Prader-Willi and other syndromes associated with obesity and mental retardation.

[cohen syndrome]

Constitutional obesity and mental retardation cooccur in several multiple congenital anomaly syndromes , including Prader-Willi syndrome , Bardet-Biedl syndrome , Cohen syndrome , Albright hereditary osteodystrophy , and Borjeson-Forssman-Lehmann syndrome as well as some rarer disorders . Although hypothalamic -pituitary axis abnormalities are thought to be a possible causative mechanism in some of these disorders , current knowledge is insufficient to explain the pathophysiologic mechanism of obesity in most multiple congenital anomaly /mental retardation syndromes . The chromosomal location of many of these syndromes is known , and studies are ongoing to identify the causative genes . Further delineation of the functions of the underlying genes will likely be instructive regarding mechanisms of appetite , satiety , and obesity in the general population . This review details current knowledge of the clinical and molecular genetic findings of multiple congenital anomaly /mental retardation syndromes associated with intrinsic obesity in an effort to delineate causative mechanisms and genetic abnormalities contributing to obesity .