This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Minnich, A. Articles by Davignon, J. Search for Related Content PubMed PubMed Citation Articles by Minnich, A. Articles by Davignon, J.

(Arteriosclerosis, Thrombosis, and Vascular Biology. 1995;15:1740-1745.)
© 1995 American Heart Association, Inc.

Articles

GA Substitution at Position -75 of the Apolipoprotein A-I Gene Promoter

Evidence Against a Direct Effect on HDL Cholesterol Levels

Anne Minnich; Ghislaine DeLangavant; Jacques Lavigne; Ghislaine Roederer; Suzanne Lussier-Cacan; Jean Davignon

From the Clinical Research Institute of Montreal, Montreal, Canada.

Correspondence to Dr Anne Minnich, Clinical Research Institute of Montreal, 110 Pine Avenue, West, Montreal, PQ, Canada H2W 1R7. E-mail minnica@ircm.umontreal.ca.

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Abstract The present study sought to resolve the contradictory evidence as to whether the GA substitution at position -75 of the apoA-I gene promoter raises HDL cholesterol (HDL-C) levels by examining the effect of this polymorphism in French Canadians, a relatively genetically homogeneous population. Among 308 women, carriers of the A allele displayed 12% and 10% higher mean plasma HDL-C and apoA-I concentrations, respectively, than did noncarriers. Among 345 men, no effect of the A allele was noted. The frequency distribution of HDL-C levels in women carrying the A but not the G allele appeared bimodal, with one peak corresponding to the mean of the noncarriers and a second to higher HDL-C. Thus it appears that only a subset of A alleles confers high HDL-C levels. This hypothesis was supported by data from four kindreds within which some but not all A alleles segregated with hyperalphalipoproteinemia. The data suggest that the A substitution in the apoA-I gene promoter does not directly confer high HDL-C levels but may be in linkage disequilibrium with other sequence polymorphism(s) at this locus in a subset of alleles that raise HDL-C levels.

Key Words: hyperalphalipoproteinemia • genetic polymorphism • HDL cholesterol • apoA-I gene

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Numerous population and intervention studies have demonstrated that plasma HDL-C levels are significantly inversely related to risk for coronary artery disease. Studies of subjects lacking apoA-I, the major protein component of HDL, have shown that this apolipoprotein is crucial for the assembly of HDL.^{1 2} As such, genetic factors that determine apoA-I and HDL-C levels are of considerable interest. Approximately 50% of the variability in plasma HDL-C concentrations is of genetic origin,^{3 4} and it has been estimated that variability at the apoA-I/C-III/A-IV locus accounts for one half of this effect.⁵ However, the exact sequence polymorphisms responsible for the apparent influence of this locus on HDL levels are not known.

A number of studies have suggested that a G/A polymorphism at position -75 (relative to the transcription start site) in the promoter of the apoA-I gene is associated with variability in HDL-C levels. In a sample of 96 healthy men, Jeenah et al⁶ have observed a higher prevalence (.25) of the A allele in men with plasma apoA-I levels greater than the 90th percentile than in those with lower levels (.11); carriers of the A allele had mean plasma HDL-C concentrations 20% higher than noncarriers. In contrast, Pagani et al⁷ found no effect of the A allele in 108 men, but the A allele was significantly less prevalent in the lowest 10th percentile of HDL-C levels in 136 women. Paul-Hayase et al⁸ showed that in 162 boys and young men the A allele was associated with significantly higher (4.5%) apoA-I levels than was the G allele. Because the A substitution creates an inverted DNA sequence repeat homologous to previously characterized functional regulatory elements, it is hypothesized that the substitution itself may be functionally important, perhaps by increasing the activity of a transcriptional activator.^{6 7}

However, the issue of whether the A substitution itself is directly responsible for these associations of the A allele with higher HDL-C levels is controversial. Smith et al⁹ found the A allele to be associated with significantly lower (11%) apoA-I production rates in vivo in 54 subjects, with lower rates of transcription in vitro and no differences in HDL-C or apoA-I levels. Tuteja et al¹⁰ have found that in vitro transcriptional differences between the A and G alleles depend on the length of promoter DNA used for transfection, such that the A allele is associated with lower transcription when 330 bp is used but with no differences if 1500 bp is used. Finally, Angotti et al¹¹ have shown the A allele to be associated with higher transcription in vitro regardless of the length of the promoter used in the assay.

