title: Ethnic differentiation of copy number variation on chromosome 16p12.3 for association with obesity phenotypes in European and Chinese populations.
abstract: OBJECTIVE
  Genomic copy number variations (CNVs) have been strongly implicated as important genetic factors for obesity. A recent genome-wide association study identified a novel variant, rs12444979, which is in high linkage disequilibrium with CNV 16p12.3, for association with obesity in Europeans. The aim of this study was to directly examine the relationship between the CNV 16p12.3 and obesity phenotypes, including body mass index (BMI) and body fat mass.
  
  
  METHODS
  Subjects were a multi-ethnic sample, including 2286 unrelated subjects from a European population and 1627 unrelated Han subjects from a Chinese population. Body fat mass was measured using dual energy X-ray absorptiometry.
  
  
  RESULTS
  Using Affymetrix Genome-Wide Human SNP Array 6.0, we directly detected CNV 16p12.3, with the deletion frequency of 27.26 and 0.8% in the European and Chinese populations, respectively. We confirmed the significant association between this CNV and obesity (BMI: P=1.38 × 10(-2); body fat mass: P=2.13 × 10(-3)) in the European population. Less copy numbers were associated with lower BMI and body fat mass, and the effect size was estimated to be 0.62 (BMI) and 1.41 (body fat mass), respectively. However, for the Chinese population, we did not observe significant association signal, and the frequencies of this deletion CNV are quite different between the European and Chinese populations (P<0.001).
  
  
  CONCLUSIONS
  Our findings first suggest that CNV 16p12.3 might be ethnic specific and cause ethnic phenotypic diversity, which may provide some new clues into the understanding of the genetic architecture of obesity.
authors.affiliation: Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.
authors.forename: T-L
authors.initials: TL
authors.lastname: Yang
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: S M
authors.initials: SM
authors.lastname: Li
authors.forename: S K
authors.initials: SK
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Tian
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Liu
authors.forename: H-W
authors.initials: HW
authors.lastname: Deng
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000328:Adult; D044466:Asian People / Q000235:genetics*; D015992:Body Mass Index; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D056915:DNA Copy Number Variations / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology* / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics*