A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene

Silvia G. Priori, Sandeep V. Pandit, Ilaria Rivolta, Omer Berenfeld, Elena Ronchetti, Amit Dhamoon, Carlo Napolitano, Justus Anumonwo, Marina Raffaele Di Barletta, Smitha Gudapakkam, Giuliano Bosi, Marco Stramba-Badiale, José Jalife

Research output: Contribution to journalArticlepeer-review

Abstract

Short QT syndrome (SQTS) leads to an abbreviated QTc interval and predisposes patients to life-threatening arrhythmias. To date, two forms of the disease have been identified: SQT1, caused by a gain of function substitution in the HERG (IKr) channel, and SQT2, caused by a gain of function substitution in the KvLQT1 (IKs) channel. Here we identify a new variant, "SQT3", which has a unique ECG phenotype characterized by asymmetrical T waves, and a defect in the gene coding for the inwardly rectifying Kir2.1 (IK1) channel. The affected members of a single family had a G514A substitution in the KCNJ2 gene that resulted in a change from aspartic acid to asparagine at position 172 (D172N). Whole-cell patch-clamp studies of the heterologously expressed human D172N channel demonstrated a larger outward IK1 than the wild-type (PK1 greatly accelerated the final phase of repolarization, and shortened the action potential duration. Hence, unlike the known mutations in the two other SQTS forms (N588K in HERG and V307L in KvLQT1), simulations using the D172N and WT/D172N mutations fully accounted for the ECG phenotype of tall and asymmetrically shaped T waves. Although we were unable to test for inducibility of arrhythmia susceptibility due to lack of patients' consent, our computer simulations predict a steeper steady-state restitution curve for the D172N and WT/D172N mutation, compared with WT or to HERG or KvLQT1 mutations, which may predispose SQT3 patients to a greater risk of reentrant arrhythmias.

Original languageEnglish
Pages (from-to)800-807
Number of pages8
JournalCirculation Research
Volume96
Issue number7
DOIs
Publication statusPublished - Apr 15 2005

Keywords

  • Arrhythmias
  • Cellular electrophysiology
  • Genetics
  • Ion channels

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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