More recently, Barre et al¹² have failed to observe any effect of the A allele on HDL-C levels in 205 women and 204 men. These authors suggest that the A substitution itself is not responsible for the apparent effect of the A allele on previously reported HDL-C and apoA-I levels but that this effect might be due to linkage disequilibrium between the A substitution and other DNA sequences that may regulate apoA-I plasma levels. The present study attempts to resolve the apparent inconsistencies among the above studies and to address the hypothesis of Barre et al¹² by examining the frequency distribution of HDL-C levels in carriers and noncarriers of the A allele in French Canadians, a population shown to be relatively genetically homogeneous.^{13 14}

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Subjects
Subjects were obtained from a sample of French Canadians selected for health¹⁵ or from normal family members of patients attending the Clinical Research Institute of Montreal. In addition, some subjects (29 women and 68 men) had been recruited from the cardiac catheterization wards of three Montreal hospitals for another study. Coronary angiography revealed no evidence for coronary artery disease in 23 of these women and 12 of the men. All subjects were unrelated to the first degree. Exclusion criteria for this group of subjects included a history of hypertension (blood pressure >160/90 mm Hg), diabetes (plasma glucose >160 mg/dL), or severe obesity. Subjects with plasma total cholesterol and TG concentrations greater than 250 and 300 mg/dL, respectively, were also excluded. Subject age ranged from 14 to 83 years in women and 13 to 72 years in men. French Canadian descent was established by interview.

In addition to this group of subjects, four families in which hyperalphalipoproteinemia segregated were studied. Two of these involved subjects with familial hypercholesterolemia. In family 1, familial hypercholesterolemia is due to the >10-kb deletion of the LDL receptor gene¹⁶ ; in family 2, to the apoB Arg₃₅₀₀Gln substitution.^{17 18 19}

The protocol for this study was approved by the institutional ethics committee, and subjects participated after their informed consent was obtained.

Lipoprotein Analysis
Plasma was isolated from the venous blood of fasting subjects. Lipoproteins were separated by ultracentrifugation at d=1.006 g/mL to obtain VLDL and by precipitation of apoB-containing lipoproteins in the d>1.006 g/mL fraction to separate LDL from HDL.²⁰ HDL₂ and HDL₃ were measured after dextran sulfate precipitation.²¹ Plasma and lipoprotein cholesterol and TG concentrations were determined by using enzymatic methods on an automated analyzer (Abbott biochromatic analyzer, model 100, Abbott Laboratories). ApoA-I was measured by electroimmunoassay on agarose gels (SEBIA). Lipoprotein lipid determinations conformed to standard Centers for Disease Control and Prevention requirements.

DNA Analysis
DNA was extracted from white blood cells by using an Applied Biosystems 340A extractor. Oligonucleotides were synthesized by the solid-phase triester method on a Pharmacia LKB gene assembler plus DNA synthesizer. A 370-bp region of human apoA-I gene promoter region was polymerase chain reaction–amplified²² from 200 to 500 ng of human genomic DNA with primers 5'-CGGATCCCTGCCCACACACTCCCATGGAG-3'and 5'-GGAATTCTGAGCTGGGGAGCCAGAGTGAC-3' at 96°C for 1 minute and 68°C for 3 minutes with a final extension of 7 minutes at 68°C. The reaction product (5 µL) was digested with Msp I (GIBCO BRL) according to the recommendations of the manufacturer. Digestion products were electrophoresed on 1.8% NuSieve (FMC BioProducts) agarose gels. Substitution of A for G results in the loss of an Msp I site, ie, a 289-bp band indicates the A allele and bands of 176 and 113 bp indicate the G allele. The Xmn I restriction polymorphism at the apoA-I/C-III/A-IV locus was determined by polymerase chain reaction.²³ Genotyping of the apoA-I/C-III/A-IV locus was also accomplished by sizing analysis of a (C_a(T_b))_c repetitive element in the third intron of apoC-III.²⁴ Alternatively, alleles were sized by amplification with HEX-labeled primer and fluorescence detection on a model 373A automated DNA sequencer (Applied Biosystems).

