title: Recessive CLCN1 mutation presenting as Thomsen disease.
abstract: This case report describes a young man referred for electrodiagnostic evaluation for hand stiffness and intermittent numbness. His needle electromyography revealed diffusely increased insertional and spontaneous motor activity in the form of myotonic discharges. Given the finding of symptomatic myotonia also in his mother, Thomsen myotonia was suspected. Investigations not only confirmed Thomsen myotonia, but also led to the identification of a previously reported heterozygous Becker mutation in both the proband and his mother.
authors.affiliation: Department of Medicine, Physical Medicine & Neurology, Neuromuscular Disease Clinic, Rm 2H22, McMaster University Medical Centre, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada.
authors.forename: Judy
authors.initials: J
authors.lastname: Thomas
authors.affiliation: Fullerton Genetics Laboratory, Mission Hospitals, Asheville, North Carolina, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Tarleton
authors.affiliation: Department of Medicine, Physical Medicine & Neurology, Neuromuscular Disease Clinic, Rm 2H22, McMaster University Medical Centre, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada.
authors.forename: Steven K
authors.initials: SK
authors.lastname: Baker
mesh_terms: D000293:Adolescent; D018118:Chloride Channels / Q000235:genetics*; D004252:DNA Mutational Analysis; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D009224:Myotonia Congenita / Q000235:genetics* / Q000503:physiopathology
chemical_list: C086321:CLC-1 channel; D018118:Chloride Channels