title: Pathogenesis of the metabolic syndrome: insights from monogenic disorders.
abstract: Identifying rare human metabolic disorders that result from a single-gene defect has not only enabled improved diagnostic and clinical management of such patients, but also has resulted in key biological insights into the pathophysiology of the increasingly prevalent metabolic syndrome. Insulin resistance and type 2 diabetes are linked to obesity and driven by excess caloric intake and reduced physical activity. However, key events in the causation of the metabolic syndrome are difficult to disentangle from compensatory effects and epiphenomena. This review provides an overview of three types of human monogenic disorders that result in (1) severe, non-syndromic obesity, (2) pancreatic beta cell forms of early-onset diabetes, and (3) severe insulin resistance. In these patients with single-gene defects causing their exaggerated metabolic disorder, the primary defect is known. The lessons they provide for current understanding of the molecular pathogenesis of the common metabolic syndrome are highlighted.
authors.affiliation: Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand. r.murphy@auckland.ac.nz
authors.forename: Rinki
authors.initials: R
authors.lastname: Murphy
authors.forename: Richard W
authors.initials: RW
authors.lastname: Carroll
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Krebs
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D024821:Metabolic Syndrome / Q000378:metabolism* / Q000473:pathology*; D008954:Models, Biological; D009765:Obesity / Q000378:metabolism / Q000473:pathology