1137-P: Liver Regulatory Variants and Genes at Metabolic Trait Loci

Genome-wide association studies (GWAS) have identified many loci that affect liver- and lipid-related metabolic traits, but the causal variants, target genes and mechanisms for most loci have not been characterized. GWAS loci are often enriched in tissue-specific transcriptional regulatory elements that drive physiological changes, and loci can be annotated with colocalized molecular quantitative traits for gene expression (eQTL) and accessible chromatin (caQTL) to identify candidate variants and genes. We previously profiled chromatin accessibility in 20 human liver samples, identified caQTL variants that colocalized with GWAS loci for metabolic traits, and predicted target genes based on promoter proximity, Hi-C chromatin contact with a promoter, and co-localization with liver eQTL. Here, we examined selected GWAS loci and tested variants for effects on gene regulation. We prioritized loci based on trait, gene function, and QTL characteristics and selected four variant-gene pairs to study. To evaluate effects of specific variants on gene expression, we performed transcriptional reporter assays in HepG2 cells. Three caQTL variants exhibited significant (P