title: Familial cardiological and targeted genetic evaluation: low yield in sudden unexplained death and high yield in unexplained cardiac arrest syndromes.
abstract: BACKGROUND
  It has been reported that cardiological screening and genetic evaluation in relatives of families with sudden unexplained death syndrome and unexplained cardiac arrest (UCA) may uncover a heritable etiology in a significant proportion of families.
  
  
  OBJECTIVE
  To evaluate the yield of a comprehensive evaluation protocol of a large unselected cohort of consecutive families with autopsy-negative sudden unexplained death syndrome (termed sudden arrhythmic death syndrome [SADS]) and UCA.
  
  
  METHODS
  We studied (1) 109 consecutive families (411 relatives) referred with 1 or more sudden deaths in the family and (2) 52 consecutive probands with UCA (91 relatives) referred by cardiologists between January 2007 and December 2012. A comprehensive cardiological screening was performed followed by targeted genetic evaluation if a clinical phenotype was proven or suspected. Diagnosis was made by a multidisciplinary team using published clinical criteria.
  
  
  RESULTS
  A diagnosis was made in 19 of 109 families with SADS (yield 18%), with the majority having long QT syndrome (LQTS). Diagnosis varied according to proband age, with LQTS most common in the very young (≤20 years) and Brugada syndrome in the older age probands (≥40 years) (P = .03). In contrast, a diagnosis was made in 32 of 52 families with UCA (yield 62%), the majority of which had LQTS and Brugada syndrome. No clinical or circumstantial factors increased the likelihood of diagnosis in families with either SADS or UCA.
  
  
  CONCLUSIONS
  In contrast to previously published series, a comprehensive strategy of cardiological evaluation and targeted genetic testing in more than 100 families with SADS was found to have a lower diagnostic yield (18%). Diagnostic yield in families with UCA was approximately 4 times higher (62%), which is consistent with the published literature.
authors: Department of Cardiology, The Royal Melbourne Hospital, Parkville, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Victoria, Australia.
authors: Saurabh
authors: S
authors: Kumar
authors: Stacey
authors: S
authors: Peters
authors: Tina
authors: T
authors: Thompson
authors: Natalie
authors: N
authors: Morgan
authors: Ivan
authors: I
authors: Maccicoca
authors: Alison
authors: A
authors: Trainer
authors: Dominica
authors: D
authors: Zentner
authors: Jonathan M
authors: JM
authors: Kalman
authors: Ingrid
authors: I
authors: Winship
authors: Jitendra K
authors: JK
authors: Vohra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000235:genetics* / Q000401:mortality; D001344:Autopsy; D053840:Brugada Syndrome / Q000150:complications* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000473:pathology; D004562:Electrocardiography; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006801:Humans; D015994:Incidence; D007223:Infant; D008133:Long QT Syndrome / Q000150:complications* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D012189:Retrospective Studies; D055815:Young Adult
keywords: ARVC; BrS; Brugada syndrome; CPVT; Cardiological screening; ECG; ER; EST; Genetic testing; HCM; LQTS; Long QT syndrome; MRI; SADS; SQT; SUDS; Sudden arrhythmic death syndrome; Sudden unexplained death syndrome; UCA; Unexplained cardiac arrest; arrhythmogenic right ventricular cardiomyopathy; catecholaminergic polymorphic ventricular tachycardia; early repolarization; electrocardiography/electrocardiogram; exercise stress test; hypertrophic cardiomyopathy; long QT syndrome; magnetic resonance imaging; short QT syndrome; sudden arrhythmic death syndrome; sudden unexplained death syndrome; unexplained cardiac arrest