Genetics of the ghrelin system.

Ghrelin was originally identified as a growth hormone secretagogue, but later studies suggested that it plays an important role in the regulation of appetite and body weight. The implication of genetic variants of the ghrelin-ghrelin receptor axis in the determination of stature, appetite, body weight, glucose metabolism and eating disorders has been the focus of numerous small and larger studies. More recently, several studies have shown some involvement of ghrelin and growth hormone secretagogue receptor (GHSR) genetic variants in some cancers, or their role in the genetics of immune diseases or addictive behaviour. The overall results suggest that the effects of common genetic variants are lacking or modest, while rare sequence alteration may lead to disease status in individual patients. In this review we summarize the available data on the genetics of ghrelin axis in humans.