The study aimed to identify the downstream effects of disease-associated single nucleotide polymorphisms (SNPs) by performing expression quantitative trait locus (eQTL) meta-analysis in non-transformed peripheral blood samples from 5,311 individuals, with replication in 2,775 individuals. The researchers identified and replicated trans eQTLs for 233 SNPs (reflecting 103 independent loci) previously associated with complex traits at genome-wide significance. Some of these SNPs affect multiple genes in trans that are known to be altered in individuals with disease, such as rs4917014, which is associated with systemic lupus erythematosus (SLE) and alters the expression of $C1QB$ and five type I interferon response genes. DeepSAGE RNA sequencing and chromatin immunoprecipitation and sequencing analysis implicated $IKZF1$ as the causal gene. Variants associated with cholesterol metabolism and type 1 diabetes also showed similar phenomena, indicating that large-scale eQTL mapping provides insights into the downstream effects of many trait-associated variants. The study highlights the importance of trans eQTLs in understanding the pathogenesis of diseases and suggests that future, larger-scale trans eQTL analyses in blood will uncover more regulatory relationships.The study aimed to identify the downstream effects of disease-associated single nucleotide polymorphisms (SNPs) by performing expression quantitative trait locus (eQTL) meta-analysis in non-transformed peripheral blood samples from 5,311 individuals, with replication in 2,775 individuals. The researchers identified and replicated trans eQTLs for 233 SNPs (reflecting 103 independent loci) previously associated with complex traits at genome-wide significance. Some of these SNPs affect multiple genes in trans that are known to be altered in individuals with disease, such as rs4917014, which is associated with systemic lupus erythematosus (SLE) and alters the expression of $C1QB$ and five type I interferon response genes. DeepSAGE RNA sequencing and chromatin immunoprecipitation and sequencing analysis implicated $IKZF1$ as the causal gene. Variants associated with cholesterol metabolism and type 1 diabetes also showed similar phenomena, indicating that large-scale eQTL mapping provides insights into the downstream effects of many trait-associated variants. The study highlights the importance of trans eQTLs in understanding the pathogenesis of diseases and suggests that future, larger-scale trans eQTL analyses in blood will uncover more regulatory relationships.