Congenital Myotonia Caused by Mutations in the CIC-1 Chloride Channel Gene

Authors: S. Voháňka 1,2;  J. Bednařík 1,2;  D. Páclová 3;  J. Sedláčková 3;  L. Fajkusová 3
Authors‘ workplace: Neuromuskulární centrum, Neurologická klinika LF MU a FN Brno 1;  CEITEC (Středoevropský technologický institut), MU, Brno 2;  Centrum molekulární biologie a genové terapie FN Brno 3
Published in: Cesk Slov Neurol N 2011; 74/107(4): 467-470
Category: Short Communication


Congenital myotonia is caused by mutations in the CLCN1 chloride channel gene. It can be inherited as either an autosomal dominant (Thomsen’s myotonia) or a recessive (Becker’s myotonia) trait. During 2008–2010, mutations in the chloride channel were found in 7 patients with myotonia, making it the third most frequent cause of myotonia in our records (54 patients with type 2 myotonic dystrophy, 18 with type 1 myotonic dystrophy, and 4 suffering from mutations in the sodium channel). All persons revealed hypertrophic muscles, worsening in cold was found in six cases, and no patients have post-exercise weakness. The semi-dominant mutation p.Arg894X was found most frequently: 5 times among a possible 13 mutations. The recessive mutation p.Pro480HisfsX24 was disclosed three times and p.Phe413Cys twice. All the cases but one are sporadic, thus the majority of patients in our population have Becker´s form of myotonia congenita.

Key words:
myotonia congenita – CLCN1 – channelopathy


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Paediatric neurology Neurosurgery Neurology

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Czech and Slovak Neurology and Neurosurgery

2011 Issue 4

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