title: Associations between uncoupling protein 2, body composition, and resting energy expenditure in lean and obese African American, white, and Asian children.
abstract: BACKGROUND
  Little is known about genes that affect childhood body weight.
  
  
  OBJECTIVE
  The objective of this study was to examine the association between alleles of the mitochondrial uncoupling protein 2 (UCP2) gene and obesity because UCP2 may influence energy expenditure.
  
  
  METHODS
  We related UCP2 genotype to body composition and resting energy expenditure in 105 children aged 6-10 y. Overweight children and nonoverweight children of overweight parents were genotyped for a 45-base pair deletion/insertion (del/ins) in 3'-untranslated region of exon 8 and for an exon 4 C to T transition.
  
  
  RESULTS
  Eighty-nine children were genotyped for the exon 8 allele: 50 children had del/del, 33 had del/ins, and 6 had ins/ins. Mean (+/-SD) body mass index (BMI; in kg/m(2)) was greater for children with del/ins (24.1 +/- 5.9) than for children with del/del (20.4 +/- 4.8; P < 0.001). BMI of ins/ins children (23.7 +/- 7.8) was not significantly different from that of del/ins children. A greater BMI in del/ins children was independent of race and sex. Body composition was also different according to UCP2 genotype. All body circumferences and skinfold thicknesses examined were significantly greater in del/ins than in del/del children. Body fat mass as determined by dual-energy X-ray absorptiometry was also greater in del/ins than in del/del children (P < 0.005). For 104 children genotyped at exon 4, no significant differences in BMI or body composition were found among the 3 exon 4 genotypes. Neither resting energy expenditure nor respiratory quotient were different according to UCP2 exon 4 or exon 8 genotype.
  
  
  CONCLUSIONS
  The exon 8 ins/del polymorphism of UCP2 appears to be associated with childhood-onset obesity. The UCP2/UCP3 genetic locus may play a role in childhood body weight.
authors.affiliation: Unit on Growth and Obesity, Developmental Endocrinology Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892-1862, USA. jy15i@nih.gov
authors.forename: J A
authors.initials: JA
authors.lastname: Yanovski
authors.forename: A L
authors.initials: AL
authors.lastname: Diament
authors.forename: K N
authors.initials: KN
authors.lastname: Sovik
authors.forename: T T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: N G
authors.initials: NG
authors.lastname: Sebring
authors.forename: C H
authors.initials: CH
authors.lastname: Warden
mesh_terms: D044466:Asian People / Q000235:genetics; D044383:Black People / Q000235:genetics; D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D002648:Child; D004734:Energy Metabolism; D005091:Exons; D005260:Female; D005838:Genotype; D006801:Humans; D007473:Ion Channels; D008297:Male; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D009154:Mutation; D009765:Obesity / Q000235:genetics* / Q000503:physiopathology; D011506:Proteins / Q000235:genetics*; D044469:Racial Groups / Q000235:genetics*; D012146:Rest; D000071246:Uncoupling Protein 2; D044465:White People / Q000235:genetics; D001741:Black or African American
chemical_list: D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C000604389:UCP2 protein, human; D000071246:Uncoupling Protein 2