Mapping of hepatic expression quantitative trait loci (eQTLs) in a Han Chinese population

J Med Genet. 2014 May;51(5):319-26. doi: 10.1136/jmedgenet-2013-102045. Epub 2014 Mar 24.

Abstract

Background: Elucidating the genetic basis underlying hepatic gene expression variability is of importance to understand the aetiology of the disease and variation in drug metabolism. To date, no genome-wide expression quantitative trait loci (eQTLs) analysis has been conducted in the Han Chinese population, the largest ethnic group in the world.

Methods: We performed a genome-wide eQTL mapping in a set of Han Chinese liver tissue samples (n=64). The data were then compared with published eQTL data from a Caucasian population. We then performed correlations between these eQTLs with important pharmacogenes, and genome-wide association study (GWAS) identified single nucleotide polymorphisms (SNPs), in particular those identified in the Asian population.

Results: Our analyses identified 1669 significant eQTLs (false discovery rate (FDR) < 0.05). We found that 41% of Asian eQTLs were also eQTLs in Caucasians at the genome-wide significance level (p=10⁻⁸). Both cis- and trans-eQTLs in the Asian population were also more likely to be eQTLs in Caucasians (p<10⁻⁴). Enrichment analyses revealed that trait-associated GWAS-SNPs were enriched within the eQTLs identified in our data, so were the GWAS-SNPs specifically identified in Asian populations in a separate analysis (p<0.001 for both). We also found that hepatic expression of very important pharmacogenetic (VIP) genes (n=44) and a manually curated list of major genes involved in pharmacokinetics (n=341) were both more likely to be controlled by eQTLs (p<0.002 for both).

Conclusions: Our study provided, for the first time, a comprehensive hepatic eQTL analysis in a non-European population, further generating valuable data for characterising the genetic basis of human diseases and pharmacogenetic traits.

Keywords: Clinical genetics; Genetics; Genome-wide; Molecular genetics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Asian People / genetics*
  • Gene Expression Profiling
  • Genetics, Population
  • Genome-Wide Association Study
  • Humans
  • Liver / physiology*
  • Male
  • Pharmacogenetics
  • Polymorphism, Single Nucleotide
  • Quantitative Trait Loci*
  • White People / genetics