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Lessons from extreme human obesity: monogenic disorders
Sayali A Ranadive1, Christian Vaisse
1Department of Pediatrics, Division of Endocrinology, University of California San Francisco, 513 Parnassus Avenue, Room S672D, San Francisco, CA 94143-0434, USA.
Endocrinology and Metabolism Clinics of North America
|September 9, 2008
Summary
Genetic factors significantly influence human obesity. Studies of rare single-gene disorders reveal the critical role of the hypothalamic leptin-melanocortin system in body weight regulation, though these account for a small fraction of severe cases.
Area of Science:
- Genetics
- Endocrinology
- Metabolism
Background:
- Human obesity is a complex condition with a significant genetic influence.
- The specific genes contributing to common obesity remain largely unidentified.
- Monogenic obesity disorders offer insights into critical pathways regulating body weight.
Purpose of the Study:
- To explore the genetic underpinnings of human obesity.
- To highlight the role of the hypothalamic leptin-melanocortin system in energy balance.
- To understand the genetic heterogeneity contributing to severe obesity.
Main Methods:
- Analysis of extreme human obesity cases resulting from single gene defects.
- Investigation of the hypothalamic leptin-melanocortin pathway's function in energy homeostasis.
- Genetic and mechanistic studies of monogenic obesity disorders.
Main Results:
- Monogenic obesity disorders confirm the essential role of the hypothalamic leptin-melanocortin system in human energy balance.
- Disruptions in this pathway lead to the most severe obesity phenotypes.
- Identified genes and mechanisms in monogenic obesity account for less than 5% of severe obesity cases.
Conclusions:
- The genetic basis of human obesity is highly heterogeneous.
- Numerous genes likely contribute to obesity through various, yet undiscovered, molecular mechanisms.
- Further research is needed to elucidate the full spectrum of genetic factors in obesity.
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