Novel CLCN1 mutation in carbamazepine-responsive myotonia congenita.
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.
Lyons
Michael J
MJ
Greenwood Genetic Center, Greenwood, South Carolina 29418, USA. mlyons@ggc.org
Duron
Reyna
R
Molinero
Isaac
I
Sangiuolo
Federica
F
Holden
Kenton R
KR
D000293:Adolescent; D002220:Carbamazepine / Q000627:therapeutic use*; D018118:Chloride Channels / Q000235:genetics*; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D009224:Myotonia Congenita / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*
C086321:CLC-1 channel; D018118:Chloride Channels; D002220:Carbamazepine