DNA polymorphisms of the apolipoprotein B gene in Chinese coronary artery disease patients

Apolipoproteins—New Biomarkers of Overweight and Obesity among Childhood Acute Lymphoblastic Leukemia Survivors?

Patients suffering from childhood acute lymphoblastic leukemia (ALL) are at risk of late adverse treatment-related effects. The examination of targeted biomarkers could be used to improve the diagnosis and prediction of life-threatening ALL sequelae. The purpose of this cross-sectional study was to search for treatment-related alterations in apolipoprotein (Apo) levels as potential markers of the occurrence of obesity in subjects treated for ALL, and to assess the relationships between weight, gender, anticancer treatment, and Apo concentrations. Fifty-eight ALL survivors were included in the study. The mean time of follow-up after treatment cessation was 5.41 ± 4.29 years. Serum levels of apolipoproteins were measured using a multiplex assay kit. Among ALL survivors, we observed a significant correlation of Apo-C1, Apo-C3, Apo-H, and Apo-J levels, depending on body mass index (BMI). Marked differences were observed in the area under the curve of Apo-A1, Apo-A2, Apo-C1, Apo-D. In our study, patients with a history of childhood ALL developed alterations in their Apo profile. Furthermore, this is the first study revealing that some apolipoproteins may act as valuable biomarkers useful in the prognosis of metabolic imbalance. We believe that this paper, at least partially, will highlight the importance of long-term prognosis of metabolic complications associated with the anticancer chemotherapy used to treat hematological malignancies in children.

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.

Association between apolipoprotein B EcoRI polymorphisms and coronary heart disease : A meta-analysis

OBJECTIVE

The study was carried out to examine the association between apolipoprotein B (ApoB) EcoRI polymorphism (E^- vs. E⁺) (rs1042031) and coronary heart disease (CHD) risk by systematically analyzing multiple independent studies.

METHODS

The Hardy-Weinberg equilibrium (HWE) test was applied to assess genotype frequency distribution in healthy controls. The quality of the studies was assessed using the Newcastle-Ottawa scale (NOS). Power analysis was performed with Power and Precision V4 software. A fixed effect model was used because no deviation from homogeneity was found. Publication bias was quantified and examined with Begg's funnel plot test and Egger's linear regression method. The meta-analysis was performed by Stata 12.0 software.

RESULTS

A total of 21 eligible association studies were merged in this meta-analysis and the pooled sample consisted of 2994 CHD patients and 3258 healthy controls. No significant publication bias and heterogeneity were observed in these studies. The pooled odds ratio (OR) and 95% confidence interval (CI) of E^- vs. E⁺ were 1.18 (1.06-1.32). The pooled OR (95% CI) of E⁺ E^- + E^- E^- vs. E⁺ E⁺ was 1.18 (1.04-1.34).

CONCLUSIONS

This meta-analysis indicated that ApoB EcoRI confers a moderate risk for CHD and the E^- allele at this locus might be a susceptibility allele for the development of CHD.

Association between apolipoprotein B gene polymorphisms and the risk of coronary heart disease (CHD): an update meta-analysis

OBJECTIVE

Polymorphisms in the apolipoprotein B (apoB) gene have been reported to be associated with coronary heart disease (CHD). However, the results on this topic are conflicting. The present study aims to derive a more precise estimation of the relationship between CHD and apoB genetic polymorphisms by meta-analysis.

METHODS

We identified a total of 54 studies involving 7236, 10,912, and 14,102 individuals, respectively, for EcoRI, XbaI, and SpIns/Del polymorphisms by searching in PubMed, Web of Science, Google Scholar, the Cochrane Library, Wanfang Data, SinoMed, and CNKI. We utilized RevMan 5.0 software to perform the meta-analyses.

RESULTS

A significant statistical association between apoB EcoRI polymorphism and CHD was observed under an allelic (p = 0.001, odds ratio (OR) = 1.33, 95% confidence interval (CI) = 1.12-1.57), dominant (p = 0.005, OR = 1.22, 95% CI = 1.06-1.40), and recessive (p = 0.04, OR = 1.33, 95% CI = 1.01-1.74) model. We also found similar association of apoB SpIns/Del polymorphism with CHD. However, we did not find association between apoB XbaI polymorphism and CHD.

