title: Flecainide-Responsive Myotonia Permanens With SNEL Onset: A New Case and Literature Review.
abstract: Sodium channel myotonias are inherited muscle diseases linked to mutations in the voltage-gated sodium channel. These diseases may also affect newborns with variable symptoms. More recently, severe neonatal episodic laryngospasm (SNEL) has been described in a small number of patients. A timely diagnosis of SNEL is crucial because a specific treatment is now available that will likely reduced laryngospasm and improve vital and cerebral outcomes. We report here on an 8-year-old girl who had presented, at birth, with SNEL who subsequently developed myotonia permanens starting at age 3 years. Results of molecular analysis revealed a de novo SCN4A G1306E mutation. The girl was treated with carbamazepine, acetazolamide, and mexiletine, with little improvement; after switching her treatment to flecainide, she experienced a dramatic reduction in muscle stiffness and myotonic symptoms as well as an improvement in behavior.
authors.affiliation: IRCCS Centro Neurolesi "Bonino Pulejo", SS113, via Palermo, c.da Casazza, Messina, Italy; simonaportaro@hotmail.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Portaro
authors.affiliation: Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy;
authors.forename: Carmelo
authors.initials: C
authors.lastname: Rodolico
authors.affiliation: Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy;
authors.forename: Stefano
authors.initials: S
authors.lastname: Sinicropi
authors.affiliation: Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy;
authors.forename: Olimpia
authors.initials: O
authors.lastname: Musumeci
authors.affiliation: Pediatric, Gynecological, Microbiological and Biomedical Sciences, University of Messina, Messina, Italy.
authors.forename: Mariella
authors.initials: M
authors.lastname: Valenzise
authors.affiliation: IRCCS Centro Neurolesi "Bonino Pulejo", SS113, via Palermo, c.da Casazza, Messina, Italy; Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy;
authors.forename: Antonio
authors.initials: A
authors.lastname: Toscano
mesh_terms: D002648:Child; D005260:Female; D005424:Flecainide / Q000627:therapeutic use*; D006801:Humans; D006984:Hypertrophy / Q000209:etiology; D007826:Laryngismus; D018482:Muscle, Skeletal / Q000473:pathology; D009154:Mutation; D009224:Myotonia Congenita / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D062553:NAV1.4 Voltage-Gated Sodium Channel / Q000235:genetics; D061567:Voltage-Gated Sodium Channel Blockers / Q000627:therapeutic use*
chemical_list: D062553:NAV1.4 Voltage-Gated Sodium Channel; C106251:SCN4A protein, human; D061567:Voltage-Gated Sodium Channel Blockers; D005424:Flecainide