title: Limbic encephalitis with anti-GAD antibodies and Thomsen myotonia: a casual or causal association?
abstract: The association between hereditary myotonic disorders and epilepsy is seldom described in the literature. To date, few reports have dealt with dystrophic myotonias, whereas a single case demonstrating an association between sporadic congenital myotonia and epilepsy was recently reported in a patient carrying a de novo mutation of the CLCN1 gene. Additional evidence for a role of CLCN1 in the pathogenesis of epilepsy is derived from large-scale exome analysis of ion channel variants and expression studies. Here, we describe the first case of association between familial Thomsen myotonia and epilepsy. All the affected members of a two-generation family presented myotonia and disclosed a pathogenic mutation in CLCN1. In addition, one individual experienced epileptic seizures due to limbic encephalitis (LE) with anti-GAD antibodies. The occurrence of the two diseases in this patient could be a chance association, however, CLCN1 mutation, as a susceptibility factor for epilepsy through dysfunction of GABAA inhibitory signalling, cannot be ruled out as a possible influence.
authors.affiliation: IRCCS Istituto delle Scienze Neurologiche di Bologna, Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Licchetta
authors.affiliation: IRCCS Istituto delle Scienze Neurologiche di Bologna, Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bisulli
authors.affiliation: IRCCS Istituto delle Scienze Neurologiche di Bologna, Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Naldi
authors.affiliation: IRCCS Istituto delle Scienze Neurologiche di Bologna, Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
authors.forename: Greta
authors.initials: G
authors.lastname: Mainieri
authors.affiliation: IRCCS Istituto delle Scienze Neurologiche di Bologna, Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Tinuper
mesh_terms: D000293:Adolescent; D018118:Chloride Channels / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000276:immunology*; D006801:Humans; D020363:Limbic Encephalitis / Q000150:complications / Q000235:genetics / Q000276:immunology*; D008297:Male; D009154:Mutation; D009224:Myotonia Congenita / Q000150:complications / Q000235:genetics / Q000276:immunology*; D010375:Pedigree
chemical_list: C086321:CLC-1 channel; D018118:Chloride Channels; D005968:Glutamate Decarboxylase
keywords: Thomsen myotonia; chloride channels; limbic encephalitis; seizures