this locus. The large, intricate and unexpected heterogeneity of this locus in its global perspective may have insightful consequences, which we have explored in this paper.

SUBJECT AND METHODS

Apolipoprotein E genotypes were determined in four population groups (Punjabi Sikhs, Punjabi Hindus, Maria Gonds and Koch, total individuals = 497) of India and three regionally sub-divided British populations (Nottinghamshire, East Midlands and West Midlands, total individuals = 621). The extent and distribution of APOE allele frequencies were compared with 292 populations of the world using a variety of multivariate methods.

RESULTS

Three alleles, APOE*E2, APOE*E3 and APOE*E4, were observed with contrasting variation, although *E4 was absent in the tribal population of Koch. Higher heterozygosities (>43%) in British populations reflected their greater genetic diversity at this locus. The overall pattern of allelic diversity among these populations is comparable to many European and Indian populations. At a global level, higher frequencies of the *E2 allele were observed in Africa and Oceania (0.099 +/- 0.083 and 0.111 +/- 0.052, respectively). Similarly, *E4 allele averages were higher in Oceania (0.221 +/- 0.149) and Africa (0.209 +/- 0.090), while Indian and Asian populations showed the highest frequencies of *E3 allele. The coefficient of gene differentiation was found to be highest in South America (9.6%), although the highest genetic diversity was observed in Oceania (48.7%) and Africa (46.3%). APOE*E2 revealed a statistically significant decreasing cline towards the north in Asia (r = -0.407, d.f. = 70, p < 0.05), which is not compatible with the coronary heart disease statistics in this continent. APOE*E4 showed a significant increasing cline in North European populations. Spatial autocorrelation analysis shows that the variation at this locus is influenced by 'isolation by distance' with a strong positive correlation for lower distances up to 1313 km.

CONCLUSION

Overall APOE allelic variation in UK and Indian populations is comparable to previous studies but in tribal populations *E4 allele frequency was very low or absent. At a global level allelic variation shows that geography, isolation by distance, genetic drift and possibly pre-historical selection are responsible for shaping the spectrum of genetic variation at the APOE gene. Overall, APOE is a good anthropogenetic and clinical diagnostic marker.

APOE/C1/C4/C2 hepatic control region polymorphism influences plasma apoE and LDL cholesterol levels

We characterized 102 kb of chromosome 19 containing the apolipoprotein (APO) E/C1/C4/C2 cluster and two flanking genes for common DNA variants associated with plasma low-density lipoprotein cholesterol (LDL-C) level. DNA variants were identified by comparing sequences of 48 haploid hybrid cell lines. We genotyped participants (1943 Whites and 2046 African-Americans) of the Coronary Artery Risk Development in Young Adults study for 115 variants. After controlling for the effects of the APOE epsilon2/3/4 polymorphism, a single nucleotide polymorphism, rs35136575, in the downstream hepatic control region 2 (HCR-2) was associated with LDL-C in Caucasians (P = 0.0004), accounting for 1% of variation. We genotyped rs35136575 in the Atherosclerosis Risk in Communities (ARIC) cohort (3679 African-Americans and 10 427 Whites) and in the Genetic Epidemiology Network of Arteriopathy (GENOA) sibships (1381 African-Americans in 592 sibships, 1116 Caucasians in 503 sibships and 1378 Mexican-Americans in 416 sibships), finding association with LDL-C level in ARIC Caucasians (P = 0.0064). Lower plasma LDL-C was observed with the rare allele. Plasma apoE level was strongly associated with HCR-2 variant genotype in all three GENOA samples (P </= 0.002), indicating an effect on apoE concentration. Patterns of association for plasma apo A-I, apoB, LDL-C, high-density lipoprotein cholesterol, total cholesterol and triglyceride levels with rs35136575 in the population-based samples evaluated in this study suggest a pleiotropic effect that may be context-dependent.

