ETIOLOGY OF MASSIVE OBESITY - ROLE OF GENETIC-FACTORS

It is well established that there is a significant familial aggregatio n of obesity, although most of the evidence regarding the genetic basi s of obesity has been derived from overweight and moderately obese cas es. Less is known about the contribution of genetic factors in severel y obese individuals. This paper reviews the available evidence regardi ng the extent of familial aggregation of morbid obesity and the contri bution of specific genes. The results of available studies suggest a s tronger degree of familial resemblance for morbid obesity [body mass i ndex (BMI > 40 kg/m(2))] than for more moderate levels of obesity (BMI < 40 kg/m(2)). Evidence from human association and linkage studies, p erformed with markers surrounding human homologs of the genes involved in mouse models of obesity, revealed that these genes tend to be link ed more often to severe obesity than to moderate levels of obesity.