BACKGROUND:

Despite intensive efforts the genetic basis of obesity has been difficult to establish. Linkage analysis using a genome-wide scan can potentially identify genomic regions not previously thought to be associated with susceptibility to obesity and provides a comprehensive test of the consistency of previous studies. The study used the considerable resources generated by the four cooperating networks in the NHLBI-supported "Family Blood Pressure Program" (FBPP) to conduct a genome-wide scan data for obesity.

DESIGN NARRATIVE:

In the Family Blood Pressure Program, microsatellite markers were typed at a density of -10cM by the Mammalian Genotyping Service (MGS) in Marshfield, WI. The complete data set was to include 9,940 individuals representing 4 ethnic groups (white, black, Hispanic and Asian). Obesity was characterized as a weight/height ratio (body mass index) and waist/hip ratio. This data set was larger than any prior genome scan for obesity, and the inclusion of multiple ethnic groups made it possible to examine genetic heterogeneity. The specific aims of the study were to conduct linkage and association analyses to localize regions influencing obesity. Investigators worked closely with the FBPP Coordinating Center (Washington University, St. Louis) and investigators from each of the four FBPP networks. Evidence was sought for consistency between results obtained from analyses of the genome scan performed by each of the individuals, and results summarized from the literature, with those found in meta-analysis.