Apolipoprotein E polymorphism in Vietnamese children and its relationship to plasma lipid and lipoprotein levels

We investigated the frequency of apolipoprotein E (apoE) polymorphism and the effect of apoE polymorphism on plasma lipid and lipoprotein levels under different nutritional statuses in Vietnamese children living in urban and rural areas. Three hundred and forty-eight girls (aged 7 to 9 years) were randomly selected from urban and rural areas in southern Vietnam. Their apoE genotypes were analyzed by an Invader assay, and the plasma lipid and lipoprotein levels were determined by enzymatic methods using fasting blood samples. Dietary intake and anthropometry of children were also measured. The frequency of the allele epsilon 2 and epsilon 4 of the Vietnamese girls was 0.09 and 0.12, respectively. The levels of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) of the allele epsilon 2 carriers were significantly lower than those of the allele epsilon 3 carriers (P < .0001) in both the urban and rural groups. In contrast, the allele epsilon 4 carriers tended to show a higher LDL-C level than the allele epsilon 3 carriers, especially in subjects with a higher fat intake in urban area. The allele epsilon 2 carriers had the same high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) level as the allele epsilon 3 carriers, but the allele epsilon 4 carriers with a higher fat intake living in urban areas had lower HDL-C and higher TG level than allele epsilon 3 carriers. In conclusion, our findings showed that the LDL-C lowering effect of allele epsilon 2 was independent of the nutritional status, while allele epsilon 4 tended to lower HDL-C and increase the LDL-C level in a high-fat intake population. Therefore, the plasma lipid profiles of apoE epsilon 4 carriers may be a risk factor of atherogenesis in Vietnamese, who tend to have a westernized eating habit.

Apolipoprotein B signal peptide polymorphism and plasma LDL-cholesterol response to low-calorie diet

OBJECTIVE

To assess the effect of the apolipoprotein B Ins/Del signal peptide. Polymorphism on plasma lipid levels in overweight subjects before and after a low-calorie diet.

DESIGN

Diet intervention study (25% reduction in energy intake during 2.5 months) in relation to genetic factors.

SUBJECTS

A total of 231 unrelated patients (146 women/85 men) recruited on the basis of body mass index (BMI)> or =25 kg/m(2).

MEASUREMENTS

BMI, waist to hip ratio, blood lipids and lipoproteins, at entry and after 2.5 months, determination of apo B Ins/Del genotypes.

RESULTS

On spontaneous diet, subjects carrying the Del allele had higher LDL-cholesterol (Del/Del: 3.97+/-0.62 mmol/l; Ins/Del: 3.87+/-1.01 mmol/l; Ins/Ins: 3.61+/-0.88 mmol/l) (P=0.038). When submitted to low-calorie diet, subjects with Del/Del genotypes reduced their LDL-cholesterol (-16.8%) more than subjects with Ins/Del or Ins/Ins (-4.7% and +0.9%, respectively) (P=0.001).

CONCLUSION

In overweight or obese people, the response of plasma LDL-cholesterol levels to low-calorie diet is modulated by genetic variation at the apo B locus. Overweight subjects with the Del allele of the apo B signal peptide polymorphism are predisposed to high LDL cholesterol levels but their LDL cholesterol responds well to diet. These results demonstrate the importance of the interaction between genes and nutritional environment in the determination of the lipid levels.

An investigation of human apolipoproteins B and E polymorphisms in two African populations from Ethiopia and Benin

Three polymorphisms (XbaI, EcoRI, and Ins/Del) of the apolipoprotein B (APOB) gene and the polymorphism of apolipoprotein E (APOE) were investigated in two population samples of Amhara and Oromo origin from Ethiopia, and in two population samples of Bariba and Berba origin from Benin. No heterogeneity was observed within each major group. The cumulated frequencies of the APOB X+, R+, and D alleles for the Ethiopia and the Benin groups were 0.268 and 0.133, 0.958 and 0.818, 0.206 and 0.223, respectively. Regarding APOE, the cumulated allele frequencies of Ethiopia and Benin were 0.031 and 0.103 for epsilon*2 allele, 0.811 and 0.742 for epsilon*3, and 0.143 and 0.155 for epsilon*4, respectively. APOE typing performed at the protein level only in the Ethiopians revealed a variant allele, epsilon*5, found at the polymorphic level both in the Amhara and in the Oromo (cumulated frequency: 0.015). A tentative explanation for the higher frequencies of epsilon*4 and epsilon*5 alleles was sought in relation to the lifestyle and ethnicity of the two populations. Am. J. Hum. Biol. 11:297-304, 1999. Copyright 1999 Wiley-Liss, Inc.

