title: Severe resistance to weight gain, lack of stored triglycerides in adipose tissue, hypoglycaemia, and increased energy expenditure: a novel disorder of energy homeostasis.
abstract: BACKGROUND
  Growth during childhood is a consequence of the equilibrium of energy balance. Obesity results from a shift of the equilibrium towards increased energy intake over expenditure. A clinical description of extreme leanness and failure to thrive secondary to a shift of the equilibrium towards increased energy expenditure over energy intake has not been previously described in the medical literature.
  
  
  METHODS
  We report the case of a female child born premature with a birth weight of 1.1 kg who presented with extreme failure to thrive, persistent hypoglycaemia, paucity of fat in the adipose tissue with increased brown fat and increased resting energy expenditure.
  
  
  RESULTS
  Complete cessation of weight and height was noted between 3 months to 3.5 years of age. Hypoglycaemia was secondary to depleted energy stores and increased insulin sensitivity. Increased resting energy expenditure was demonstrated on indirect calorimetric assessment. Biopsy of adipose tissue demonstrated paucity of stored fat with increase in brown fat. No gain in weight and height was demonstrated despite high calorie intake of enteral and parenteral feeds.
  
  
  CONCLUSIONS
  We describe a unique case of extreme failure to thrive with increased energy expenditure and severe hypoglycaemia. Unravelling the molecular basis of this novel disorder has the potential to provide insights into the prevention of obesity.
authors.affiliation: Department of Endocrinology, Great Ormond Street Hospital for Children NHS Trust, and The Institute of Child Health, University College London, London, UK.
authors.forename: Raja
authors.initials: R
authors.lastname: Padidela
authors.forename: Kate
authors.initials: K
authors.lastname: Bennett
authors.forename: Azizun
authors.initials: A
authors.lastname: Nessa
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wells
authors.forename: Roberto
authors.initials: R
authors.lastname: Aufieri
authors.forename: Chela
authors.initials: C
authors.lastname: James
authors.forename: Virpi V
authors.initials: VV
authors.lastname: Smith
authors.forename: Caroline
authors.initials: C
authors.lastname: Brain
authors.forename: Simon
authors.initials: S
authors.lastname: Eaton
authors.forename: Khalid
authors.initials: K
authors.lastname: Hussain
mesh_terms: D052437:Adipocytes, Brown / Q000378:metabolism / Q000473:pathology; D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D001481:Basal Metabolism; D001827:Body Height; D001835:Body Weight; D002657:Child Development; D004734:Energy Metabolism; D005183:Failure to Thrive / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology*; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000097:blood / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D007333:Insulin Resistance; D012720:Severity of Illness Index; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D014280:Triglycerides