Low Salivary Amylase Gene (AMY1) Copy Number Is Associated with Obesity and Gut Prevotella Abundance in Mexican Children and Adults

Abstract

Genome-wide association studies (GWAS) have identified copy number variants (CNVs) associated with obesity in chromosomal regions 1p31.1, 10q11.22, 11q11, 16p12.3, and recently 1p21.1, which contains the salivary amylase gene (AMY1). Recent evidence suggests this enzyme may influence gut microbiota composition through carbohydrate (mainly starch) degradation. The role of these CNVs in obesity has been scarcely explored in the Latino population, and thus the aim of our study was to evaluate the association of 1p31.1, 10q11.22, 11q11, 16p12.3 and 1p21.1 CNVs with obesity in 921 Mexican children, to replicate significant associations in 920 Mexican adults, and to analyze the association of AMY1 copy number with gut microbiota in 75 children and 45 adults. Of the five CNVs analyzed, 1q11 CNV was significantly associated with obesity in children, but not in adults. Only AMY1 CNV was significantly associated with obesity in both age groups. Moreover, gut microbiota analyses revealed a positive correlation between AMY1 copy number and Prevotella abundance. This genus has enzymes and gene clusters essential for complex polysaccharide degradation and utilization. To our knowledge, this is the first study to analyze the association of these five CNVs in the Mexican population and to report a correlation between AMY1 CN and gut microbiota in humans.

Low AMY1 Copy Number Is Cross‐Sectionally Associated to an Inflammation‐Related Lipidomics Signature in Overweight and Obese Individuals

“…Although we had the same division for the low AMY1 group, their high AMY1 group included only participants with ≥8 copy numbers. As overweight/obese subjects have lower AMY1 copy numbers, [ 2,6,8 ] this could explain the lower median observed in our population.…”

“…[ 2,4 ] Hence, reduced AMY1 copy numbers have also been associated with increased body mass index (BMI), obesity and cardiovascular risk, IR, and inflammation in both adults and children. [ 2–8 ] However, the association between the AMY1 copy number and obesity has been challenged by recent studies that have found no significant associations despite having a strong statistical power. [ 9–12 ] These conflicting results could be partially attributed to differences in the starch intake.…”

<p>Salivary Amylase Gene Copy Number Is Associated with the Obesity and Inflammatory Markers in Children</p>

“…9,10 The genetic connection between AMY1 CNV and obesity showed that low AMY1 copy number significantly associated with high BMI. 4,5,[11][12][13] Recently from our lab, we showed the inverse association of AMY1 copy number and the obesity measurement in children. 13 Falchi et al first reported the association of AMY1 CNV and the high risk of obesity in a longitudinal study.…”

High plasma salivary α-amylase, but not high AMY1 copy number, associated with low obesity rate in Qatari adults: cross-sectional study

“…body mass index (BMI) and waist circumference 7,[12][13][14][15][16][17][18][19][20][21] . However, other studies reported no association [22][23][24] or a positive association between AMY1 gene CN and BMI 25 .…”