Common and rare alleles in apolipoprotein B contribute to plasma levels of low-density lipoprotein cholesterol in the general population.
BACKGROUND
We have previously shown that rare mutations in the apolipoprotein B gene (APOB) may result in not only severe hypercholesterolemia and ischemic heart disease but also hypocholesterolemia. Despite this, common single-nucleotide polymorphisms (SNPs) in APOB have not convincingly been demonstrated to affect low-density lipoprotein (LDL) cholesterol levels.


OBJECTIVE
We tested the hypothesis that nonsynonymous SNPs in three important functional domains of APOB and APOB tag SNPs predict levels of LDL cholesterol and apolipoprotein B and risk of ischemic heart disease.


METHODS
This was a prospective study with 25 yr 100% follow up, The Copenhagen City Heart Study.


METHODS
The study was conducted in the Danish general population.


METHODS
Participants included 9185 women and men aged 20-80+ yr.


METHODS
Levels of LDL cholesterol and apolipoprotein B and risk of ischemic heart disease and myocardial infarction were measured. The hypothesis was formulated before genotyping.


RESULTS
We genotyped 9185 individuals for APOB T71I (minor allele frequency: 0.33), Ivs4+171c>a (0.14), A591V (0.47), Ivs18+379a>c (0.30), Ivs18+1708g>t (0.45), T2488Tc>t (0.48), P2712L (0.21), R3611Q (0.09), E4154K (0.17), and N4311S (0.21). SNPs were associated with increases (T71I, Ivs181708g>t, T2488Tc>t, R3611) or decreases (Ivs4+171c>a, A591V, Ivs18+379a>c, P2712L, E4154, N4311S) in LDL cholesterol from -4.7 to +8.2% (-0.28 to 0.30 mmol/liter; P<or=0.002), and corresponding effects on cholesterol and apolipoprotein B levels. However, as predicted from the magnitude of the observed LDL cholesterol effects, none of these SNPs predicted risk of ischemic heart disease prospectively in the general population, in a case-control study, or as haplotypes.


CONCLUSIONS
Multiple common and rare alleles in APOB contribute to plasma levels of LDL cholesterol in the general population, although the effects of common alleles and haplotypes are modest.
Benn
Marianne
M
Department of Clinical Biochemistry KB3011, Section for Molecular Genetics, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark.
Stene
Maria C A
MC
Nordestgaard
Børge G
BG
Jensen
Gorm B
GB
Steffensen
Rolf
R
Tybjaerg-Hansen
Anne
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001055:Apolipoproteins B / Q000097:blood / Q000235:genetics*; D008078:Cholesterol, LDL / Q000097:blood*; D005260:Female; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D017202:Myocardial Ischemia / Q000209:etiology; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies
D001055:Apolipoproteins B; D008078:Cholesterol, LDL