A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes

Harumi Yoshinaga, Shunichi Sakoda, Jean Marc Good, Masanori P. Takahashi, Tomoya Kubota, Eri Arikawa-Hirasawa, Tomohiko Nakata, Kinji Ohno, Tetsuro Kitamura, Katsuhiro Kobayashi, Yoko Ohtsuka

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Mutations in the pore-forming subunit of the skeletal muscle sodium channel (SCN4A) are responsible for hyperkalemic periodic paralysis, paramyotonia congenita and sodium channel myotonia. These disorders are classified based on their cardinal symptoms, myotonia and/or paralysis. We report the case of a Japanese boy with a novel mutation of SCN4A, p.I693L, who exhibited severe episodic myotonia from infancy and later onset mild paralytic attack. He started to have apneic episodes with generalized hypertonia at age of 11 months, then developed severe episodic myotonia since 2 years of age. He presented characteristic generalized features which resembled Schwarz-Jampel syndrome. After 7 years old, paralytic episodes occurred several times a year. The compound muscle action potential did not change during short and long exercise tests. Functional analysis of the mutant channel expressed in cultured cell revealed enhancement of the activation and disruption of the slow inactivation, which were consistent with myotonia and paralytic attack. The severe clinical features in his infancy may correspond to myotonia permanence, however, he subsequently experienced paralytic attacks. This case provides an example of the complexity and overlap of the clinical features of sodium channel myotonic disorders.

Original languageEnglish
Pages (from-to)15-19
Number of pages5
JournalJournal of the Neurological Sciences
Volume315
Issue number1-2
DOIs
Publication statusPublished - Apr 15 2012

Fingerprint

Myotonia
Age of Onset
Myotonic Disorders
Mutation
Sodium Channels
Hyperkalemic Periodic Paralysis
Exercise Test
Paralysis
Action Potentials
Cultured Cells
Skeletal Muscle
Muscles

Keywords

  • Activation
  • Channelopathy
  • Na channel
  • Schwarz-Jampel syndrome
  • SCN4A
  • Skeletal muscle
  • Slow inactivation

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

Cite this

Yoshinaga, H., Sakoda, S., Good, J. M., Takahashi, M. P., Kubota, T., Arikawa-Hirasawa, E., ... Ohtsuka, Y. (2012). A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes. Journal of the Neurological Sciences, 315(1-2), 15-19. https://doi.org/10.1016/j.jns.2011.12.015

A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes. / Yoshinaga, Harumi; Sakoda, Shunichi; Good, Jean Marc; Takahashi, Masanori P.; Kubota, Tomoya; Arikawa-Hirasawa, Eri; Nakata, Tomohiko; Ohno, Kinji; Kitamura, Tetsuro; Kobayashi, Katsuhiro; Ohtsuka, Yoko.

In: Journal of the Neurological Sciences, Vol. 315, No. 1-2, 15.04.2012, p. 15-19.

Research output: Contribution to journalArticle

Yoshinaga, H, Sakoda, S, Good, JM, Takahashi, MP, Kubota, T, Arikawa-Hirasawa, E, Nakata, T, Ohno, K, Kitamura, T, Kobayashi, K & Ohtsuka, Y 2012, 'A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes', Journal of the Neurological Sciences, vol. 315, no. 1-2, pp. 15-19. https://doi.org/10.1016/j.jns.2011.12.015
Yoshinaga H, Sakoda S, Good JM, Takahashi MP, Kubota T, Arikawa-Hirasawa E et al. A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes. Journal of the Neurological Sciences. 2012 Apr 15;315(1-2):15-19. https://doi.org/10.1016/j.jns.2011.12.015
Yoshinaga, Harumi ; Sakoda, Shunichi ; Good, Jean Marc ; Takahashi, Masanori P. ; Kubota, Tomoya ; Arikawa-Hirasawa, Eri ; Nakata, Tomohiko ; Ohno, Kinji ; Kitamura, Tetsuro ; Kobayashi, Katsuhiro ; Ohtsuka, Yoko. / A novel mutation in SCN4A causes severe myotonia and school-age-onset paralytic episodes. In: Journal of the Neurological Sciences. 2012 ; Vol. 315, No. 1-2. pp. 15-19.
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