Novel CLCN1 Mutation in Carbamazepine-Responsive Myotonia Congenita

• Published in: Pediatric neurology Vol. 42; no. 5; pp. 365 - 368
• Main Authors: Lyons, Michael J., MD, Duron, Reyna, MD, Molinero, Isaac, BA, Sangiuolo, Federica, PhD, Holden, Kenton R., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-05-2010; Elsevier
• Subjects: Adolescent; Biological and medical sciences; Carbamazepine - therapeutic use; Chloride Channels - genetics; Diseases of striated muscles. Neuromuscular diseases; Genes, Recessive; Humans; Male; Medical sciences; Mutation - genetics; Myotonia Congenita - diagnosis; Myotonia Congenita - drug therapy; Myotonia Congenita - genetics; Neurology; Pediatrics; Neuromuscular diseases; Nervous system diseases; Mutation; Myotonia; Carbamazepine
• ISSN: 0887-8994; 1873-5150
• DOI: 10.1016/j.pediatrneurol.2010.01.014

Myotonia congenita is a nondystrophic muscle disorder characterized by muscle stiffness and muscle hypertrophy. The disorder can be inherited in an autosomal-dominant (Thomsen disease) or autosomal-recessive (Becker disease) manner. Both forms of myotonia congenita are attributable to mutations in the CLCN1 gene. Treatment with a variety of medications has led to long-term improvement in the clinical course of affected individuals. We describe a Honduran boy with myotonia congenita and a novel p.L287I mutation in the CLCN1 gene. The patient's unaffected father carries the same mutation, most likely reflecting autosomal-recessive myotonia congenita, with an inability to find a second mutation. The patient received carbamazepine treatment for 1 year, resulting in decreased muscle stiffness, increased strength, and improved quality of life in school and with peers.