In addition to prioritizing causal genes in GWAS loci, an eQTL catalog from multiple human tissues can highlight the relevant tissue(s) of action, evaluate the tissue specificity of GWAS loci, and characterize pleiotropic associations. We demonstrate the value of multitissue data to explore and resolve these issues for the GWAS intronic SNP, rs633185, located in ARHGAP42 (Fig. 9). This GWAS SNP is in high LD (r2 = 0.93) with the best cis-eQTL (rs604723) targeting ARHGAP42, and the best cis-eQTL for a neighboring gene, TMEM133 in tibial artery. Evaluating eQTL significance in all nine tissues shows that although the eQTL’s significance is indeed strongest in tibial artery, several other tissues may merit consideration in exploring the causal function of this locus, such as subcutaneous adipose and skin (Fig. 9, B and C, and fig. S33). This supports the need to explore the genetic basis of disease in the fuller context of a wide range of human tissues. The GTEx eQTLs may also be useful in highlighting the role of noncoding genes in disease risk and other complex traits (fig. S34). We
