title: APOC1 T45S polymorphism is associated with reduced obesity indices and lower plasma concentrations of leptin and apolipoprotein C-I in aboriginal Canadians.
abstract: Apolipoprotein (apo) C-I is a constituent of chylomicrons, very low density lipoprotein, and high density lipoprotein. The role of apo C-I in human metabolism is incompletely defined. We took advantage of a naturally occurring amino acid polymorphism that is present in aboriginal North Americans, namely apo C-I T45S. We assessed the hypothesis that metabolic traits, including obesity-related and lipoprotein-related traits, would differ between carriers and noncarriers of apo C-I T45S. A genotyping assay was developed for APOC1 T45S and genotypes were determined in a sample of 410 Canadian Oji-Cree subjects. The allele frequency of the apo C-I S45 allele was approximately 8% in this sample. We observed the apo C-I S45 allele was significantly associated with 1) lower percent body fat (P < 0.05), 2) lower waist circumference (P = 0.058), 3) lower serum leptin levels (P < 0.05), and 4) lower plasma apo C-I levels (P < 0.0001), using a newly developed ELISA-based method. Taken together, these results suggest that at the whole human phenotype level, apo C-I is associated with the complex metabolic trait of obesity as well as with serum leptin levels.
authors.affiliation: Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
authors.forename: Piya
authors.initials: P
authors.lastname: Lahiry
authors.forename: Henian
authors.initials: H
authors.lastname: Cao
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Ban
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Pollex
authors.forename: Mary
authors.initials: M
authors.lastname: Mamakeesick
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
authors.forename: Stewart B
authors.initials: SB
authors.lastname: Harris
authors.forename: Anthony J G
authors.initials: AJ
authors.lastname: Hanley
authors.forename: Murray W
authors.initials: MW
authors.lastname: Huff
authors.forename: Philip W
authors.initials: PW
authors.lastname: Connelly
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hegele
mesh_terms: D000293:Adolescent; D000328:Adult; D053302:Apolipoprotein C-I / Q000097:blood* / Q000235:genetics*; D001823:Body Composition; D002170:Canada; D002648:Child; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D006801:Humans; D015228:Hypertriglyceridemia / Q000453:epidemiology; D007198:Indians, North American / Q000235:genetics*; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood / Q000235:genetics*; D056128:Obesity, Abdominal / Q000453:epidemiology; D011110:Polymorphism, Genetic; D015995:Prevalence; D012727:Sex Characteristics; D055105:Waist Circumference; D055815:Young Adult
chemical_list: C505803:APOC1 protein, human; D053302:Apolipoprotein C-I; D020738:Leptin