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Guidelines on clinical presentation and management of nondystrophic myotonias.

Authors :
Stunnenberg BC
LoRusso S
Arnold WD
Barohn RJ
Cannon SC
Fontaine B
Griggs RC
Hanna MG
Matthews E
Meola G
Sansone VA
Trivedi JR
van Engelen BGM
Vicart S
Statland JM
Source :
Muscle & nerve [Muscle Nerve] 2020 Oct; Vol. 62 (4), pp. 430-444. Date of Electronic Publication: 2020 May 27.
Publication Year :
2020

Abstract

The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.<br /> (© 2020 Wiley Periodicals, Inc.)

Details

Language :
English
ISSN :
1097-4598
Volume :
62
Issue :
4
Database :
MEDLINE
Journal :
Muscle & nerve
Publication Type :
Academic Journal
Accession number :
32270509
Full Text :
https://doi.org/10.1002/mus.26887