Statistical Analysis
Statistical analyses were performed with STATISTICAL ANALYSIS SYSTEM software (SAS Institute, Inc). Data are reported as mean±SEM. Because no significant correlation between age and plasma HDL-C levels was noted, HDL-C levels were not adjusted for age in men. Plasma HDL-C concentrations were adjusted in women by adding the residuals of the regressions of HDL-C on TG and age to the sample mean, and in men on TG only. Multiple linear regression revealed no effect of exogenous hormones in women nor of tobacco use in men or women after adjustment for TG. Differences between means were tested with a Student's t test. Significance testing for skewness of frequency distributions was done with a one-tailed t test (df=).²⁵ Bimodality was assessed by ² testing of the log maximum-likelihood statistics generated for a single normal distribution and a mixture of two distributions with equal or unequal SDs.²⁶

	Results

Top Abstract Introduction Methods Results Discussion References

 
A sample of French Canadian men and women was examined for the presence of a GA substitution at position -75 of the apoA-I gene promoter.^{6 7} The alleles with and without the A substitution were designated as A and G alleles, respectively. In men and women the prevalence of the A allele was .16 and .15, respectively. This population sample did not deviate from Hardy-Weinberg equilibrium for the genotypes AA, AG, and GG (²=0.41 and 0.33 for women and men, respectively). In 345 men and 308 women, plasma HDL-C and apoA-I concentrations were significantly inversely correlated with plasma TG concentrations (R²=.29 and .15, respectively, P<.0001). Plasma TG-adjusted HDL-C was positively correlated with age in women (R²=.03, P<.0008) but not in men.

A⁺ women displayed 12% higher average plasma HDL-C than did A^- women (P<.001) (Table 1). In addition, the mean plasma apoA-I concentration in A⁺ women was 10% higher than that in A^- women. Plasma HDL-C and apoA-I levels in A⁺ and A^- men were indistinguishable. Thus, in female but not male French Canadians the A base substitution in the apoA-I gene promoter is associated with elevated plasma HDL-C levels.

View this table: [in this window] [in a new window]   Table 1. Plasma Triglyceride and HDL-C Levels in French Canadians According to ApoA-I Gene Promoter Genotype

To look for a gene-dosage effect, plasma HDL-C and apoA-I levels in subjects homozygous and heterozygous for the A allele were compared (Table 1). In women, no evidence for a gene-dosage effect of the A allele on HDL-C was apparent. Although plasma apoA-I levels tended to be higher (5%) in female A allele homozygotes than heterozygotes, the difference was not significant. HDL-C and apoA-I levels in men homozygous for the A allele were higher (10% and 8%, respectively) than those in heterozygotes, but this difference was not significant (Table 1).

Exogenous Influences on HDL-C
Because smoking has been reported to be an important variable in determining the effect of the A allele on HDL-C levels,²⁷ the proportion of smokers in each group was compared. Among A⁺ women, 25% of the 56 subjects for whom the information was available were smokers; among A^- women, 31% of 155 subjects smoked. Among A⁺ men, 30% of 82 were smokers; among A^- men, 23% of 198 were smokers. Thus, no differences in the proportion of smokers were observed between the A^- and A⁺ subject groups.

The proportion of women taking oral contraceptives was similar in A⁺ (7 of 49, 14%) and A^- (24 of 148, 16%) subjects for whom this information was available. In addition, none of the A⁺ and 10 of the A^- women were taking hormone replacement therapy. In the current sample, neither smoking nor hormone use contributed significantly to interindividual variability in plasma HDL-C levels.

