title: Clinical and genetic features of Australian families with long QT syndrome: A registry-based study.
abstract: BACKGROUND
  Familial long QT syndrome (LQTS) is a primary arrhythmogenic disorder caused by mutations in ion channel genes. The phenotype ranges from asymptomatic individuals to sudden cardiac arrest and death. LQTS is a rare but significant health problem for which global data should exist. This study sought to provide the first clinical and genetic description of Australian families with LQTS.
  
  
  METHODS
  We performed a cross-sectional study to evaluate clinical and genetic features of families with LQTS. We recruited individuals from the Australian Genetic Heart Disease Registry and Genetic Heart Disease Clinic, in Sydney, Australia, and included those with a diagnosis of LQTS according to the most recent consensus statement.
  
  
  RESULTS
  Among 108 families with LQTS, 173 individuals were affected. Twenty-five (32%) probands had a sudden cardiac death (SCD) event (including appropriate implantable cardioverter defibrillator [ICD] therapy, or resuscitated cardiac arrest). There were 64 (82%) probands who underwent genetic testing, and 34 (53%) had a pathogenic or likely pathogenic mutation in. Having a family history of LQTS was significantly associated with identification of a pathogenic result (79% versus 14%,p<0.0001). There were 16 (9%) participants who experienced delay to diagnosis of at least 12 months.
  
  
  CONCLUSIONS
  This is the first clinical and genetic study in a large cohort of Australian families with LQTS. Findings from this study suggest that the clinical and genetic features in this population are not dissimilar to those described in North American, European, and Asian cohorts. Global-scale information about families with LQTS is an important initiative to ensure diagnostic and management approaches are applicable to different populations and ethnicities.
authors.affiliation: Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia; School of Medicine, University of Sydney, Sydney, Australia.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Burns
authors.affiliation: Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia; School of Medicine, University of Sydney, Sydney, Australia.
authors.forename: Jodie
authors.initials: J
authors.lastname: Ingles
authors.affiliation: Royal Children׳s Hospital, Melbourne, Australia.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Davis
authors.affiliation: Royal Children׳s Hospital, Melbourne, Australia.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Connell
authors.affiliation: Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Belinda
authors.initials: B
authors.lastname: Gray
authors.affiliation: Genetic Health Queensland, Royal Brisbane and Women׳s Hospital, Brisbane, Australia.
authors.forename: Lauren
authors.initials: L
authors.lastname: Hunt
authors.affiliation: Genetic Health Queensland, Royal Brisbane and Women׳s Hospital, Brisbane, Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: McGaughran
authors.affiliation: Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia; School of Medicine, University of Sydney, Sydney, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Semsarian
keywords: Genetic testing; Long QT syndrome; Phenotype; Registry