title: Genome-wide linkage analysis of hemodynamic parameters under mental and physical stress in extended Omani Arab pedigrees: the Oman Family Study.
abstract: BACKGROUND
  We performed a genome-wide scan in a homogeneous Arab population to identify genomic regions linked to blood pressure (BP) and its intermediate phenotypes during mental and physical stress tests.
  
  
  METHODS
  The Oman Family Study subjects (N = 1277) were recruited from five extended families of ~10 generations. Hemodynamic phenotypes were computed from beat-to-beat BP, electrocardiography and impedance cardiography. Multi-point linkage was performed for resting, mental (word conflict test, WCT) and cold pressor (CPT) stress and their reactivity scores (s), using variance components decomposition-based methods implemented in SOLAR.
  
  
  RESULTS
  Genome-wide scans for BP phenotypes identified quantitative trait loci (QTLs) with significant evidence of linkage on chromosomes 1 and 12 for WCT-linked cardiac output (LOD = 3.1) and systolic BP (LOD = 3.5). Evidence for suggestive linkage for WCT was found on chromosomes 3, 17 and 1 for heart rate (LOD = 2.3), DBP (LOD = 2.4) and left ventricular ejection time (LVET), respectively. For △WCT, suggestive QTLs were detected for CO on chr11 (LOD = 2.5), LVET on chr3 (LOD = 2.0) and EDI on chr9 (LOD = 2.1). For CPT, suggestive QTLs for HR and LVET shared the same region on chr22 (LOD 2.3 and 2.8, respectively) and on chr9 (LOD = 2.3) for SBP, chr7 (LOD = 2.4) for SV and chr19 (LOD = 2.6) for CO. For △CPT, CO and TPR top signals were detected on chr15 and 10 (LOD; 2.40, 2.08) respectively.
  
  
  CONCLUSIONS
  Mental stress revealed the largest number of significant and suggestive loci for normal BP reported to date. The study of BP and its intermediate phenotypes under mental and physical stress may help reveal the genes involved in the pathogenesis of essential hypertension.
authors.affiliation: College of Medicine and Health Sciences, Sultan Qaboos University, Sultanate of Oman. mhassan@squ.edu.om
authors.forename: Mohammed O
authors.initials: MO
authors.lastname: Hassan
authors.forename: Deepali
authors.initials: D
authors.lastname: Jaju
authors.forename: V Saroja
authors.initials: VS
authors.lastname: Voruganti
authors.forename: Riad A
authors.initials: RA
authors.lastname: Bayoumi
authors.forename: Sulayma
authors.initials: S
authors.lastname: Albarwani
authors.forename: Saeed
authors.initials: S
authors.lastname: Al-Yahyaee
authors.forename: Afshin
authors.initials: A
authors.lastname: Aslani
authors.forename: Harold
authors.initials: H
authors.lastname: Snieder
authors.forename: Juan C
authors.initials: JC
authors.lastname: Lopez-Alvarenga
authors.forename: Zahir M
authors.initials: ZM
authors.lastname: Al-Anqoudi
authors.forename: Behrooz Z
authors.initials: BZ
authors.lastname: Alizadeh
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Comuzzie
mesh_terms: D000328:Adult; D018912:Arabs / Q000235:genetics; D001794:Blood Pressure / Q000235:genetics; D005190:Family; D005260:Female; D008040:Genetic Linkage; D015894:Genome, Human; D006439:Hemodynamics / Q000235:genetics; D006801:Humans; D008126:Lod Score; D008297:Male; D009850:Oman; D010375:Pedigree; D010641:Phenotype; D040641:Quantitative Trait Loci; D013315:Stress, Psychological / Q000235:genetics; D055815:Young Adult