HDL-C Distribution in A⁺ and A^- French Canadian Subjects
The distribution of adjusted HDL-C levels among A⁺ women was consistent with a mixture of two normal distributions (²=10.2, 2 df, P<.01 versus a unimodal model) with peaks (means) at 50 and 77 mg/dL. The latter value corresponds to approximately the 95th percentile of HDL-C levels in this sample of French Canadian women. In contrast, this distribution among A^- women was skewed (Fig 1), with a mean of 52 mg/dL HDL-C. For the A^- women, no evidence for bimodality of the log-transformed data was apparent (²=1.2 versus a unimodal model). The distribution in A^- but not A⁺ men was skewed, with a mean of 46 mg/dL for both (Fig 1). No evidence for bimodality was obtained in either group (²=3.0 and 2.1 for A⁺ men and log-transformed distributions in A^- men, respectively).

View larger version (27K): [in this window] [in a new window]   Figure 1. Histograms showing frequency distributions of plasma HDL-C concentrations in French Canadians according to apoA-I gene promoter genotype. Plasma HDL-C concentrations were adjusted for TG levels and for age in women only. Asterisks indicate A+ allele homozygotes. For A+ women, g1 (skewness)=.48 (NS); for A- women, g1=.52 (P<.005); for A+ men, g1=.28 (NS); and for A- men, g1=.76 (P<.001).

The apparently bimodal distribution of plasma HDL-C levels among women carrying the A allele suggests that only a subset of A alleles confers a tendency to higher HDL-C levels. In an effort to further define such an allele, we examined the effect of the Xmn I polymorphism, which has been suggested as being in linkage disequilibrium with the A substitution.^{6 8} This polymorphism is located in the 5' flanking region of the apoA-I gene 3.7 kb upstream of the transcription start site.²⁸ Discordance between genotypes at the apoA-I/C-III/A-IV locus as defined by the Msp I or Xmn I sites was observed in only 19 women and 29 men. The effect of the rare Xmn I allele on plasma HDL-C levels in heterozygous men and women was similar to that of the rare Msp I (A) allele (data not shown).

A⁺ alleles could be distinguished within four families in which hyperalphalipoproteinemia is vertically transmitted with an A⁺ allele (Fig 2). The A allele has been introduced twice in each kindred, and alleles at the apoA-I/C-III/A-IV locus are identified by the size of the polymerase chain reaction fragment (in base pairs) containing variable numbers of dinucleotide repeats from intron 3 of the apoC-III gene²⁴ (Fig 2). Within each kindred, one A allele appears to segregate with high HDL-C percentiles that correspond to the second peak in the density distribution of HDL-C levels among A⁺ individuals (Fig 1), and another does not (Table 2). The mean HDL-C percentiles associated with the former and latter classes of A allele were significantly different (88th and 50th, respectively; Table 2). Interestingly, some A alleles appear to confer high HDL-C levels even in men within these families. Thus, these families present evidence for a subset of A-containing alleles segregating with high plasma HDL-C levels.

View larger version (31K): [in this window] [in a new window]   Figure 2. Pedigrees of four French Canadian families showing segregation of HDL-C levels with apoA-I alleles. Percentiles for plasma HDL-C concentrations were taken from the present population sample of French Canadians or from a heterozygous familial hypercholesterolemia (FH) clinic population (indicated by half-filled symbols in family 1 and by asterisks in family 2). In the apoC-III microsatellite, apoA-I/C-III/A-IV alleles are indicated by the size of the polymerase chain reaction fragment containing the polymorphic dinucleotide repeats (see "Methods"). For A+ alleles that appear to segregate with high HDL-C levels (ie, levels corresponding to the second peak, or approximately the 95th percentile, of the plasma HDL-C frequency distribution in Fig 1), the number is enclosed in an oval; for those that do not, the number is enclosed in a rectangle.

View this table: [in this window] [in a new window]   Table 2. HDL-C Percentiles in Four French Canadian Kindreds

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
Based on several association studies, it is currently believed that the GA substitution at position -75 in the apoA-I gene promoter confers high plasma HDL-C and apoA-I concentrations. However, much of the data on the function of this substitution in vitro are not consistent with this hypothesis. The apparent HDL-C–raising effect of the A allele could result from linkage disequilibrium or from other artifacts inherent in association studies carried out in genetically heterogeneous populations.²⁹ On the other hand, the historic and demographic circumstances leading to relatively low genetic heterogeneity in the French Canadian population have been described,¹⁴ and molecular genetic evidence of genetic founder effects for numerous diseases in this population has been reported.^{13 30 31 32 33 34} As such, the French Canadian population presents the potential to clarify the currently controversial issue of whether the GA substitution at position -75 in the apoA-I gene promoter (A allele) is directly responsible for its observed association with high plasma HDL-C concentrations.

