title: Expression quantitative trait loci (eQTL) mapping in Puerto Rican children.
abstract: BACKGROUND
  Expression quantitative trait loci (eQTL) have been identified using tissue or cell samples from diverse human populations, thus enhancing our understanding of regulation of gene expression. However, few studies have attempted to identify eQTL in racially admixed populations such as Hispanics.
  
  
  METHODS
  We performed a systematic eQTL study to identify regulatory variants of gene expression in whole blood from 121 Puerto Rican children with (n = 63) and without (n = 58) asthma. Genome-wide genotyping was conducted using the Illumina Omni2.5M Bead Chip, and gene expression was assessed using the Illumina HT-12 microarray. After completing quality control, we performed a pair-wise genome analysis of ~15 K transcripts and ~1.3 M SNPs for both local and distal effects. This analysis was conducted under a regression framework adjusting for age, gender and principal components derived from both genotypic and mRNA data. We used a false discovery rate (FDR) approach to identify significant eQTL signals, which were next compared to top eQTL signals from existing eQTL databases. We then performed a pathway analysis for our top genes.
  
  
  RESULTS
  We identified 36,720 local pairs in 3,391 unique genes and 1,851 distal pairs in 446 unique genes at FDR <0.05, corresponding to unadjusted P values lower than 1.5x10-4 and 4.5x10-9, respectively. A significant proportion of genes identified in our study overlapped with those identified in previous studies. We also found an enrichment of disease-related genes in our eQTL list.
  
  
  CONCLUSIONS
  We present results from the first eQTL study in Puerto Rican children, who are members of a unique Hispanic cohort disproportionately affected with asthma, prematurity, obesity and other common diseases. Our study confirmed eQTL signals identified in other ethnic groups, while also detecting additional eQTLs unique to our study population. The identified eQTLs will help prioritize findings from future genome-wide association studies in Puerto Ricans.
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: Wei
authors: W
authors: Chen
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: John M
authors: JM
authors: Brehm
authors: Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Jerome
authors: J
authors: Lin
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: Ting
authors: T
authors: Wang
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: Erick
authors: E
authors: Forno
authors: Behavioral Sciences Research Institute, University of Puerto Rico, San Juan, Puerto Rico.
authors: Edna
authors: E
authors: Acosta-Pérez
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: Nadia
authors: N
authors: Boutaoui
authors: Behavioral Sciences Research Institute, University of Puerto Rico, San Juan, Puerto Rico.
authors: Glorisa
authors: G
authors: Canino
authors: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
authors: Juan C
authors: JC
authors: Celedón
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000235:genetics* / Q000473:pathology; D002648:Child; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011647:Puerto Rico; D040641:Quantitative Trait Loci / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D012333:RNA, Messenger