Pediatric cohort with long QT syndrome – KCNH2 mutation carriers present late onset but severe symptoms –

Junichi Ozawa, Seiko Ohno, Takashi Hisamatsu, Hideki Itoh, Takeru Makiyama, Hiroshi Suzuki, Akihiko Saitoh, Minoru Horie

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


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. Methods and 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: KCNQ1 in 271, KCNH2 in 192, and SCN5A in 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.

Original languageEnglish
Pages (from-to)696-702
Number of pages7
JournalCirculation Journal
Issue number3
Publication statusPublished - Feb 25 2016
Externally publishedYes


  • Child
  • Genetics
  • Long QT syndrome
  • Sex hormone
  • Torsade de pointes

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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