CONCLUSION

The current meta-analysis found an association of EcoRI polymorphism and SpIns/Del polymorphism with an increased risk of CHD. No significant association between apoB XbaI polymorphism and CHD we observed in the present study.

Association between the APOB XbaI and EcoRI polymorphisms and lipids in Chinese: a meta-analysis

Background

No previous meta-analysis was to report the association between the apolipoprotein B (APOB) XbaI and EcoRI polymorphisms and serum lipids in Chinese. We performed the study to investigate their potentially association.

Methods and Results

Studies in English and Chinese were found via a systematic search of Pubmed, Embase, CNKI and Wanfang databases. The dominant genetic model and random-effects model were used to pool data from individual studies. As a result, a total of 30 articles with 5611 subjects for XbaI and 2653 subjects for EcoRI were included in the current study. For the XbaI polymorphism, overall, subjects carrying X+ allele were significantly associated with higher TC,TG and LDL compared with X-X- genotype (Pvalue =0.0006, OR (95 %) = -0.55 (-0.86,-0.23); Pvalue = 0.0004, OR (95 %) = -0.30 (-0.47,-0.14); (Pvalue = 0.05, OR (95 %) = -0.23(-0.46,-0.00), respectively). Similar results were observed in the subgroups of Han, healthy individuals (HT), coronary heart disease (CHD), cerebral infarction (CI), and cholelithiasis. For HDL, positive association between X+ allele with Lower lipid value was found in CHD and CI subgroups. For EcoRI polymorphism, overall, the E- allele carriers were found to be obviously linked with elevated LDL and lower HDL compared with E + E+ genotype (Pvalue = 0.02,OR (95 %) = -0.27 (-0.49,-0.05); Pvalue = 0.01, OR (95 %) = 0.17 (0.03, 0.30), respectively). TC was significantly high in subjects carrying E- allele in the subgroup of hyperlipidemia. No evidence of publication bias was observed.

Conclusions

The two genetic variants of APOB may be associated with serum lipids in Chinese.

Genetic association of APOB polymorphisms with variation in serum lipid profile among the Kuwait population

BACKGROUND

Several studies have identified APOB as a candidate gene predisposing individuals to dyslipidemia. Polymorphisms including the signal peptide (rs11279109), codon 2488 XbaI (rs1042031), codon 3611 MspI (rs693), codon 4154 EcoRI (rs1801701) and the 3' variable number of tandem repeats have been reported to be associated with dyslipidemia in several populations. With limited studies on Arabs, this study aimed to investigate the genetic association of APOB polymorphisms and assess the potential influence of minor and rare alleles on serum lipid levels in the Kuwaiti population.

METHODS

A total of 795 Kuwaiti subjects, documented with phenotypic data and fasting serum lipid levels, were genotyped for the five polymorphisms using PCR, PCR-RFLP and gene fragment analysis. Genotype and allele association with variation in serum lipid levels as well as haplotypes were analyzed using chi-square test, univariate and logistic regression analysis.

RESULTS

Analysis of the genotype and allele frequencies distribution revealed a significant positive association between the APOB signal peptide and 3611 MspI polymorphisms with increased levels of triglycerides (statistical power of 80%). Haplotype analysis further supported the findings by showing that carriers of haplotypes (IX-M-E+M) had significantly lower mean (SD) TG levels (0.86 ± 0.07) as compared to non-carriers (1.01 ± 0.02). Significance was also observed with regards to positive family history of hypercholesterolemia.

CONCLUSION

The results imply a "protective role" for two alleles (rs11279109 and rs1801701) in which logistic regression analysis showed a significant half-fold decrease in the risk for heterozygotes of rs11279109 and an 8.8 fold decrease in the risk for homozygous M-M- of rs1801701 of having lower TG levels (<1.70 mmol/L) in individuals. This suggests that genetic interaction between various polymorphisms at different gene loci act in linkage disequilibrium to affect serum TG levels. Apo B genotyping may be a useful adjunct for the identification of individuals at risk of developing dyslipidemia in order to provide them with lifestyle modifications and/or pharmacological intervention to mitigate the effects of gene interaction and environmental influence.

