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

SCN4A variations have been identified in various neuromuscular disorders, which are collectively named “sodium channelopathies”. Abstract 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