Identification and functional characterisation of a novel KCNJ2 mutation, Val302del, causing Andersen-Tawil syndrome.

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.

DOI: 10.1139/cjpp-2014-0527

Cite this paper

@article{rdg2015IdentificationAF, title={Identification and functional characterisation of a novel KCNJ2 mutation, Val302del, causing Andersen-Tawil syndrome.}, author={Bal{\'a}zs {\"{O}rd{\"{o}g and Lidia Hategan and Maria B. Kov{\'a}cs and Gy{\"{o}rgy Sepr{\'e}nyi and Zs{\'o}fia Kohajda and Istv{\'a}n Nagy and Zolt{\'a}n Hegedűs and L{\'a}szl{\'o} K{\"{o}rnyei and Norbert Jost and M{\'a}rta Katona and Mikl{\'o}s Szekeres and Tam{\'a}s Forster and Julius Gy Papp and Andr{\'a}s Varr{\'o} and R{\'o}bert Sepp}, journal={Canadian journal of physiology and pharmacology}, year={2015}, volume={93 7}, pages={569-75} }