title: Cascade screening in families with inherited cardiac diseases driven by cardiologists: feasibility and nationwide outcome in long QT syndrome.
abstract: OBJECTIVE
  We assessed the outcome of cascade screening of families with congenital long QT syndrome (LQTS) in Danish heart centers.
  
  
  METHODS
  Affected family members were identified through systematic family screening.
  
  
  RESULTS
  In total, 228 affected relatives were identified from 90 families. A disease-causing mutation useful for presymptomatic genetic testing was found in 82% of probands. Two-thirds of affected relatives fulfilled electrocardiographic criteria for the diagnosis, whereas diagnosis was based on genetic findings in only one-third. The majority of affected relatives were asymptomatic. Symptomatic relatives and probands most often presented with syncope, followed by aborted cardiac arrest and sudden cardiac death. A serious cardiac event (SCE, such as syncope, aborted cardiac arrest or cardiac arrest) was reported by 32% of affected relatives and 87% of probands (p < 0.0001). Fifty-two percent of affected relatives were on β-blockers and 11% had an implantable cardioverter defibrillator (ICD), as compared to 88 and 49% of probands (p < 0.0001). Appropriate ICD therapy was given to 13% of affected relatives and to 27% of probands (p = 0.1).
  
  
  CONCLUSIONS
  Clinically driven cascade screening of Danish LQTS families identified 2-3 affected relatives per proband. Affected relatives had milder disease courses, but SCEs in a subset strongly support screening. Danish cardiologists have adopted cascade screening of LQTS families according to specific Danish guidelines.
authors: Department of Cardiology, The Heart Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
authors: Juliane
authors: J
authors: Theilade
authors: Jørgen
authors: J
authors: Kanters
authors: Finn Lund
authors: FL
authors: Henriksen
authors: Michael
authors: M
authors: Gilså-Hansen
authors: Jesper Hastrup
authors: JH
authors: Svendsen
authors: Ole
authors: O
authors: Eschen
authors: Egon
authors: E
authors: Toft
authors: Jesper Irving
authors: JI
authors: Reimers
authors: Anne
authors: A
authors: Tybjærg-Hansen
authors: Michael
authors: M
authors: Christiansen
authors: Henrik Kjærulf
authors: HK
authors: Jensen
authors: Henning
authors: H
authors: Bundgaard
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000072237:ERG1 Potassium Channel; D042241:Early Diagnosis; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D005240:Feasibility Studies; D005260:Female; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D007223:Infant; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000188:drug therapy* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D055815:Young Adult
chemical_list: D000319:Adrenergic beta-Antagonists; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C489622:KCNE1 protein, human; C489619:KCNE2 protein, human; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D062554:NAV1.5 Voltage-Gated Sodium Channel; D024642:Potassium Channels, Voltage-Gated; C568320:SCN5A protein, human