title: Pediatric Cohort With Long QT Syndrome　- KCNH2 Mutation Carriers Present Late Onset But Severe Symptoms.
abstract: BACKGROUND
  In children with long QT syndrome (LQTS), risk factors for cardiac events have been reported, but age-, gender- and genotype-related differences in prognosis remain unknown in Asian countries.
  
  
  RESULTS
  The study examined clinical prognosis at age between 1 and 20 years in 496 LQTS patients who were genotyped as either of LQT1-3 (male, n=206). Heterozygous mutations were observed in 3 major responsible genes:KCNQ1in271,KCNH2in 192, andSCN5Ain 33 patients. LQTS-associated events were classified into 3 categories: (1) syncope (n=133); (2) repetitive torsade de pointes (TdP, n=3); and (3) cardiopulmonary arrest (CPA, n=4). The risk of cardiac events was significantly lower in LQT1 girls than boys≤12 years (HR, 0.55), whereas LQT2 female patients ≥13 years had the higher risk of cardiac events than male patients (HR, 4.60). Patients in the repetitive TdP or CPA group included 1 LQT1 female patient, 1 LQT2 male patient, and 5 LQT2 female patients. All LQT2 patients in these groups had TdP repeatedly immediately after the antecedent event. In addition, all 5 female LQT2 patients in these groups had the event after or near puberty.
  
  
  CONCLUSIONS
  Female LQT2 children might have repeated TdP shortly after prior events, especially after puberty. (Circ J 2016; 80: 696-702).
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ozawa
authors.forename: Seiko
authors.initials: S
authors.lastname: Ohno
authors.forename: Takashi
authors.initials: T
authors.lastname: Hisamatsu
authors.forename: Hideki
authors.initials: H
authors.lastname: Itoh
authors.forename: Takeru
authors.initials: T
authors.lastname: Makiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Saitoh
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000209:etiology / Q000235:genetics; D006801:Humans; D007223:Infant; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D008133:Long QT Syndrome / Q000150:complications / Q000175:diagnosis / Q000235:genetics; D008297:Male; D009154:Mutation; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics; D011379:Prognosis; D013575:Syncope / Q000175:diagnosis / Q000209:etiology / Q000235:genetics; D016171:Torsades de Pointes / Q000175:diagnosis / Q000209:etiology / Q000235:genetics
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human