Hypothalamic obesity: from basic mechanisms to clinical perspectives

Despite the diverse nature of obesity, there is compelling genetic, clinical, and experimental evidence that endorses the important contribution of brain circuits to this condition. The hypothalamus contains major regulatory circuits for bodyweight homoeostasis, the deregulation of which can lead to obesity. Although functional perturbation of hypothalamic pathways could lie at the basis of common forms of obesity, the term hypothalamic obesity has been created to define those rare forms of severe obesity where a clear hypothalamic substrate can be identified, either of genetic or acquired origin. An in-depth understanding of the pathogenesis, clinical presentation, and therapeutic targets of hypothalamic obesity relies on the comprehension of the physiological basis of hypothalamic pathways governing bodyweight control, the mechanisms (either genetic or acquired) whereby they are perturbed, and the consequences of such perturbation. In this Review, we provide a synoptic overview of hypothalamic obesity, from basic mechanisms to clinical perspectives, with a major focus on current developments and new avenues for the diagnosis and precise treatment of these rare forms of obesity.