Low Copy Number of the AMY1 Locus Is Associated with Early-Onset Female Obesity in Finland

PLoS One. 2015 Jul 1;10(7):e0131883. doi: 10.1371/journal.pone.0131883. eCollection 2015.

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.

Patients: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Body Composition / genetics
  • DNA Copy Number Variations*
  • DNA-Binding Proteins / genetics*
  • Female
  • Finland
  • Gene Dosage
  • Genetic Association Studies
  • Genetic Load*
  • Genetic Predisposition to Disease
  • Humans
  • Male
  • Obesity / genetics*
  • Sex Factors
  • Transcription Factors / genetics*
  • Young Adult

Substances

  • DNA-Binding Proteins
  • MYCBP protein, human
  • Transcription Factors

Grant support

The study was supported by grants from: the Academy of Finland (grant 250780), www.aka.fi, OM; the Folkhälsan Research Foundation, www.folkhalsan.fi, OM; the Finnish Pediatric Research Foundation, www.lastentautientutkimussaatio.fi, OM; the Sigrid Jusélius Foundation, www.sigridjuselius.fi/foundation, OM; the Helsinki University Hospital Research Funds (grant TYH2013336), www.hus.fi, OM; the Nilsson-Ehle Donationerna, www.fysiografen.se, AL; the Stockholm County Council, www.sll.se, AL and OM; the Ingabritt and Arne Lundberg Research Foundation (grant 2014-0023), www.lundbergsstiftelsen.se, JAA; the Swedish Research Council (grants 2012-1526 and 2013-2603), www.vr.se, AL and OM; the Swedish Childhood Cancer Foundation, www.barncancerfonden.se, OM; the Harald och Greta Jeanssons foundation, www.jeanssonsstiftelser.se, AL; the Ulf Lundahls Minnesfond/ the Swedish brain foundation, www.hjarnfonden.se, AL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.