Luo, S;
Sampedro Castañeda, M;
Matthews, E;
Sud, R;
Hanna, MG;
Sun, J;
Song, J;
... Männikkö, R; + view all
(2018)
Hypokalaemic periodic paralysis and myotonia in a patient with homozygous mutation p.R1451L in NaV1.4.
Scientific Reports
, 8
(1)
, Article 9714. 10.1038/s41598-018-27822-2.
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Abstract
Dominantly inherited channelopathies of the skeletal muscle voltage-gated sodium channel NaV1.4 include hypokalaemic and hyperkalaemic periodic paralysis (hypoPP and hyperPP) and myotonia. HyperPP and myotonia are caused by NaV1.4 channel overactivity and overlap clinically. Instead, hypoPP is caused by gating pore currents through the voltage sensing domains (VSDs) of NaV1.4 and seldom co-exists clinically with myotonia. Recessive loss-of-function NaV1.4 mutations have been described in congenital myopathy and myasthenic syndromes. We report two families with the NaV1.4 mutation p.R1451L, located in VSD-IV. Heterozygous carriers in both families manifest with myotonia and/or hyperPP. In contrast, a homozygous case presents with both hypoPP and myotonia, but unlike carriers of recessive NaV1.4 mutations does not manifest symptoms of myopathy or myasthenia. Functional analysis revealed reduced current density and enhanced closed state inactivation of the mutant channel, but no evidence for gating pore currents. The rate of recovery from inactivation was hastened, explaining the myotonia in p.R1451L carriers and the absence of myasthenic presentations in the homozygous proband. Our data suggest that recessive loss-of-function NaV1.4 variants can present with hypoPP without congenital myopathy or myasthenia and that myotonia can present even in carriers of homozygous NaV1.4 loss-of-function mutations.
| Type: | Article |
|---|---|
| Title: | Hypokalaemic periodic paralysis and myotonia in a patient with homozygous mutation p.R1451L in NaV1.4 |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41598-018-27822-2 |
| Publisher version: | https://doi.org/10.1038/s41598-018-27822-2 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Department of Neuromuscular Diseases |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10051982 |
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