The genetics of human obesity: recent progress.

The risk of becoming obese is higher in some families than in others. The risk (the lambda coefficient) is two to three fold for moderate obesity, but up to five to eight fold for severe obesity. Several genes exhibit mutations that can cause early onset severe obesity. These mutations are rare and account for only a small fraction of the cases of obesity. At this time, more than fifty genes have been shown in various studies to influence the energy balance, nutrient partitioning, or the age of onset of obesity. The results of these studies are generally disappointing and often contradictory. One approach is to scan the genome with a high number of polymorphic markers to identify chromosomal regions harboring genes implicated in the development of obesity. Such studies can be helpful in defining new targets to explore.