Association of the apolipoprotein B gene polymorphisms with cholesterol levels and response to fluvastatin in Brazilian individuals with high risk for coronary heart disease

The influence of genetic polymorphism of the apolipoprotein B on lipid metabolism and coronary heart disease (CHD) risk has been demonstrated in different populations, but few studies have shown the contribution of this risk factor in individuals from Brazil. The Ins/del, Xbal and EcoRI polymorphisms of apo B were evaluated in 93 controls and in 104 Caucasian individuals presenting with a high risk lipid profile (HR1) for CHD; 54 of these subjects (HR2) were treated with fluvastatin during 16 weeks. DNA polymorphisms of the apo B gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The X(-)X(-) genotype for Xbal polymorphism was associated with higher serum concentrations of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) (p<0.01) in women of the HR1 group. The Ins/del and EcoRI polymorphisms were not associated with variation of lipid profile. After treatment with fluvastatin, TC and LDL-C levels of HR2 individuals were reduced by 23% and 30%, respectively. Individuals with II genotype had significantly greater reduction (34%) of LDL-C than those with ID/DD genotypes (27%). These results indicate that the Xbal polymorphism is associated with variation of serum TC and LDL-C levels in Brazilian women with lipid profile of risk for CHD and the Ins/del polymorphism is associated with the therapeutic response to fluvastatin.

Variation of apolipoprotein B as a possible cause of decreased low density lipoprotein clearance and hypercholesterolemia

The fractional catabolic rate (FCR) for low density lipoprotein (LDL) apolipoprotein B (apo B) was studied to explore the variations in apo B as a possible cause of hypercholesterolemia. The FCR of radioiodine labelled autologous LDL and homologous LDL isolated from a normocholesterolemic subject were compared in forty-nine type II hypercholesterolemic males and females with the mean plasma concentration of total cholesterol of 7.78 mmol/l, LDL-cholesterol 5.41 mmol/l and triglycerides 2.09 mmol/l. In most patients the autologous LDL was catabolized at an equal rate and sometimes even faster than the homologous LDL. However, twelve out of forty-nine patients catabolized homologous LDL 0.8-19.3% faster than autologous LDL and several apo B polymorphisms were determined. No apo B-3500 or apo B-3531 mutations were detected. Patients with XbaI -/- (absence of cutting site) had lower total, IDL and LDL cholesterol and LDL apoB than the other genotypes. Patients with EcoRI +/+ (presence of cutting site) had higher total, VLDL and LDL cholesterol and slower FCR for autologous LDL, and their VLDL was richer in cholesterol than that of patients with the EcoRI +/-. The MspI and ins/del polymorphisms were not associated with variations in the measured parameters. The apo E 4 was associated with higher VLDL and IDL cholesterol, higher triglycerides and LDL apo B than E 3/3. Overall, the determined apo B polymorphisms were not related to the slow clearance of autologous LDL among the 12 patients, in whom autologous LDL was cleared at a slower rate than homologous LDL. In conclusion, hypercholesterolemia can be due to particle-related slow clearance of LDL in some patients. However, this is not a common cause of hypercholesterolemia.

Effect of apolipoprotein E gene Hha I restricting fragment length polymorphism on serum lipids in cholecystolithiasis

AIM: To investigate the role of apolipoprotein E (apoE) polymorphism in the lithogenesis of gallstone and the hereditary pathogenesis of the disease.

METHODS: Polymerase chain reaction (PCR) was used to study apoE phenotypes and allele frequencies in patients with gallstones and control, and the fasting serum lipids of subjects were also measured by enzymatic methods.

