Influence of genetic variants in FADS2 and ELOVL2 genes on BMI and PUFAs homeostasis in children and adolescents with obesity

Several studies identified genetic variants in FADS and ELOVL2 genes associated with obesity-related conditions, such as alterations in blood lipid parameters and insulin homeostasis. The aim of this cross-sectional study was to determine whether FADS and ELOVL2 genetic variants were associated with obesity and adiposity, besides dyslipidaemia and insulin resistance, in a large sample of obese children and adolescents. One thousand six hundred and forty-nine obese children underwent physical examination, anthropometry, fasting blood tests measuring plasma glucose, lipid and liver profile. Two genetic variants were genotyped: rs2236212 in ELOVL2 gene and rs1535 in FADS2, for the gene cluster FADS. In a subgroup of obese children (n = 105), erythrocyte fatty acid composition was measured. Generalized linear models were used to assess association between genotypes and variables. A positive association between zBMI and the minor allele of rs2236212 (p = 0.028), the major allele of rs1535 (p = 0.046) and the genetic score (p = 0.008), created by summing up both risk alleles, were found. The estimation of enzymatic activity revealed that minor alleles were associated significantly with a reduction of the enzymatic activity of elongase and desaturase (p = 0.048 and p = 0.0001, respectively). Common variants in the FADS2 and ELOVL2 genes were associated with BMI in a large population of obese Italian children. These SNPs were associated with alterations in LC-PUFAs homeostasis, not accompanied by modifications of plasma lipids or HOMA-IR. These findings provide additional support to the genetics accounting for BMI interindividual variability and the molecular basis of obesity.