The prevalence of the A allele in the present group of French Canadians (.15) is similar to that reported in a large study of populations from 12 European countries³⁵ but slightly lower than that seen in populations from the United States (.20¹² and .18⁸ ). However, the present study suggests that the effect of this polymorphism on plasma HDL-C and apoA-I concentrations in French Canadian women vastly exceeds those reported in other populations, ie, 14% and 9% in the present study for HDL-C and apoA-I versus 2% to 5% in European populations³⁵ and no effect in a US study.¹² In contrast to the situation in women, no differences were observed in plasma HDL-C or apoA-I concentrations between French Canadian men with and without the A allele. The presence in women and absence in men of the effect of the A allele on HDL-C levels are in agreement with the results from the large European study.³⁵

In the present study, notable differences in the frequency distributions of HDL-C levels between carriers and noncarriers of the A allele were observed. Plasma HDL-C levels in women without the A allele displayed a skewed distribution consistent with 1 mean and 1 SD, while those in A allele carriers were distributed bimodally, with one peak corresponding to the mean of the noncarrier women and a second corresponding to the 95th percentile. These observations suggest that only a subset of A alleles confers high HDL-C levels in women.

A second line of evidence against the functional importance of the A promoter substitution is the lack of an apparent gene-dosage effect. If the A substitution increases the rate of apoA-I biosynthesis, one would expect to see a greater effect in subjects homozygous for the A allele. In previous studies, as in the present study, the low prevalence of the A allele has made this question difficult to address, and in most studies the HDL-C levels of A allele homozygotes have not been reported separately from heterozygotes. Among the unrelated subjects in the present study, eight female and seven male A allele homozygotes were found. In female homozygotes, HDL-C levels were indistinguishable from those in heterozygotes, while in male homozygotes they displayed a nonsignificant tendency to be higher compared with heterozygotes or noncarriers of the A allele. In both sexes, plasma apoA-I levels in A allele homozygotes tended to be nonsignificantly higher than those in heterozygotes. Thus, although small numbers may limit interpretation of these results, no evidence for a gene-dosage effect of the A allele could be detected in these French Canadian subjects. This result is in agreement with that of Barre et al,¹² who found no effect of the A allele on HDL-C levels in a US population sample.

The GA substitution in the apoA-I gene promoter was first identified by cloning DNA from a subject in whose family the rare allele for the apoA-I Xmn I restriction fragment length polymorphism segregated with high apoA-I levels.⁶ The A allele has also been observed to be in strong linkage disequilibrium with the Xmn I 2 allele in one other population.⁸ To explore the hypothesis that only a subset of A alleles may confer high HDL-C levels, the Xmn I restriction fragment length polymorphism of the apoA-I/C-III/A-IV locus was examined in French Canadians. The data do not differentiate between the effects of the Xmn I restriction fragment length polymorphism and the A substitution.

In a further effort to distinguish between A alleles that do and do not confer high plasma HDL-C levels, we identified suballeles with a polymorphic dinucleotide repeat in intron 3 of the apoC-III gene.²⁴ To overcome the large amount of allelic polymorphism we observed in our sample of unrelated French Canadians (data not shown), we studied four families in which the A allele was introduced more than once. In each family evidence was presented for an A allele that segregated with hyperalphalipoproteinemia and one with no apparent effects on HDL-C levels. Although these analyses were perhaps limited by the small number of carriers of a specific A allele within one family, the data support the hypothesis that only a subset of A alleles confers high HDL-C levels.

