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

• Published in: PloS one Vol. 10; no. 7; p. e0131883
• Main Authors: Viljakainen, Heli, Andersson-Assarsson, Johanna C, Armenio, Miriam, Pekkinen, Minna, Pettersson, Maria, Valta, Helena, Lipsanen-Nyman, Marita, Mäkitie, Outi, Lindstrand, Anna
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.07.2015; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Amylases; Anthropometry; Body Composition - genetics; Body fat; Body mass; Cardiology and Cardiovascular Disease; Children; Copy number; DNA Copy Number Variations; DNA methylation; DNA-Binding Proteins - genetics; Female; Females; Finland; FRAMESHIFT MUTATION; Gender aspects; GENE; Gene Dosage; Genetic Association Studies; Genetic Load; Genetic Predisposition to Disease; GENOME; Glucose; HUMANS; INSULIN-RESISTANCE; Kardiologi och kardiovaskulära sjukdomar; Loci; Male; Males; MC4R; Multidisciplinary Sciences; Obesity; Obesity - genetics; RISK; Sex differences; Sex Factors; Studies; Subgroups; Transcription Factors - genetics; US ADOLESCENTS; Young Adult; α-Amylase; Finland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0131883

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. 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). 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. 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.