Apolipoprotein A-II: evaluating its significance in dyslipidaemia, insulin resistance, and atherosclerosis

Reduced HDL cholesterol, commonly found in subjects with obesity and type 2 diabetes, is associated with increased risk of cardiovascular disease (CVD). ApoA-II, a constituent apolipoprotein of certain HDL particles, plays an important role in the regulation of cholesterol efflux, HDL remodelling, and cholesteryl ester uptake via its interactions with lipid transfer proteins, lipases, and cellular HDL receptors. Recent studies have linked apoA-II directly with triglyceride and glucose metabolism. Most of the data are, however, derived from cellular systems and transgenic animal models. Direct evidence from human studies is scarce. Clinical studies demonstrate that apoA-II is a strong predictor of risk for CVD. There is no evidence, however, that selective therapeutic modification of apoA-II impacts on atherosclerosis and clinical outcomes. More research is required to investigate further the significance of apoA-II in clinical medicine.

Nuclear Cardiology: Present and Future

Nuclear cardiology has made significant advances since the first reports of planar scintigraphy for the evaluation of left ventricular perfusion and function. While the current "state of the art" of gated myocardial perfusion single-photon emission computed tomographic (SPECT) imaging offers invaluable diagnostic and prognostic information for the evaluation of patients with suspected or known coronary artery disease (CAD), advances in the cellular and molecular biology of the cardiovascular system have helped to usher in a new modality in nuclear cardiology, namely, molecular imaging. In this review, we will discuss the current state of the art in nuclear cardiology, which includes SPECT and positron emission tomographic evaluation of myocardial perfusion, evaluation of left ventricular function by gated myocardial perfusion SPECT and gated blood pool SPECT, and the evaluation of myocardial viability with PET and SPECT methods. In addition, we will discuss the future of nuclear cardiology and the role that molecular imaging will play in the early detection of CAD at the level of the vulnerable plaque, the evaluation of cardiac remodeling, and monitoring of important new therapies including gene therapy and stem cell therapy.

Relationship between single nucleotide polymorphism of apolipoprotein B gene and nonalcoholic fatty liver disease

AIM: To investigate the relations of single nucleotide polymorphism (SNP) of the apolipoprotein B (ApoB) gene at MspⅠ, XbaⅠ and EcoRⅠ sites with the path-ogenesis of nonalcoholic fatty liver disease (NAFLD).

METHODS: The SNP of ApoB gene at MspⅠ, XbaⅠ and EcoRⅠsites was analyzed using polymerase chain reaction and oligonucleotide arrays in 299 patients with NAFLD and 278 healthy controls. Total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), ApoB and ApoAⅠwere also detected in the blood samples from those patients and controls.

RESULTS: The frequencies of the rare allele M^- at MspⅠsite and X⁺ at XbaⅠsites were significantly higher in NAFLD patients than those in the controls (M^-: 0.065 vs 0.038, P <0.05; X⁺: 0.062 vs 0.031, P <0.05). The rare allele at EcoRⅠsite was not notably different between the patients and controls. In the MspⅠpolymorphism, The HDL-C and LDL-C levels of patients with M⁺M^- genotype at MspⅠsite were markedly higher than those with M⁺M⁺ genotype (1.75±0.25 vs 1.62±0.30, P <0.05; 3.00±0.62 vs 2.79±0.78, P <0.05). The levels of blood lipid and apolipoprotein were not significantly different between patients with different genotypes at XbaⅠ site.

CONCLUSION: The ApoB SNP at MspⅠ and XbaⅠ sites is involved in the pathogenesis of NAFLD, and the variation at MspⅠ site is associated with the regulation of LDL-C and HDL-C metabolism.

Apolipoprotein A-I/C-III/A-IV SstI and apolipoprotein B XbaI polymorphisms and their association with carotid artery intima-media thickness in the Finnish population. The Cardiovascular Risk in Young Finns Study

