Referenced in: none

Automatically associated channels: Cav2.2

Title: CACNA1B mutation is linked to unique myoclonus-dystonia syndrome.

Authors: Justus L Groen, Arturo Andrade, Katja Ritz, Hamid Jalalzadeh, Martin Haagmans, Ted E J Bradley, Aldo Jongejan, Dineke S Verbeek, Peter Nürnberg, Sylvia Denome, Raoul C M Hennekam, Diane Lipscombe, Frank Baas, Marina A J Tijssen

Journal, date & volume: Hum. Mol. Genet., 2015 Feb 15 , 24, 987-93

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/25296916

Abstract
Using exome sequencing and linkage analysis in a three-generation family with a unique dominant myoclonus-dystonia-like syndrome with cardiac arrhythmias, we identified a mutation in the CACNA1B gene, coding for neuronal voltage-gated calcium channels CaV2.2. This mutation (c.4166G>A;p.Arg1389His) is a disruptive missense mutation in the outer region of the ion pore. The functional consequences of the identified mutation were studied using whole-cell and single-channel patch recordings. High-resolution analyses at the single-channel level showed that, when open, R1389H CaV2.2 channels carried less current compared with WT channels. Other biophysical channel properties were unaltered in R1389H channels including ion selectivity, voltage-dependent activation or voltage-dependent inactivation. CaV2.2 channels regulate transmitter release at inhibitory and excitatory synapses. Functional changes could be consistent with a gain-of-function causing the observed hyperexcitability characteristic of this unique myoclonus-dystonia-like syndrome associated with cardiac arrhythmias.