RESULTS: The levels of triglyceride (TG) and very low density lipoprotein cholesterol (VLDL-C) were much higher in E_2/3 patients than that in E_2/3 control. E_3/3 patients were accompanied with remarkably low levels of high density lipoprotein cholesterol(HDL-C) and its subforms. But in E_3/4 patients there were only slight changes in levels of VLDL-C and low density lipoprotein cholesterol (LDL-C).

CONCLUSION: Different apoE phenotype patients with gallstones have different cheracteristics of dyslipidemia and the average level of serum lipids in patients with gallstones are higher than subjects without gallstones in the same apoE gene phenotype. ε2 allele is possibly one of the dangerous factors in the lithogenesis of chole-cystolithiasis.

Apolipoprotein E affects serial changes in total and low-density lipoprotein cholesterol in adolescent girls: Project HeartBeat!

Apolipoprotein E (apo E) polymorphism is a genetic determinant of lipid and lipoprotein levels and the risk for coronary heart disease. The extent to which serial patterns of change in total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations varied by apo E genotype was therefore investigated in 247 Caucasian girls aged 8 to 14 at baseline who were participating in Project HeartBeat!, a mixed longitudinal study of cardiovascular disease (CVD) risk factor development in children. Plasma lipid concentrations were determined for each participant three times per year (every 4 months) for up to 4 years from October 1991 through August 1995. Mean total cholesterol values for individuals with epsilon2/3, epsilon3/3, and epsilon3/4 genotypes were 141.7, 161.6, and 165.9 mg/dL, respectively (P < .001). Corresponding LDL-C values for individuals with epsilon2/3, epsilon3/3, and epsilon3/4 genotypes were 74.6, 94.8, and 98.7 mg/dL, respectively (P < .001). The results of longitudinal modeling indicated that age trajectories for total cholesterol and LDL-C varied significantly by apo E genotype. Individuals with epsilon3/3 and epsilon3/4 genotypes exhibited similar patterns of change in total cholesterol and LDL-C from ages 8 to 18, while individuals with the epsilon2/3 genotype demonstrated a significantly different pattern of change (age2 x genotype interaction, P < .05). For example, individuals with the epsilon2/3 genotype showed a slight increase in total cholesterol from approximately 141 to 146 mg/dL from ages 8 to 10; total cholesterol then decreased monotonically from ages 10 to 18 from 146 to 115 mg/dL. The apo E effect on total cholesterol and LDL-C and their change during adolescence is strong and may be modified by factors affecting growth, maturation, and reproductive function.

Apolipoprotein E polymorphism in indigenous Australians: allelic frequencies and relationship with dyslipidaemia

OBJECTIVES

To determine the apolipoprotein E (apoE) allelic frequencies and the effect of apoE genotype on lipid concentrations in indigenous Australian subjects.

DESIGN

Cross-sectional study.

SUBJECTS AND SETTING

155 indigenous Australians (92 women and 63 men) of mean (+/- standard deviation) age 45 +/- 17 years (SD +/- 50) were recruited without regard to history of atherosclerotic disease, in collaboration with community-based health centres in five indigenous communities in south-east Queensland. For comparison, 113 subjects of European descent and similar age distribution from the Brisbane and Gold Coast regions were also studied.

MAIN OUTCOME MEASURES

ApoE allelic frequency; apoE genotype; sex; age; diabetes status; body mass index; history of atherosclerotic vascular disease; and concentrations of total cholesterol, triglyceride, HDL-cholesterol and LDL-cholesterol.

RESULTS

The frequency of the apoE4 allele was found to be significantly higher in the indigenous subjects than in the subjects of European descent (P < 0.001). Among indigenous subjects, those with the apoE4 allele tended to have higher triglyceride concentrations and had significantly lower HDL-cholesterol concentrations than those with the apoE3/3 and 3/2 genotypes.

CONCLUSIONS

ApoE allelic frequency is likely to be one of the cluster of factors contributing to the high cardiovascular mortality of indigenous Australians.

