Association between rs12970134 Near <b><i>MC4R</i></b> and Adiposity Indexes in a Homogenous Population of Caucasian Schoolchildren

Abstract

Background: To assess whether previously identified obesity-susceptibility loci were associated with overweight/obesity risk in a homogeneous population of Caucasian schoolchildren and whether these associations varied with age. Methods: Seven hundred and forty-five schoolchildren (353 boys, mean age: 8.3 ± 1.4 years) underwent anthropometric assessments. A saliva sample was collected for DNA extraction and assessment of 19 single-nucleotide polymorphisms previously associated with obesity. Results: Only the rs12970134 in the MC4R gene was significantly associated with overweight/obesity risk, with a higher frequency of the AA risk genotype in children with a BMI >85th (8.3%) than in those with a BMI <85th percentile (3.0%), p = 0.001; odds ratio (95% CI) of 1.544 (1.192-1.998), p = 0.001, after adjusting for age, sex and pubertal stage. BMI standard deviation scores (SDS) and waist-to-height ratio (W/Hr) progressively increased across the rs12970134 genotypes (GG vs. AG vs. AA): BMI SDS, p = 0.004; W/Hr, p = 0.009. When dividing the study population into two groups based on the median age of participants (8.3 years), the differences in BMI SDS and W/Hr across the MC4R genotypes persisted only in children older than 8.3 years. Conclusions: In a population of Caucasian schoolchildren, the rs12970134 MC4Rvariant was significantly associated with excess body weight, particularly in children older than 8 years of age.

Low AMY1 Gene Copy Number Is Associated with Increased Body Mass Index in Prepubertal Boys

“…Genomic DNA was extracted from saliva by QIAmp DNA blood mini kit (Qiagen, Chatsworth, CA) as previously described [ 14 ]. AMY1 gene copy-number was estimated by a duplex quantitative real-time PCR (qPCR) containing two TaqMan assays (Life Technologies), one for AMY1 (Hs07226361_cn, FAM-labeled) and one specific for the reference gene (RNase P, VIC-labeled).…”