Apolipoprotein A-I/C-III/A-IV (apoA-I/C-III/A-IV) SstI and apolipoprotein B (apoB) XbaI polymorphisms have been shown to affect serum low-density lipoprotein (LDL) cholesterol concentrations in a sample of Finnish children. We studied whether these polymorphism are associated with carotid artery intima-media thickness (IMT), a marker of pre-clinical atherosclerosis, measured in the same subjects during their adulthood. A random sub-sample of 214 individuals from the "Cardiovascular Risk in Young Finns" study, for whom genotypes, cardiovascular risk factor data and carotid artery IMT measured in 2001 were available, were studied. Mean carotid IMT values increased according to the apoA-I/C-III/A-IV SstI genotype groups in the order of S1S1 (0.58+/-0.08 mm), S1S2 (0.61+/-0.08 mm), and S2S2 (0.70+/-0.16 mm, p=0.02, ANOVA). In multiple linear regression analysis after adjusting for age, sex and body mass index the mean IMT thickness among the S2 allele carriers was higher (p=0.02) compared to non-carriers. In logistic regression analysis the frequency of S2 allele carriers was higher among the high IMT group compared to the low IMT group (OR=4.02, CI: 1.68-9.61, p=0.002). No significant association between apoB XbaI polymorphism and carotid IMT was found. However, serum total and LDL cholesterol and apoB concentrations were significantly different among apoB genotype groups (p<0.001 for all traits). The apoA-I/C-III/A-IV SstI polymorphism is associated with carotid IMT in young Finns.

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.

Rapid detection of 3500Q and 3531 mutations and MspI polymorphism in exon 26 at the apolipoprotein B gene

Several environmental and genetic factors are associated with high levels of cholesterol. Hypercholesterolemia is the main phenotype of Familial Defective Apolipoprotein B and Familial Hypercholesterolemia that are caused by mutations at the apolipoprotein (apo) B and LDL receptor genes, respectively. Identification of the specific genetic alteration associated with hypercholesterolemia is an important issue in clinical diagnosis of high risk for CAD. Apo B gene mutations and polymorphisms are usually screened by SSCP, DGGE, and heteroduplex, which must be confirmed by DNA sequencing or by direct detection using PCR techniques. In this study, we have optimized a PCR-RFLP procedure for identification of 3500Q and 3531 mutations and MspI polymorphism at the apo B gene. The technique can be performed in a single reaction, using the restriction endonuclease MspI for simultaneous detection of 3500Q mutation and MspI polymorphism, and NsiI for detection of 3531 mutation. The procedure was validated by analysis of control DNA samples from individuals carrying these mutations. Screening of 186 Brazilian hypercholesterolemic individuals showed that the frequency of the M-allele (7.8%) of MspI polymorphism was similar to that found in other individuals with CAD. However, neither 3500Q nor 3531 mutations were detected in this group. In conclusion, this procedure is simple and rapid, being easily introduced in clinical laboratories for direct detection of the more frequent mutations at the apo B gene associated with hypercholesterolemia.

Apolipoprotein B gene polymorphisms: prevalence and impact on serum lipid concentrations in hypercholesterolemic individuals from Brazil

Genetic polymorphisms at the apolipoprotein B (apo B) have been associated with elevated plasma concentrations of low-density lipoprotein (LDL) cholesterol, atherosclerosis and increased risk for coronary artery disease (CAD). In the present study, four apo B gene polymorphisms (MspI, XbaI, Ins/Del and 3'HVR) have been investigated to determine their frequencies and influence on the lipid profile of 177 hypercholesterolemic white Brazilian subjects (HG) and 100 control individuals (CG). The genotype distribution and allele frequency of MspI, XbaI and Ins/Del polymorphisms of apo B gene were similar between HG and CG groups. The frequency of the alleles smaller than 43 repeats (< or =43) of 3'HVR polymorphism in the HG group was higher when compared to controls (16.4 vs. 8.5%, P<0.05). Moreover, these alleles were associated with higher total cholesterol concentrations in serum of hypercholesterolemic individuals (P<0.05). In addition, an association between Ins/Del and 3'HVR polymorphism was observed. The alleles < or =43 and Del were more frequent in the HG when compared to the CG individuals (P<0.05). We concluded that 3'HVR polymorphism at the apo B gene may be an important genetic marker to evaluate atherosclerotic disease risk.

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.

Apolipoprotein B-100 gene Xba I polymorphism and cholesterol gallstone disease

The apolipoprotein (apo) B gene Xba I polymorphism is associated with alterations in serum lipids. Disturbances in serum lipids may be a risk factor for cholesterol gallstone disease. However, the relation between the Xba I polymorphism and cholesterol gallstones is unknown. This study was aimed at characterizing the polymorphism of the apo B gene Xba I in patients with gallbladder stones and the association of Xba I polymorphism with serum lipids. Xba I genotypes were measured by PCR-RFLP, and serum lipids assayed in 190 patients with gallbladder stones and 441 control subjects. The frequency of the X+/- genotype (20.63 vs. 7.94%) and X+ allele (10.79 vs. 3.97%) was significantly higher in the patient group than in the control group. Patients with the X+/- genotype had a significantly higher concentration of total cholesterol, low-density lipoprotein (LDL)-cholesterol, and apo B in serum than patients with the X-/- genotype. The X+ allele of the apo B gene is characterized by a higher cholesterol concentration and a higher LDL-cholesterol concentration in serum, and it may be a marker for increased risk of cholesterol gallstone disease.

