Quantitative trait loci for abdominal fat and BMI in Hispanic-Americans and African-Americans: the IRAS Family study.
OBJECTIVE
To conduct linkage analysis for body mass index (BMI, kg/m2), waist-to-hip ratio (WHR), visceral adipose tissue mass (VAT, cm2) and subcutaneous adipose tissue mass (SAT, cm2) using a whole genome scan.


METHODS
Cross-sectional family study.


METHODS
African-American families from Los Angeles (AA, n=21 extended pedigrees) and Hispanic-American families (HA) from San Antonio, TX (HA-SA, n=33 extended pedigrees) and San Luis Valley, CO (HA-SLV, n=12 extended pedigrees), totaling 1049 individuals in the Insulin Resistance and Atherosclerosis (IRAS) Family Study.


METHODS
VAT and SAT were measured using a computed tomography scan obtained at the fourth and fifth lumbar vertebrae. All phenotypes were adjusted for age, gender, and study center. VAT, SAT, and WHR were analyzed both unadjusted and adjusted for BMI.


RESULTS
Significant linkage to BMI was found at D3S2387 (LOD=3.67) in African-Americans, and at D17S1290 in Hispanic-Americans (LOD=2.76). BMI-adjusted WHR was linked to 12q13-21 (D12S297 (LOD=2.67) and D12S1052 (LOD=2.60)) in Hispanic-Americans. The peak LOD score for BMI-adjusted VAT was found at D11S2006 (2.36) in Hispanic families from San Antonio. BMI-adjusted SAT was linked to D5S820 in Hispanic families (LOD=2.64). Evidence supporting linkage of WHR at D11S2006, VAT at D17S1290, and SAT at D1S1609, D3S2387, and D6S1056 was dependent on BMI, such that the LOD scores became nonsignificant after adjustment of these phenotypes for BMI.


CONCLUSIONS
Our findings both replicate previous linkage regions and suggest novel regions in the genome that may harbor quantitative trait locis contributing to variation in measures of adiposity.
Norris
J M
JM
Department of Preventive Medicine and Biometrics, University of Colorado Health Sciences Center, Denver, CO 80262, USA. jill.norris@uchsc.edu
Langefeld
C D
CD
Scherzinger
A L
AL
Rich
S S
SS
Bookman
E
E
Beck
S R
SR
Saad
M F
MF
Haffner
S M
SM
Bergman
R N
RN
Bowden
D W
DW
Wagenknecht
L E
LE
D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000328:Adult; D001741:Black or African American; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D009765:Obesity / Q000000981:diagnostic imaging / Q000235:genetics*; D010641:Phenotype; D019655:Quantitative Trait, Heritable; D014057:Tomography, X-Ray Computed; D049629:Waist-Hip Ratio