title: The association of uncoupling protein 2 (UCP2) exon 8 insertion/deletion polymorphism and ECG derived QRS duration: A cross-sectional study in an Australian rural population.
abstract: BACKGROUND
  Associations between inherited mitochondrial disease and cardiac conduction have been previously described. However, there are no available studies exploring the mitochondrial uncoupling protein 2 gene (UCP2) insertion/deletion (I/D) polymorphisms interaction on cardiac electrical conduction. Our aim was to determine if ECG-derived QRS duration is associated with UCP2 DD genotype in a cross-sectional Australian aging rural population.
  
  
  METHODS
  A retrospective study design utilizing a rural health diabetic screening clinic data-base containing observational data from September 2011 to September 2014. Inclusion criteria included were having ECG parameters such as QRS duration measures and a DNA sample within the same subject. Genomic DNA was extracted and subjects were genotyped for the 45-bp I/D polymorphism in the 3'-untranslated region of UCP2.
  
  
  RESULTS
  281 individuals were available for analysis. On the basis of QRS duration >140ms we found an increased percentage of our population with DD homozygotes, compared to ID heterozygotes and II homozygotes (p=0.047). For other ECG parameters; mean PQ duration, QTc across UCP2 genotypes was not significant (p=NS). QTc using a cut-off >440ms in contingency table analysis revealed no significant differences across UCP2 I/D genotypes. Mean QT dispersion (QTd) was paradoxically less in the UCP2 DD genotype compared to UCP2 II subgroup (p=0.034).
  
  
  CONCLUSIONS
  We have demonstrated an association between increasing ECG-derived QRS duration >140ms and the UCP2 DD polymorphism. The lack of association with ECG derived QTd and UCP2 DD may suggest that gene-related QRS duration prolongation is independent of cardiac hypertrophy.
authors.affiliation: Rural Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia.
authors.forename: Yvonne Yin Leng
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Rural Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Australia School of Health Sciences, Charles Stuart University, Albury, Australia.
authors.forename: Herbert F
authors.initials: HF
authors.lastname: Jelinek
authors.affiliation: Discipline of Pathology, Sydney Medical School, University of Sydney, Australia.
authors.forename: Brett D
authors.initials: BD
authors.lastname: Hambly
authors.affiliation: Rural Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia. Electronic address: reperfusion@hotmail.com.
authors.forename: Craig S
authors.initials: CS
authors.lastname: McLachlan
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D004247:DNA / Q000235:genetics*; D004562:Electrocardiography; D005091:Exons; D005260:Female; D005838:Genotype; D006331:Heart Diseases / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D015994:Incidence; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012189:Retrospective Studies; D012424:Rural Population; D000071246:Uncoupling Protein 2 / Q000235:genetics* / Q000378:metabolism
chemical_list: D000071246:Uncoupling Protein 2; D004247:DNA
keywords: ECG; QRS duration; QTd; Rural population; UCP2 gene