Plasma lipids and apolipoproteins in a population of Orang Asli ('aborigines') from West Malaysia

Plasma total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDLC) and apolipoproteins Al (apo Al) and B (apo B) were measured in a sample of subjects from the Semai tribe of Orang Asli in peninsular Malaysia. They appeared to exhibit the lowest TC ever recorded (1.6 for males and 1.9 mmol/l for females) and relatively high TG (1.4 mmol/l for males and 1.5 mmol/l for females)(means for the whole sample). There was little apparent aging gradient in any of the plasma analytes. but the group of men aged 21-40 had lower HDLC than the corresponding female group. Both low density lipoprotein cholesterol (LDLC) (calculated) and HDLC as well as their corresponding apolipoproteins were correspondingly very low. There was a significant correlation between apo AI and HDLC in both sexes.

Frequencies of five genetic polymorphisms in coronarographed patients and effects on lipid levels in a supposedly healthy population

Allele frequencies of genetic polymorphisms were compared between supposedly healthy subjects and angiographically proven coronary artery disease patients. The polymorphic candidate loci investigated were the apolipoprotein (apo) B signal peptide and XbaI polymorphism, the apo E polymorphism and two polymorphism of lipoprotein lipase (LPL) gene: Hind/III and PvuII. Apo B signal peptide and HindIII/LPL polymorphisms showed significant differences in allele partition between cases and controls; the rare alleles of both polymorphisms were less frequent (p < 0.05) in cases. We looked for associations between the polymorphisms and lipid concentration variability in a supposedly healthy population (145 men and 144 women). Apo B signal peptide, apo E and PvuII/LPL polymorphisms seem to influence some lipid metabolism parameters significantly. Apo AI and LpCIII levels were significantly different among apo B signal peptide genotypes: Del homozygotes had the highest concentrations of both variables. The epsilon 4 allele of apo E polymorphism was associated with increased concentrations of total cholesterol, LDL cholesterol and apo B. Increased LpAI:AII levels observed in E3 homozygotes (p < 0.01) have not previously been reported. LpAI:AII concentration was also influenced by PvuII/LPL polymorphisms.

Polymorphism of the apolipoprotein B gene and blood lipid concentrations in Japanese and Caucasian population samples

To examine whether a racial difference in apolipoprotein B (Apo B) gene polymorphism between Japanese and American Caucasians corresponds with the lower blood cholesterol concentrations in Japanese than in Americans, we examined the EcoRI polymorphism of the Apo B gene for 271 nonsmoking men and women aged 47-69 years in two population-based samples: rural Japanese living in Akita and Caucasians living in Minneapolis-St. Paul, Minnesota, USA. Mean values of serum cholesterol concentrations were significantly lower in Japanese than in Caucasians for both men and women (difference = 25-26 mg/dl). An allele-specific polymerase chain reaction was conducted to examine the Eco RI cutting site at the 12669 cDNA position of the Apo B gene. The allele R2 (absence of the cutting site) has been associated with lower cholesterol concentrations in two previous studies. The frequency of the R2 allele was 6% for Japanese and 17% for Caucasians (P < 0.001), and this race difference in allele frequency was identical for men and women. After controlling for age, body mass index, alcohol intake, and for women, menopausal status and hormone replacement therapy, the adjusted mean (SE) cholesterol level among Japanese was 204 (3) mg/dl for genotype R1R1 and 185 (7) mg/dl for genotype R1R2 or R2R2 combined (P = 0.01). The respective mean values among Caucasians were 224(5) mg/dl and 232(7) mg/dl (P = 0.36). The polymorphism had a similar effect on total cholesterol concentrations for both men and women. The observed lower prevalence of the R2 allele in Japanese than in Caucasians indicates that this variation in the Apo B gene does not explain the racial difference in blood cholesterol concentrations.