The present study presents three lines of evidence that the observed association of the GA substitution in the apoA-I gene promoter, with its high plasma apoA-I and HDL-C levels, is unlikely to result from a direct effect of this polymorphism on HDL metabolism. First, no gene-dosage effect was detected. Second, HDL-C levels among men and women with the A allele were bimodally distributed with one peak corresponding to the sample mean and a second corresponding to higher levels. Finally, within each of four families, hyperalphalipoproteinemia segregated with only a subset of A alleles. One possible explanation for these results is that some A alleles contain additional sequences that confer a negative effect on HDL-C levels. More likely, however, is that for a subset of alleles, the A substitution is in linkage disequilibrium with other sequences at the apoA-I/C-III/A-IV locus that raise HDL-C levels. Elucidation and analysis of sequence difference(s) between the different A alleles will address this possibility.

	Selected Abbreviations and Acronyms

 

A+ = carriers of the A allele A- = noncarriers of the A allele HDL-C = HDL cholesterol TG = triglycerides

	Acknowledgments

 
This work was supported by grants from the MRC/CIBA-GEIGY/Clinical Research Institute of Montreal University Industry program (UI-11407), the J.A. deSève Foundation, and Health and Welfare, Canada (No. 6605-2087-52). We are indebted to Drs Charles Sing and Ken Weiss for assistance in statistical analysis of frequency distributions. We thank Drs Jonathan Cohen, Madeleine Roy, and Christine Bétard for critical reading of the manuscript. We are also grateful to Ann Chamberland for technical assistance.