Genetic variation in the amino-terminal part of apolipoprotein B: studies in hyperlipidemic patients

Hypertriglyceridemia is a heterogeneous lipid disorder often running in families. Variation in the apolipoprotein B (apo B) gene has been associated with serum triglyceride levels. Recently, a role of the amino-terminal end of apo B in binding with lipoprotein lipase (LPL) has been suggested. We screened the 5' end of the apo B gene in 76 Finnish severely hypertriglyceridemic (> 6 mmol/l) patients, using a single-strand conformation polymorphism (SSCP) screening method. We detected a previously unreported polymorphic C2316-->A change, causing a Val703-->Ile substitution. The minor 703 Ile allele frequency was 0.04 in hypercholesterolemic and normolipidemic population samples. This allele was associated with lower serum triglyceride levels in a normolipidemic population sample. Analysis of two previously reported polymorphisms also located in the amino-terminal domain of apo B (Thr71-->Ile and Val591-->Ala) revealed elevating effects on serum apo B concentrations in hypertriglyceridemic individuals. The 591 Ala allele was associated with elevated apo B (P=0.011), and individuals with both minor alleles (apo B 591 Ala + and apo B 71 Ile +) had higher apo B levels compared to subjects homozygous for both common alleles (P=0.004). Although no DNA sequence change seemed to be the cause of hypertriglyceridemia in our patients, genetic variation in the 5' end of the apo B gene may contribute to changes in serum apo B levels in hypertriglyceridemic patients.

Study of apoB gene signal peptide insertion/deletion polymorphism in a healthy Serbian population: no association with serum lipid levels

The apolipoprotein B (apoB) signal peptide polymorphism was studied in unrelated healthy individuals. A total of 232 women and 222 men were analyzed separately. The relative frequencies of Del allele in women and men were 0.42 and 0.37, respectively. More heterozygous individuals were detected in comparison with other populations, using a modified silver staining method on polyacrylamide gel for visualization of Ins and Del alleles. There was no statistically significant difference in mean lipid levels adjusted for age, BMI, smoking habit and blood pressure between the three Ins/Del genotypes in both samples (ANOVA). Therefore, no differences were shown in the genotype frequency distribution throughout the lipid quartiles.

Polymorphism of the apolipoprotein E gene and early carotid atherosclerosis defined by ultrasonography in asymptomatic adults

Clinical and autoptical studies have suggested a predisposing role of the allele E4 of apolipoprotein E (apoE) in the development of atherosclerosis and cardiovascular disease. To investigate the possible contribution of apoE allele polymorphism to the carotid intima-media thickness (IMT) as assessed by ultrasound, we studied 260 asymptomatic nondiabetic subjects (121 men, 139 women; mean +/- SD age, 53 +/- 7 years), randomly selected from the population register of the inhabitants of Trieste, Italy. B-mode ultrasound was used to quantify the maximum IMT at 12 sites on the near and far wall of the common, bifurcation, and internal carotid arteries. ApoE genotypes were determined from amplified apoE sequences by restriction isotyping. The frequencies of E2, E3, and E4 alleles were 0.073, 0.827, and 0.100, respectively. As expected, subjects with E4 allele had the highest levels of total serum cholesterol and LDL cholesterol, subjects with E2 allele had the lowest levels, and those with E3 genotype had intermediate levels. The echographic measurements of carotid IMT showed increasing values from E2 to E4 carriers. After adjustment for total and LDL cholesterol serum levels, triglycerides, ratio of LDL to HDL cholesterol, age, sex, and body mass index, ANCOVA showed that the common carotid IMT was significantly greater (P = .029) in subjects with E4 allele compared with E3 carriers. Our data confirm the influence of apoE4 on cholesterol levels and clearly show that apoE genotype affects carotid atherosclerosis in its early stages in middle-aged asymptomatic subjects.