Association of polymorphisms of the apolipoprotein B gene with coronary heart disease in Han Chinese

Four polymorphic sites of the apolipoprotein B (apo B) gene were investigated by using polymerase chain reaction (PCR) in 103 patients with coronary heart disease (CHD) and 100 age-matched healthy individuals selected from a population of Han Chinese in the Beijing area. The rare X+ allele of the XbaI restriction site was more frequently seen in CHD patients than in controls (0.088 vs. 0.025, P < 0.01). The relative frequency of rare E- allele of the EcoRI restriction site was significantly higher in CHD patients compared with controls (0.11 vs. 0.04, P < 0.01). Similarly, 3'VNTR-L allele (number of repeat units > 39) at the VNTR region was also present at an apparently high frequency in CHD patients in comparison to that in controls (0.602 vs. 0.290, P < 0.001). However, the difference in relative frequency of rare Del allele of the Ins/Del polymorphism at the signal peptide was not significant between the two groups (0.282 vs. 0.235. P > 0.05). In comparison with Caucasians, the relative frequencies of rare alleles (Del, X+ and E-) were found to be statistically lower in Han Chinese. Furthermore, the Del and X+ alleles, in linkage disequilibrium, were associated with significantly lower plasma level of HDL-C in CHD patients. Therefore it is suggested that genetic variation with the apo B gene may exert some impact on lipid metabolism and contribute to the susceptibility to development of CHD in Han Chinese.

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

A total of 231 healthy subjects from a central Javanese population were investigated for the distribution of three apolipoprotein B (apo B) polymorphisms (ins/del, XbaI, and EcoRI), as well as apolipoprotein E (apo E) polymorphism in relation to serum lipid and apolipoprotein concentrations. The frequencies of the rarer alleles (del, 0.09; X+, 0.1; and R-, 0.06) were lower than have been found for some Asian and European populations. Distribution of genotypes was in Hardy-Weinburg equilibrium for all the polymorphisms. A linkage disequilibrium was observed only between the ins/del and XbaI site polymorphisms of apo B (chi 2(4)) = 25.3; P < 0.001) consistent with that observed in some other population studies. No polymorphism of the apo B gene had an association with serum lipid or apolipoprotein concentrations in this population except for XbaI, which appeared to be associated with serum TG (as the log transform: R2 = 8.3; F = 4.8; P < 0.01). The apo E4 allele was found to be associated with significantly higher serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC). Apo E polymorphism explained 5.9% of the sample variance of serum LDLC (F = 5.4; P < 0.01).

DNA polymorphisms of the apolipoprotein B gene are associated with obesity and serum lipids in healthy Indians in Singapore

Three DNA polymorphisms (Ins/Del, XbaI and EcoRI) of the apolipoprotein B gene and their influence on body-mass index, serum lipids and apolipoprotein levels were studied in 181 healthy Indians of both sexes (121 males and 60 females), aged between 17 and 71 years. The frequencies of X+ (XbaI) and Del (Ins/Del) of the signal peptide region in Indians were found to be significantly lower (0.17 and 0.11, respectively) compared to the frequencies in Caucasians (0.50 and 0.32, respectively) (P < 0.025). The frequency of E- (EcoRI) was similar to that in Caucasians (0.10 vs 0.15). A highly significant linkage disequilibrium was observed between the XbaI site and Ins/Del polymorphism of the apo B gene in this sample (X2 = 31.9, P < 0.001). The simultaneous presence of Del and X+ allele was significantly associated with higher body mass index (X2 = 11.43, P < 0.005), serum total cholesterol (X2 = 5.11; P < 0.025) and triglyceride (X2 = 6.42; P < 0.025) levels. Mean values of adjusted BMI and serum triglyceride levels were found to be 29.0 +/- 1.92 vs 23.7 +/- 0.67 (P < 0.025) and 278.0 +/- 60.78 vs 140.4 +/- 15.43 mg/dl (P < 0.05), respectively, in subjects with Del and X+ compared to others. The multiple regression tests showed that 3.3 and 5.8% of the total variability of BMI is explained by Ins/Del and XbaI polymorphism, respectively, in this sample (P = 0.06 and 0.02), while 3.8% of serum triglyceride levels was explained by Ins/Del polymorphism of the apo B gene (P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)