Received March 16, 1995; accepted July 19, 1995.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Funke H, von Eckardstein A, Pritchard PH, Karas M, Albers JJ, Assmann G. A frameshift mutation in the human apoA-I gene causes HDL deficiency, partial L:CAT deficiency, and corneal opacities. J Clin Invest. 1991;87:371-376.
2. Karathanasis SK, Ferris E, Haddad IA. DNA inversion within the apolipoproteins AI/CIII/AIV-encoding gene cluster of certain patients with premature atherosclerosis. Proc Natl Acad Sci U S A. 1987;84:7198-7202. [Abstract/Free Full Text]
3. Hamsten A, Iselius L, Dahlen G, de Faire U. Genetic and cultural inheritance of serum lipids, low and high density lipoprotein cholesterol and serum apolipoproteins A-I, A-II and B. Atherosclerosis. 1986;60:199-208. [Medline] [Order article via Infotrieve]
4. Kuusi T, Kesaniemi YA, Vuoristo M, Miettinen TA, Koskenvuo M. Inheritance of high-density lipoprotein and lipoprotein lipase and hepatic lipase activity. Arteriosclerosis. 1987;7:421-425. [Abstract/Free Full Text]
5. Cohen JC, Wang Z, Grundy SM, Stoesz MR, Guerra R. Variation at the hepatic lipase and apolipoprotein AI/CIII/AIV loci is a major cause of genetically determined variation in plasma HDL cholesterol levels. J Clin Invest. 1994;94:2377-2384.
6. Jeenah M, Kessling A, Miller N, Humphries SE. G to A substitution in the promoter region of the apolipoprotein AI gene is associated with elevated serum apolipoprotein AI and high density lipoprotein cholesterol concentrations. Mol Biol Med. 1990;7:233-241. [Medline] [Order article via Infotrieve]
7. Pagani F, Sidoli A, Giudici GA, Barenghi L, Vergani C, Baralle FE. Human apolipoprotein A-I gene promoter polymorphism: association with hyperalphalipoproteinemia. J Lipid Res. 1990;31:1371-1377. [Abstract]
8. Paul-Hayase H, Rosseneu M, Robinson D, Van Bervliet JP, Deslypere JP, Humphries SE. Polymorphisms in the apolipoprotein (apo) AI-CIII-AIV gene cluster: detection of genetic variation determining plasma apo AI, apo CIII and apo AIV concentrations. Hum Genet. 1992;88:439-446. [Medline] [Order article via Infotrieve]
9. Smith JD, Brinton EA, Breslow JL. Polymorphism in the human apolipoprotein A-I gene promoter region: association of the minor allele with decreased production rate in vivo and promoter activity in vitro. J Clin Invest. 1992;89:1796-1800.
10. Tuteja R, Tuteja N, Melo C, Casari G, Baralle FE. Transcription efficiency of human apolipoprotein A-I promoter varies with naturally occurring A to G transition. FEBS Lett. 1992;304:98-101. [Medline] [Order article via Infotrieve]
11. Angotti E, Mele E, Costanzo F, Avvedimento EV. A polymorphism (GA transition) in the -78 position of the apolipoprotein A-I promoter increases transcription efficiency. J Biol Chem. 1994;269:17371-17374. [Abstract/Free Full Text]
12. Barre DE, Guerra R, Verstraete R, Wang Z, Grundy SM, Cohen JC. Genetic analysis of a polymorphism in the human apolipoprotein A-I gene promoter: effect on plasma HDL-cholesterol levels. J Lipid Res. 1994;35:1292-1296. [Abstract]
13. Betard C, Kessling A, Roy M, Chamberland A, Lussier-Cacan S, Davignon J. Molecular genetic evidence for a founder effect in familial hypercholesterolemia among French-Canadians. Hum Genet. 1992;88:529-536. [Medline] [Order article via Infotrieve]
14. Davignon J. Familial hypercholesterolemia in French-Canadians: taking advantage of the presence of a founder effect. Am J Cardiol. 1993;72:6D-10D. [Medline] [Order article via Infotrieve]
15. Xhignesse M, Lussier-Cacan S, Sing C, Kessling AM, Davignon J. Influences of common variants of apolipoprotein E on measures of lipid metabolism in a sample selected for health. Arterioscler Thromb. 1991;11:1100-1110. [Abstract/Free Full Text]
16. Hobbs HH, Brown MS, Russell DW, Davignon J, Goldstein JL. Deletion in the gene for the LDL receptor in majority of French Canadians with familial hypercholesterolemia. N Engl J Med. 1987;317:734-737. [Abstract]
17. Tybjærg-Hansen A, Humphries SE. Familial defective apolipoprotein B-100: a single mutation that causes hypercholesterolemia and premature coronary artery disease. Atherosclerosis. 1992;96:91-107.[Medline] [Order article via Infotrieve]
18. Rauh G, Keller C, Schuster H, Wolfram G, Zollner N. Familial defective apolipoprotein B-100: a common cause of primary hypercholesterolemia. Clin Invest. 1992;70:77-84. [Medline] [Order article via Infotrieve]
19. Innerarity TL, Mahley RW, Weisgraber KH, Bersot TP, Krauss RM, Vega GL, Grundy SM, Friedl W, Davignon J, McCarthy BJ. Familial defective apolipoprotein B-100: a mutation of apolipoprotein B that causes hypercholesterolemia. J Lipid Res. 1990;31:1337-1349. [Abstract]
20. Lipid Research Clinics Program. Manual of Laboratory Operations, I. Washington, DC: US Government Printing Office; 1974.
21. Gidez CI, Miller GJ, Burstein M, Slage S, Eder HA. Separation and quantification of subclasses of human plasma high density lipoproteins by a simple precipitation procedure. J Lipid Res. 1982;23:1206-1223. [Abstract]
22. Saiki RK, Gelfand DH, Stoffel S, Sharf SJ, Higuchi R, Norn GT, Mullis KB, Erlich HA. Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science. 1988;239:487-491. [Abstract/Free Full Text]
23. Shoulders CC, Narcisi TME, Jarmuz A, Brett DJ, Bayliss JD, Scott J. Characterization of genetic markers in the 5' flanking region of the apo A1 gene. Hum Genet. 1993;91:197-198. [Medline] [Order article via Infotrieve]
24. Bhattacharya S, Wilson TME, Wojciechowski AP, Volpe CP, Scott J. Hypervariable polymorphism in the APOC3 gene. Nucleic Acids Res. 1991;19:4799. [Free Full Text]
25. Sokal RR, Rohlf FJ. Biometry. New York, NY: WH Freeman and Co; 1981:174.
26. Day NE. Estimating the components of a mixture of normal distributions. Biometrika. 1969;56:463-474. [Abstract/Free Full Text]
27. Sigurdsson G Jr, Gudnason V, Sigurdsson G, Humphries SE. Interaction between a polymorphism of the apo A-I promoter region and smoking determines plasma levels of HDL and apo A-I. Arterioscler Thromb. 1992;12:1017-1022. [Abstract/Free Full Text]
28. Kessling AM, Horsthemke B, Humphries SE. A study of DNA polymorphisms around the apolipoprotein AI gene in hyperlipidemic and normal individuals. Clin Genet. 1985;28:296-306. [Medline] [Order article via Infotrieve]
29. Lander ES, Schork NJ. Genetic dissection of complex traits. Science. 1994;265:1981-2144.
30. Rozen R, De Braekeleer M, Daigneault J, Ferreira-Rajabi L, Gerdes M, Lamoureux L, Aubin G, Simard F, Fujwara TM, Morgan K. Cystic fibrosis mutations in French Canadians: three CFTR mutations are relatively frequent in a Quebec population with an elevated incidence of cystic fibrosis. Am J Med Genet. 1992;42:360-364. [Medline] [Order article via Infotrieve]
31. Kaplan F, Kokotsis G, DeBraekeleer M, Morgan K, Scriver CR. Beta-thalassemia genes in French-Canadians: haplotype and mutation analysis of Portneuf chromosomes. Am J Hum Genet. 1990;46:126-132. [Medline] [Order article via Infotrieve]
32. De Braekeleer M, Dallaire A, Mathieu J. Genetic epidemiology of sensorimotor polyneuropathy with or without agenesis of the corpus callosum in northeastern Quebec. Hum Genet. 1993;91:223-227. [Medline] [Order article via Infotrieve]
33. De Braekeleer M, Giasson F, Mathieu J, Roy M, Bouchard JP, Morgan K. Genetic epidemiology of autosomal recessive spastic ataxia of Charlevoix-Saguenay in northeastern Quebec. Genet Epidemiol. 1993;10:17-25. [Medline] [Order article via Infotrieve]
34. Mathieu J, De Braekeleer M, Prévost C. Genealogical reconstruction of myotonic dystrophy in the Saguenay-Lac-Saint-Jean area (Quebec, Canada). Neurology. 1990;40:839-842. [Abstract/Free Full Text]
35. Talmud PJ, Ye S, Humphries SE. Polymorphism in the promoter region of the apolipoprotein AI gene associated with differences in apolipoprotein AI levels: the European Atherosclerosis Research Study. Genet Epidemiol. 1994;11:265-280.[Medline] [Order article via Infotrieve]

