title: An in vivo cardiac assay to determine the functional consequences of putative long QT syndrome mutations.
abstract: BACKGROUND
  Genetic testing for Long QT Syndrome is now a standard and integral component of clinical cardiology. A major obstacle to the interpretation of genetic findings is the lack of robust functional assays to determine the pathogenicity of identified gene variants in a high-throughput manner.
  
  
  OBJECTIVE
  The goal of this study was to design and test a high-throughput in vivo cardiac assay to distinguish between disease-causing and benign KCNH2 (hERG1) variants, using the zebrafish as a model organism.
  
  
  RESULTS
  We tested the ability of previously characterized Long QT Syndrome hERG1 mutations and polymorphisms to restore normal repolarization in the kcnh2-knockdown embryonic zebrafish. The cardiac assay correctly identified a benign variant in 9 of 10 cases (negative predictive value 90%), whereas correctly identifying a disease-causing variant in 39/39 cases (positive predictive value 100%).
  
  
  CONCLUSIONS
  The in vivo zebrafish cardiac assay approaches the accuracy of the current benchmark in vitro assay for the detection of disease-causing mutations, and is far superior in terms of throughput rate. Together with emerging algorithms for interpreting a positive long QT syndrome genetic test, the zebrafish cardiac assay provides an additional tool for the final determination of pathogenicity of gene variants identified in long QT syndrome genetic screening.
authors.affiliation: Division of Pediatric Cardiology, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, 100 N. Mario Capecchi Drive, Salt Lake City, UT 84113, USA.
authors.forename: Chuanchau J
authors.initials: CJ
authors.lastname: Jou
authors.forename: Spencer M
authors.initials: SM
authors.lastname: Barnett
authors.forename: Jian-Tao
authors.initials: JT
authors.lastname: Bian
authors.forename: H Cindy
authors.initials: HC
authors.lastname: Weng
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Sheng
authors.forename: Martin
authors.initials: M
authors.lastname: Tristani-Firouzi
mesh_terms: D000465:Algorithms; D000818:Animals; D004195:Disease Models, Animal; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D055785:Gene Knockdown Techniques; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005820:Genetic Testing; D006321:Heart / Q000503:physiopathology*; D057166:High-Throughput Screening Assays / Q000379:methods*; D008133:Long QT Syndrome / Q000235:genetics* / Q000503:physiopathology*; D009154:Mutation / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D011237:Predictive Value of Tests; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics
chemical_list: C527141:Erg protein, zebrafish; D051638:Ether-A-Go-Go Potassium Channels; D029961:Zebrafish Proteins