Gene expression levels in humans are highly heritable [1], [2]. Multiple published studies have examined the associations between single nucleotide polymorphism (SNP) variation and microarray gene expression measurements to identify expression Quantitative Trait Loci (eQTLs ), single nucleotide polymorphisms (SNPs) that influence gene expression [3]–[5]. However, most of the published studies have examined gene expression in lymphoblastoid cell lines (LCL) from unphenotyped individuals [3], [4], though a recent paper has described eQTLs in peripheral blood CD4+ lymphocytes of patients with asthma [6]. Integrative genomic analyses can provide functional information regarding significant SNPs found through genomewide association studies (GWAS) or identify the key genes within a locus identified through GWAS. For example, genome-wide expression profiling in LCL from children with asthma [5] was used to localize ORMDL3 (ORM1-like 3 (S. cerevisiae) [MIM 610075]) as the likely gene for childhood asthma in the multi-gene chromosome 17q21 locus found through GWAS [7]. However, this study did not determine whether the eQTLs identified were relevant in primary human tissues in asthma. Integrative genomics studies can also be used to implicate novel genes for complex traits, such as the association between MMP20 (matrix metallopeptidase 20 [MIM 604629]) and age related decline in kidney function [8].
