A Case of Congenital Paramyotonia with Atypical Features in a Family with a New Variation of SCN4A Gene

Fusco Carlo^1*, Elena Pavlidis¹, Carlotta Spagnoli¹, Grazia Gabriella Salerno¹, Daniele Frattini¹ & Pisani Francesco²

¹Child Neurology and Psychiatry Unit, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy
²Child Neurology and Psychiatry Unit, University of Parma, Italy

Fusco Carlo, Child Neurology and Psychiatry Unit, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.

Keywords: SCN4A; Sodium-Channelopathies; Paramyotonia Congenita; EMG

Abstract

SCN4A variations have been identified in various neuromuscular disorders, which are collectively named “sodium channelopathies”.
We report the case of a patient who presented paramyotonia congenita with motor paroxysmal episodes since the neonatal period and some peculiar features. He showed a pathogenic heterozygous variant c.4690G>A (p.V1564) on exon 24 of SCN4A gene inherited by the mother, that showed only mild clinical features.
This case provides other possible clinical features related to the SCN4A gene variations and further highlights the significant clinical heterogeneity of SCN4A-related channelopathies, even in members of the same family with an identical genetic variation.

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