Expanding the spectrum of congenital myopathy linked to recessive mutations in SCN4A

Congenital myopathies are phenotypically and genetically heterogeneous.1 While SCN4A mutations were previously described in hypokalemic or hyperkalemic periodic paralysis, paramyotonia, myotonia congenita, or myasthenic syndrome,2–6 loss-of-function recessive mutations in SCN4A were recently identified in 11 individuals with severe fetal hypokinesia or congenital myopathies.7 Among them, 7 died in the perinatal period and 4 had congenital hypotonia, significant respiratory and swallowing difficulties, and spinal deformities. Acknowledgment: The authors thank the family who participated in this study and the collaborators who contributed to this work: Julie Perrier, Raphaël Schneider, Valérie Biancalana, Vanessa Schartner, Christine Kretz, Antoine Hamel, Anne Dariel, Julie Thompson, Emmanuelle Fleurence, and Jean-Yves Mahé.