title: Effect of the melanocortin-3 receptor C17A and G241A variants on weight loss in childhood obesity.
abstract: BACKGROUND
  The central melanocortin system is critical for the long-term regulation of energy homeostasis. Melanocortin-3 receptor (MC3R) knock-out mice, despite being hypophagic, have increased fat mass and higher feed efficiency than do their wild-type littermates.
  
  
  OBJECTIVE
  The aim was to evaluate whether, in childhood obesity, MC3R variants are associated with changes in fatness reduction as a consequence of a weight-reduction program.
  
  
  METHODS
  Molecular screening of the MC3R coding region in 184 obese children, 77 girls and 107 boys [x (+/-SEM) body mass index (BMI; in kg/m(2)) z score: 3.3 +/- 2.3; age 9.2 +/- 2 y], was performed. BMI was evaluated at baseline and after 6 and 12 mo of the weight loss program.
  
  
  RESULTS
  No new mutations were found. Two previously described polymorphisms, C17A (Thr6Lys) and G241A (Val81Ile), were observed in 20 patients in almost complete linkage disequilibrium. No significant differences in BMI z scores were observed at baseline of the weight-loss program between the genotypes; however, at follow-up, heterozygotes showed a significantly higher BMI z score (P = 0.03). When the patients were divided according to the amount of weight lost, a higher prevalence of heterozygotes was observed among subjects who lowered their BMI z score <1.5 (P = 0.03).
  
  
  CONCLUSIONS
  These results suggest a gene-diet interaction between the MC3R C17A and G241A variants and a weight loss program for the ability to lose weight in childhood obesity.
authors.affiliation: Department of Pediatrics "F Fede," Seconda Università degli Studi di Napoli, Napoli, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Santoro
authors.forename: Laura
authors.initials: L
authors.lastname: Perrone
authors.forename: Grazia
authors.initials: G
authors.lastname: Cirillo
authors.forename: Paolo
authors.initials: P
authors.lastname: Raimondo
authors.forename: Alessandra
authors.initials: A
authors.lastname: Amato
authors.forename: Carmine
authors.initials: C
authors.lastname: Brienza
authors.forename: Emanuele Miraglia
authors.initials: EM
authors.lastname: Del Giudice
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D001823:Body Composition / Q000235:genetics* / Q000502:physiology; D002648:Child; D004038:Diet, Reducing; D005260:Female; D005820:Genetic Testing; D014644:Genetic Variation; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D009765:Obesity / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D044104:Receptor, Melanocortin, Type 3 / Q000235:genetics*; D015431:Weight Loss / Q000235:genetics / Q000502:physiology
chemical_list: D044104:Receptor, Melanocortin, Type 3