This article has been cited by other articles:

				J. M Ordovas Genetic interactions with diet influence the risk of cardiovascular disease Am. J. Clinical Nutrition, February 1, 2006; 83(2): 443S - 446S. [Abstract] [Full Text] [PDF]

				Q. Yang, C.-Q. Lai, L. Parnell, L. A. Cupples, X. Adiconis, Y. Zhu, P. W. F. Wilson, D. E. Housman, A. M. Shearman, R. B. D'Agostino, et al. Genome-wide linkage analyses and candidate gene fine mapping for HDL3 cholesterol: the Framingham Study J. Lipid Res., July 1, 2005; 46(7): 1416 - 1425. [Abstract] [Full Text] [PDF]

				J. M Ordovas, D. Corella, L A. Cupples, S. Demissie, A. Kelleher, O. Coltell, P. W. Wilson, E. J Schaefer, and K. Tucker Polyunsaturated fatty acids modulate the effects of the APOA1 G-A polymorphism on HDL-cholesterol concentrations in a sex-specific manner: the Framingham Study Am. J. Clinical Nutrition, January 1, 2002; 75(1): 38 - 46. [Abstract] [Full Text] [PDF]

				W. Huang, J. Sasaki, A. Matsunaga, H. Nanimatsu, K. Moriyama, H. Han, M. Kugi, T. Koga, K. Yamaguchi, and K. Arakawa A Novel Homozygous Missense Mutation in the Apo A-I Gene With Apo A-I Deficiency Arterioscler. Thromb. Vasc. Biol., March 1, 1998; 18(3): 389 - 396. [Abstract] [Full Text] [PDF]

This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Minnich, A. Articles by Davignon, J. Search for Related Content PubMed PubMed Citation Articles by Minnich, A. Articles by Davignon, J.