Expression quantitative trait loci (eQTLs) have become a common tool to interpret the regulatory mechanisms of variants identified by genome-wide association studies (GWAS). In particular, cis-eQTLs, where gene expression levels are affected by a gene-proximal (<1 megabases; Mb) single nucleotide polymorphism (SNP), have been widely used for this purpose. However, cis-eQTLs generally explain only a modest proportion of disease heritability1, suggesting additional routes to disease.
