title: Conjoint occurrence of GABAB receptor antibodies in Lambert-Eaton myasthenic syndrome with antibodies to the voltage gated calcium channel.
abstract: Antibodies (abs) to the GABAB receptor have been recently found to be responsible for immune-mediated encephalitis with dominant seizures. They are in approximately 50% of cases associated with small-cell lung cancer (SCLC). GABAB receptors are mainly located in the hippocampus, thalamus and cerebellum in the presynaptic and postsynaptic regions of synapses. The main function of these receptors is to reduce activity states of neurons. In some instances, GABAB receptor abs in these patients were accompanied by other antibodies, among them VGCC abs (Lancaster et al., 2010, Boronat et al., 2011). VGCC abs cause paraneoplastic Lambert Eaton myasthenic syndrome (LEMS) by reduction of presynaptic VGCCs (Titulaer et al., 2011). In the domain of CNS disease, VGCC abs have been found in association with paraneoplastic cerebellar ataxia (Mason et al., 1997) and rarely and at low titres also in other paraneoplastic encephalopathies together with Hu abs (Lennon et al., 1995). It has been a long-standing debate if abs in paraneoplastic conditions associate rather with the neurological syndrome or the tumour. Here, we describe the conjoint occurrence of abs to the GABAB receptor and to the VGCC in a patient with SCLC presenting only symptoms of the peripheral nervous system giving another example of the latter hypothesis.
authors.affiliation: Epilepsy Centre Bethel, Krankenhaus Mara, Bielefeld, Germany. Electronic address: muejgan.dogan@mara.de.
authors.forename: Müjgan
authors.initials: M
authors.lastname: Dogan Onugoren
authors.affiliation: Department of Neurology, Sozialmedizinisches Zentrum Ost - Donauspital, Vienna, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Rauschka
authors.affiliation: Epilepsy Centre Bethel, Krankenhaus Mara, Bielefeld, Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Bien
mesh_terms: D000906:Antibodies / Q000378:metabolism*; D015220:Calcium Channels / Q000276:immunology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D015624:Lambert-Eaton Myasthenic Syndrome / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D018482:Muscle, Skeletal / Q000378:metabolism; D049268:Positron-Emission Tomography; D018080:Receptors, GABA-B / Q000276:immunology* / Q000378:metabolism; D015898:Tomography Scanners, X-Ray Computed
chemical_list: D000906:Antibodies; D015220:Calcium Channels; D018080:Receptors, GABA-B; D019788:Fluorodeoxyglucose F18
keywords: GABA(B) receptor antibodies; Lambert–Eaton myasthenic syndrome; Paraneoplastic antibodies; Voltage gated calcium channel antibodies