Supplementary Material for: Novel Genetic Loci Associated with the Plasma Triglyceride Response to an Omega-3 Fatty Acid Supplementation

<b><i>Background:</i></b> A recent genome-wide association study (GWAS) by our group identified 13 loci associated with the plasma triglyceride (TG) response to omega-3 (n-3) fatty acid (FA) supplementation. This study aimed to test whether single-nucleotide polymorphisms (SNPs) within the <i>IQCJ, NXPH1, PHF17</i> and <i>MYB</i> genes are associated with the plasma TG response to an n-3 FA supplementation. <b><i>Methods:</i></b> A total of 208 subjects followed a 6-week n-3 FA supplementation of 5 g/day of fish oil (1.9-2.2 g of eicosapentaenoic acid and 1.1 g of docosahexaenoic acid). Measurements of plasma lipids were made before and after the supplementation. Sixty-seven tagged SNPs were selected to increase the density of markers near GWAS hits. <b><i>Results:</i></b> In a repeated model, independent effects of the genotype and the gene-supplementation interaction were associated with plasma TG. Genotype effects were observed with two SNPs of <i>NXPH1</i>, and gene-diet interactions were observed with ten SNPs of <i>IQCJ</i>, four SNPs of <i>NXPH1</i> and three SNPs of <i>MYB</i>. Positive and negative responders showed different genotype frequencies with nine SNPs of <i>IQCJ</i>, two SNPs of <i>NXPH1</i> and two SNPs of <i>MYB</i>. <b><i>Conclusion:</i></b> Fine mapping in GWAS-associated loci allowed the identification of SNPs partly explaining the large interindividual variability observed in plasma TG levels in response to an n-3 FA supplementation.