Genomic scan for genes affecting body composition before and after training in Caucasians from HERITAGE

An autosomal genomewide search for genes related to body composition and it s changes after a 20-wk endurance-exercise training program has been comple ted in the HERITAGE Family Study. Phenotypes included body mass index (BMI) , sum of eight skinfold thicknesses, fat mass (FM), fat-free mass, percent body fat (% Fat), and plasma leptin levels. A maximum of 364 sib-pairs from 99 Caucasian families was studied with the use of 344 markers with single- point and multipoint linkage analyses. Evidence of significant linkage was observed for changes in fat-free mass with the S100A and the insulin-like g rowth factor I genes (P = 0.0001). Suggestive evidence (2.0 less than or eq ual to Lod < 3.0; 0.0001 < P less than or equal to 0.001) was also observed for the changes in FM and %Fat at 1q31 and 18q21-q23, in %Fat with the unc oupling protein 2 and 3 genes, and in BMI at 5q14-q21. At baseline, suggest ive evidence was observed for BMI at 8q23-q24, 10p15, and 14q11; for FM at 14q11; and for plasma leptin levels with the low-density lipoprotein recept or gene. This is the first genomic scan on genes involved in exercise-train ing-induced changes in body composition that could provide information on t he determinants of weight loss.