Figure 4

SNPs associated with colonic diseases and type 2 diabetes are enriched for colon cis -eQTL. A simulation-based analysis was performed to test for the enrichment of colon cis-eQTL among SNPs associated with colonic diseases (A) body mass index (BMI), lipid traits and type 2 diabetes (T2D) (B) downloaded from the NHGRI GWAS catalog. The distribution of the number of cis-eQTL in 1,000 simulated SNP sets, each of the same size (n) as the list of trait-associated SNPs and containing SNPs matched on MAF distribution is shown in the histograms. Solid black circles represent the actual cis-eQTL count (cis-eQTL p-value threshold of 0.001) observed in the trait-associated SNPs. The p-values shown are empirical, and are calculated as the proportion of sampled SNP sets in which the cis-eQTL count exceeds the actual count observed in the trait-associated SNPs. Enrichment of cis-eQTL among disease-associated SNPs is statistically significant for all colonic diseases. Enrichment of cis-eQTL is statistically significant for T2D (p = 0.034) and suggestively significant for BMI (p = 0.055). There is no enrichment of cis-eQTL among SNPs associated with lipid traits.