Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2014 Jun 17:2014:bcr2014204430.
doi: 10.1136/bcr-2014-204430.

Focal and abnormally persistent paralysis associated with congenital paramyotonia

Armelle Magot  1 , Albert David  2 , Damien Sternberg  3 , Yann Péréon  1
Affiliations
Case Reports

Focal and abnormally persistent paralysis associated with congenital paramyotonia

Armelle Magot et al. BMJ Case Rep. .

Abstract

Mutations of the skeletal muscle voltage-gated sodium channel (NaV1.4) are an established cause of several clinically distinct forms of periodic paralysis and myotonia. Focal paresis has sometimes already been described. We report a case with atypical clinical manifestation comprising paramyotonia and cold-induced persistent and focal paralysis. A 27-year-old woman presented with paramyotonia congenita since her childhood. She experienced during her childhood one brief episode of generalised weakness. At the age of 27, she experienced a focal paresis lasting for several months. The known mutation p.Val1293Ile was found in the muscle sodium channel gene (SCN4A). Channel inactivation is involved in most Na(+) channelopathies. Fast inactivation is known to be responsible for the myotonia phenotype. We hypothesise that the V1293I mutation may also alter the slow inactivation in specific conditions, for example, prolonged cold exposure or prolonged and intensive exercise. This observation broadens the spectrum of clinical manifestations of this sodium channel mutation.

PubMed Disclaimer

Figures

Figure 1
Figure 1
No change in the ulnar CMAP amplitude (<20%) during all provocative repetitive exercises. (A) Repeated short exercises at room temperature. (B) Repeated short exercises at cold. (C) Long exercise during the acute paralysis.
See this image and copyright information in PMC

References

    1. Fournier E, Arzel M, Sternberg D, et al. Electromyography guides toward subgroups of mutations in muscle channelopathies. Ann Neurol 2004;56:650–61 - PubMed
    1. Koch MC, Baumbach K, George AL, et al. Paramyotonia congenita without paralysis on exposure to cold: a novel mutation in the SCN4A gene (Val1293Ile). Neuroreport 1995;6:2001–4 - PubMed
    1. Plassart E, Eymard B, Maurs L, et al. Paramyotonia congenita: genotype to phenotype correlations in two families and report of a new mutation in the sodium channel gene. J Neurol Sci 1996;142:126–33 - PubMed
    1. Burge JA, Hanna MG. Novel insights into the pathomechanisms of skeletal muscle channelopathies. Curr Neurol Neurosci Rep 2012;12:62–9 - PubMed
    1. Yoshinaga H, Sakoda S, Good JM, et al. A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes. J Neurol Sci 2012;315:15–19 - PubMed

Publication types

Substances