Identification and functional characterisation of a novel KCNJ2 mutation, Val302del, causing andersen–tawil syndrome

Balázs Ördög, Lidia Hategan, Mária Kovács, György Seprényi, Zsófia Kohajda, István Nagy, Zoltán Hegedűs, László Környei, Norbert Jost, Márta Katona, Miklós Szekeres, Tamás Forster, Julius Gy Papp, András Varró, Róbert Sepp

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Loss-of-function mutations of the KCNJ2 gene encoding for the inward rectifier potassium channel subunit Kir2.1 cause Andersen–Tawil Syndrome (ATS), a rare genetic disorder characterised by periodic paralysis, ventricular arrhythmias, and dysmorphic features. Clinical manifestations of the disease appear to vary greatly with the nature of mutation, therefore, functional characterisation of ATS-causing mutations is of clinical importance. In this study, we describe the identification and functional analysis of a novel KCNJ2 mutation, Val302del, identified in a patient with ATS. Heterologously expressed wild type (WT) and Val302del mutant alleles showed similar subcellular distribution of the Kir2.1 protein with high intensity labelling from the membrane region, demonstrating normal membrane trafficking of the Val302del Kir2.1 variant. Cells transfected with the WT allele displayed a robust current with strong inward rectification, while no current above background was detected in cells expressing the Val302del Kir2.1 subunit. Co-transfection of CHO cells with the WT and the Val302del Kir2.1 revealed a dose-dependent inhibitory effect of the Val302del Kir2.1 mutant subunit on WT Kir2.1 currents. These observations indicate that the WT and the Val302del mutant subunits co-assemble in the cell membrane and that the mutation affects potassium conductivity and (or) gating of the WT/Val302del heteromeric Kir2.1 channels.

Original languageEnglish
Pages (from-to)569-575
Number of pages7
JournalCanadian journal of physiology and pharmacology
Volume93
Issue number7
DOIs
Publication statusPublished - Mar 11 2015

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Keywords

  • Andersen–Tawil Syndrome
  • Inward rectifier potassium channel
  • KCNJ2 gene
  • KCNJ2 mutation
  • Kir2.1 subunit

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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