A genome-wide scan to find obesity and energy metabolism genes was recently completed. 517 polymorphic microsatellite markers (spacing of 6.4 cM) were typed in 382 Pima Indian siblings for obesity (percent body fat) and 220 siblings for energy metabolism (24-h energy expenditure, resting metabolic rate, respiratory quotient, etc.). By the sib-pair linkage method, regions with LOD scores greater or equal than 2.0 were found at 11q21-q22 for percent body fat (LOD 2.1) 11q23-q24 for 24-hour energy expenditure (LOD=2.0) and 1p31-p21 (LOD=2.0) and 20q11.2 (LOD=3.0) for 24-hour respiratory quotient. An additional region with evidence for linkage to percent fat was detected by the variance component method at 18q12 (LOD=2.3). Possible candidate genes include the leptin receptor at 1p31 and the agouti signaling protein at 20q11.2. We have been phenotyping additional subjects to extend these findings. This project is terminated.