The National Institute on Aging/Alzheimer's Association recommendations on the application of apolipoprotein E genotyping to Alzheimer's disease

In a conference held in Chicago during October 1995, a working group of the National Institute of Aging (NIA) and the Alzheimer's Association (AlzA) drafted consensus recommendations on research and clinical applications of APOE genetic susceptibility testing for Alzheimer's disease (AD). The NIA/AlzA Working Group concluded that in considering future applications of APOE genotyping and other knowledge that has been gained about the genetic basis of AD, the interests of AD patients and their family members must be held paramount. The group acknowledged that a robust association exists between possession of the APOE epsilon 4 allele and the risk of late-onset AD and cited evidence that this allele is more strongly associated with AD than any other form of dementia. They recommended against the use of APOE genotyping to predict the-future development of AD in asymptomatic individuals at this time, and warned against the use of the test in isolation as the sole means for diagnosing AD. The group endorsed the concept of discretionary use of APOE genotyping as an adjunct to other AD diagnostic procedures. However, routine clinical use of the test for this purpose was not recommended at this time. Physicians were advised to weigh any potential benefits of testing against the possibility that genotype disclosure could adversely affect the insurability, employability, and social standing of AD patients and their family members. Adequate provisions for pre-test and post-test counseling and psychosocial support were advised for all future clinical and research applications of APOE genotyping. The group called for the development of improved protocols for AD genetic counseling as well as supplemental measures to assure genetic privacy for AD patients and their family members.

Effects of apo B and apo E gene polymorphisms on lipid and apolipoprotein concentrations after a test meal

The role of apo B signal peptide and apo E polymorphisms, and individual factors (age, sex, etc.) have been investigated on the interindividual variability of the postprandial response of 274 subjects ingesting a 1.260-KJ milkshake. The mean postprandial response, observed during 4 h, is significantly positive for total cholesterol (P < 0.005), LDL-cholesterol (P < 0.0001), triglycerides (P < 0.001), apo E (P < 0.0001) and glucose (P < 0.0001), whereas HDL-cholesterol, apo A-I and apo B do not present mean postprandial variation. Independently of the mean response, some parameters present a large interindividual variability of response, which is significantly influenced by cofactors, such as weight or BMI, for total and LDL-cholesterol, apo B and apo E or tobacco use for HDL-cholesterol. Sex has no effect on any lipid levels. Total, LDL-cholesterol and apo E responses are correlated with their corresponding fasting values. ApoB signal peptide polymorphism is not involved in the postprandial responses, whereas apo E polymorphism explains a significant part of the variability of HDL-cholesterol and apo A-I responses.

Polymorphisms of the apolipoprotein E gene and severity of coronary artery disease defined by angiography

In a recent study, we could account for only about 50% of the variance in angiographically determined severity of coronary artery disease (CAD) with use of lipid and clinical variables as predictors. To explore the possible contribution of the apolipoprotein (apo) E polymorphisms to the severity of CAD (rather than to its occurrence), we studied 424 white patients aged 65 years or less consecutively referred for coronary angiography. Among the 304 male and 120 female patients, there were 110 with no significant CAD and 118 with one, 96 with two, and 100 with three significantly diseased major coronary arteries (> 50% luminal obstruction). The allele frequencies were 0.068 for E2, 0.759 for E3, and 0.172 for E4. The E2 frequency was slightly lower and E4 higher than the frequencies reported for healthy white populations (E2: 0.072 to 0.130; E4: 0.136 to 0.160). There was a clear association between the apo E genotype and the number of significantly diseased vessels (regression coefficient = .12, P = .008). The frequency of the E4 allele increased linearly with the increase in CAD severity in both sexes (for none, one, two, and three significantly diseased vessels; female patients: 0.136, 0.161, 0.200, and 0.324; male patients: 0.136, 0.167, 0.132, and 0.229, respectively, P < .01). The frequencies of the E2 allele, on the other hand, decreased with increasing severity (for none, one, two, and three significantly diseased vessels; female patients: 0.091, 0.018, 0.050, and 0.029; male patients: 0.073, 0.089, 0.072, and 0.054, respectively, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)