title: Effects of intragenic variability at 3 polymorphic sites of the apolipoprotein B gene on serum lipids and lipoproteins in a multiethnic Asian population.
abstract: We determined the allelic (X+/X-, M+/M-, and E+/E-) distribution frequencies of the XbaI, MspI, and EcoRI restriction fragment length polymorphisms (RFLPs) in the apolipoprotein B gene in a control group of 374 healthy Chinese, Malays, and Indians and in a hyperlipidemic cohort of 131 Chinese patients. Covariability between the RFLPs and serum lipid, lipoprotein, and apolipoprotein concentrations was also studied. We found a lower frequency (average 0.0829) of the X+ allele and higher frequencies of the E+ (average 0.9452) and M+ (average 0.9772) alleles in our study population compared with frequencies reported in other populations. The 3 polymorphic sites did not contribute to significant variations in lipid levels (p > 0.1 in all cases). Also, there was no significant variation in genotype frequencies between the control subjects and the hyperlipidemic subjects. Despite their relative close proximity within the APOB gene sequence, the 3 polymorphic sites did not show any significant linkage disequilibrium. However, the presence of the X+ cutting site was in linkage disequilibrium with the Del allele of the 5' insertion-deletion polymorphism and the E-allele was in linkage disequilibrium with the 3' VNTR located near the 3' end of the coding region of the APOB gene.
authors.affiliation: Department of Pathology, National University of Singapore, Singapore.
authors.forename: M L
authors.initials: ML
authors.lastname: Choong
authors.forename: S K
authors.initials: SK
authors.lastname: Sethi
authors.forename: E S
authors.initials: ES
authors.lastname: Koay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D001055:Apolipoproteins B / Q000097:blood / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D005260:Female; D005787:Gene Frequency; D008040:Genetic Linkage; D014644:Genetic Variation; D005828:Genetics, Population; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology / Q000235:genetics*; D007194:India / Q000208:ethnology; D008055:Lipids / Q000097:blood / Q000235:genetics; D008074:Lipoproteins / Q000097:blood / Q000235:genetics; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012846:Singapore / Q000453:epidemiology
chemical_list: D001055:Apolipoproteins B; D008055:Lipids; D008074:Lipoproteins