[Prader-Willi-Labhart syndrome: relations with the hypothalamus and chromosome 15].

The Prader-Willi syndrome is a human disease whose physiological causes have not yet been elucidated. However, clinical and biological parameters suggest that it is an hypothalamic disorder. This syndrome is the most common form of human congenital obesity. In many cases, the genetic alteration has been identified as a microdeletion in the chromosomal region 15q11-q13. Consequently, one can presume that obesity in patients with Prader-Willi syndrome is the result of some hypothalamic deficiency involving the products of one or several genes found in this region of chromosome 15. Several DNA markers belonging to this genomic region have been isolated. If these are fragments of expressed genes, it may be possible to examine the possible association of their products with the hypothalamus and the disease. Such studies may provide new insights into the role of the hypothalamus in the pathophysiology of obesity.