A novel obesity locus on chromosome 4q: the Strong Heart Family Study.
OBJECTIVE
Obesity is a growing and important public health problem in Western countries and worldwide. There is ample evidence that both environmental and genetic factors influence the risk of developing obesity. Although a number of genes influencing obesity and obesity-related measures have been localized, it is clear that others remain to be identified. The rate of obesity is particularly high in American Indian populations. This study reports the results of a genome-wide scan for loci influencing BMI and weight in 963 individuals in 58 families from three American Indian populations in Arizona, Oklahoma, and North and South Dakota participating in the Strong Heart Family Study.


METHODS
Short tandem repeat markers were genotyped, resulting in a marker map with an average spacing of 10 centimorgans. Standard multipoint variance component linkage methods were used.


RESULTS
Significant evidence of linkage was observed in the overall sample, including all three study sites, for a locus on chromosome 4q35 [logarithm of the odds (LOD)=5.17 for weight, 5.08 for BMI]. Analyses of the three study sites individually showed that the greatest linkage support for the chromosome 4 locus came from Arizona (LOD=2.6 for BMI), but that LOD scores for weight were >1 in all three samples. Suggestive linkage signals (LOD>2) were also observed on chromosomes 5, 7, 8, and 10.


CONCLUSIONS
The chromosome 4 locus detected in this scan is in a region lacking any obvious positional candidate genes with known functions related to obesity. This locus may represent a novel obesity gene.
Almasy
Laura
L
Department of Genetics, Southwest Foundation for Biomedical Research, P.O. Box 760549, San Antonio TX 78245-0549, USA. almasy@sfbrgenetics.org
Göring
Harald H H
HH
Diego
Vincent
V
Cole
Shelley
S
Laston
Sandra
S
Dyke
Bennett
B
Howard
Barbara V
BV
Lee
Elisa T
ET
Best
Lyle G
LG
Devereux
Richard
R
Fabsitz
Richard R
RR
MacCluer
Jean W
JW
D000704:Analysis of Variance; D015992:Body Mass Index; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D005190:Family; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D008126:Lod Score; D008297:Male; D018895:Microsatellite Repeats; D009765:Obesity / Q000235:genetics*; D016133:Polymerase Chain Reaction
D004247:DNA