title: Towards a phenome-wide catalog of human clinical traits impacted by genetic ancestry.
abstract: BACKGROUND
  Racial/ethnic differences for commonly measured clinical variables are well documented, and it has been postulated that population-specific genetic factors may play a role. The genetic heterogeneity of admixed populations, such as African Americans, provides a unique opportunity to identify genomic regions and variants associated with the clinical variability observed for diseases and traits across populations.
  
  
  METHODS
  To begin a systematic search for these population-specific genomic regions at the phenome-wide scale, we determined the relationship between global genetic ancestry, specifically European and African ancestry, and clinical variables measured in a population of African Americans from BioVU, Vanderbilt University's biorepository linked to de-identified electronic medical records (EMRs) as part of the Epidemiologic Architecture using Genomics and Epidemiology (EAGLE) study. Through billing (ICD-9) codes, procedure codes, labs, and clinical notes, 36 common clinical and laboratory variables were mined from the EMR, including body mass index (BMI), kidney traits, lipid levels, blood pressure, and electrocardiographic measurements. A total of 15,863 DNA samples from non-European Americans were genotyped on the Illumina Metabochip containing ~200,000 variants, of which 11,166 were from African Americans. Tests of association were performed to examine associations between global ancestry and the phenotype of interest.
  
  
  RESULTS
  Increased European ancestry, and conversely decreased African ancestry, was most strongly correlated with an increase in QRS duration, consistent with previous observations that African Americans tend to have shorter a QRS duration compared with European Americans. Despite known racial/ethnic disparities in blood pressure, European and African ancestry was neither associated with diastolic nor systolic blood pressure measurements.
  
  
  CONCLUSIONS
  Collectively, these results suggest that this clinical population can be used to identify traits in which population differences may be due, in part, to population-specific genetics.
authors.affiliation: Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA.
authors.forename: Logan
authors.initials: L
authors.lastname: Dumitrescu
authors.affiliation: Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Restrepo
authors.affiliation: Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Goodloe
authors.affiliation: Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Boston
authors.affiliation: Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Farber-Eger
authors.affiliation: Center for Systems Genomics, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Pendergrass
authors.affiliation: Institute for Computational Biology, Department of Epidemiology and Biostatistics, Case Western Reserve University, Wolstein Research Building, 2103 Cornell Road, Suite 2527, Cleveland, OH 44106 USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Bush
authors.affiliation: Institute for Computational Biology, Department of Epidemiology and Biostatistics, Case Western Reserve University, Wolstein Research Building, 2103 Cornell Road, Suite 2527, Cleveland, OH 44106 USA.
authors.forename: Dana C
authors.initials: DC
authors.lastname: Crawford