title: Low Copy Number of the AMY1 Locus Is Associated with Early-Onset Female Obesity in Finland.
abstract: BACKGROUND
  The salivary α-amylase locus (AMY1) is located in a highly polymorphic multi allelic copy number variable chromosomal region. A recent report identified an association between AMY1 copy numbers and BMI in common obesity. The present study investigated the relationship between AMY1 copy number, BMI and serum amylase in childhood-onset obesity.
  
  
  METHODS
  Sixty-one subjects with a history of childhood-onset obesity (mean age 19.1 years, 54% males) and 71 matched controls (19.8 yrs, 45% males) were included. All anthropometric measures were greater in the obese; their mean BMI was 40 kg/m2 (range 25-62 kg/m2) compared with 23 kg/m2 in the controls (15-32 kg/m2).
  
  
  RESULTS
  Mean AMY1 copy numbers did not differ between the obese and control subjects, but gender differences were observed; obese men showed the highest and obese women the lowest number of AMY1 copies (p=0.045). Further, only in affected females, AMY1 copy number correlated significantly with whole body fat percent (r=-0.512, p=0.013) and BMI (r=-0.416, p=0.025). Finally, a clear linear association between AMY1 copy number and serum salivary amylase was observed in all subgroups but again differences existed between obese males and females.
  
  
  CONCLUSIONS
  In conclusion, our findings suggest that AMY1 copy number differences play a role in childhood-onset obesity but the effect differs between males and females. Further studies in larger cohorts are needed to confirm these observations.
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Viljakainen
authors.affiliation: Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Center for Cardiovascular and Metabolic Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Andersson-Assarsson
authors.affiliation: Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Miriam
authors.initials: M
authors.lastname: Armenio
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Pekkinen
authors.affiliation: Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Pettersson
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Helena
authors.initials: H
authors.lastname: Valta
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Marita
authors.initials: M
authors.lastname: Lipsanen-Nyman
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Folkhälsan Institute of Genetics, Helsinki, Finland; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Outi
authors.initials: O
authors.lastname: Mäkitie
authors.affiliation: Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Lindstrand
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000235:genetics; D056915:DNA Copy Number Variations; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005387:Finland; D018628:Gene Dosage; D056726:Genetic Association Studies; D040741:Genetic Load; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009765:Obesity / Q000235:genetics*; D012737:Sex Factors; D014157:Transcription Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; C116115:MYCBP protein, human; D014157:Transcription Factors