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Al Yazidi G, Shevell MI, Srour M. Two Novel KCNQ2 Mutations in 2 Families With Benign Familial Neonatal Convulsions. Child Neurol Open 2017; 4:2329048X17691396. [PMID: 28503627 PMCID: PMC5417349 DOI: 10.1177/2329048x17691396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/10/2016] [Accepted: 11/22/2016] [Indexed: 11/16/2022] Open
Abstract
Benign familial neonatal convulsion is a rare autosomal dominant inherited epilepsy syndrome characterized by unprovoked seizures in the first few days of life, normal psychomotor development, and a positive intergenerational family history of neonatal seizures. Over 90% of the affected individuals have inherited causal mutations in KCNQ2, which encodes for the potassium voltage-gated channel subfamily Q, member 2. Mutations in KCNQ2 are also associated with a severe neonatal encephalopathy phenotype associated with poor seizure control and neurodevelopmental deficits. The authors report the clinical presentations, response to medication, and intrafamilial phenotypic variability in 2 families with benign familial neonatal convulsions, carrying previously unreported heterozygous missense mutations, c.1066C>G (p.Leu356Val) and c.1721G<A (p.Gly574Asp), in KCNQ2. The cases reported herein suggest that inherited missense mutations in KCNQ2 can be associated with an intermediate phenotype and illustrate the challenges associated with prognosis and counselling for individuals with inherited missense mutations in KCNQ2.
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Affiliation(s)
- Ghalia Al Yazidi
- Division of Pediatric Neurology, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montréal, Quebec City, Canada.,Departments of Pediatrics, Neurology and Neurosurgery, McGill University, Montreal, Quebec City, Canada
| | - Michael I Shevell
- Division of Pediatric Neurology, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montréal, Quebec City, Canada.,Departments of Pediatrics, Neurology and Neurosurgery, McGill University, Montreal, Quebec City, Canada
| | - Myriam Srour
- Division of Pediatric Neurology, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montréal, Quebec City, Canada.,Departments of Pediatrics, Neurology and Neurosurgery, McGill University, Montreal, Quebec City, Canada
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Dalen Meurs-van der Schoor C, van Weissenbruch M, van Kempen M, Bugiani M, Aronica E, Ronner H, Vermeulen RJ. Severe Neonatal Epileptic Encephalopathy and KCNQ2 Mutation: Neuropathological Substrate? Front Pediatr 2014; 2:136. [PMID: 25566516 PMCID: PMC4271583 DOI: 10.3389/fped.2014.00136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/17/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neonatal convulsions are clinical manifestations in a heterogeneous group of disorders with different etiology and outcome. They are attributed to several genetic causes. METHODS We describe a patient with intractable neonatal seizures who died from respiratory compromise during a status epilepticus. RESULTS This case report provides electroencephalogram (EEG), MRI, genetic analysis, and neuropathological data. Genetic analysis revealed a de novo heterozygous missense mutation in the KCNQ2 gene, which encodes a subunit of a voltage-gated potassium channel. KCNQ2 gene mutation is associated with intractable neonatal seizures. EEG, MRI, data as well as mutation analysis have been described in other KCNQ2 cases. Post-mortem neuropathological investigation revealed mild malformation of cortical development with increased heterotopic neurons in the deep white matter compared to an age-matched control subject. The new finding of this study is the combination of a KCNQ2 mutation and the cortical abnormalities. CONCLUSION KCNQ2 mutations should be considered in neonates with refractory epilepsy of unknown cause. The mild cortical malformation is an important new finding, though it remains unknown whether these cortical abnormalities are due to the KCNQ2 mutation or are secondary to the refractory seizures.
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Affiliation(s)
| | | | - Marjan van Kempen
- Department of Medical Genetics, University Medical Center , Utrecht , Netherlands
| | - Marianna Bugiani
- Department of Pathology, Neuroscience Campus Amsterdam, VU University Medical Center , Amsterdam , Netherlands ; Department of Child Neurology, Neuroscience Campus Amsterdam, VU University Medical Center , Amsterdam , Netherlands
| | - Eleonora Aronica
- Department of Pathology, Academic Medical Center , Amsterdam , Netherlands
| | - Hanneke Ronner
- Department of Clinical Neurophysiology, VU University Medical Center , Amsterdam , Netherlands
| | - R Jeroen Vermeulen
- Department of Child Neurology, Neuroscience Campus Amsterdam, VU University Medical Center , Amsterdam , Netherlands
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Molecular bases and clinical spectrum of early infantile epileptic encephalopathies. Eur J Med Genet 2012; 55:299-306. [PMID: 22548976 DOI: 10.1016/j.ejmg.2012.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/14/2012] [Indexed: 01/21/2023]
Abstract
Epilepsy can be a challenging diagnosis to make in the neonatal and infantile periods. Seizures in this age group may be due to a serious underlying cause that results in an epileptic encephalopathy. Early infantile epileptic encephalopathy (EIEE) is a progressive neurologic condition that exhibits concomitant cognitive and motor impairment, and is often associated with severe intellectual disability. This condition belongs to the group of age-dependent epileptic encephalopathies, and thus the clinical and electro-encephalographic features change with age as the central nervous system evolves. The molecular bases and the clinical spectrum associated with the early infantile epileptic encephalopathies continue to expand as new genetic discoveries are made. This review will highlight the molecular etiologies of early infantile epileptic encephalopathy, and the clinical and electro-encephalographic changes that take place in these epileptic phenotypes as the brain develops.
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Weckhuysen S, Mandelstam S, Suls A, Audenaert D, Deconinck T, Claes LRF, Deprez L, Smets K, Hristova D, Yordanova I, Jordanova A, Ceulemans B, Jansen A, Hasaerts D, Roelens F, Lagae L, Yendle S, Stanley T, Heron SE, Mulley JC, Berkovic SF, Scheffer IE, de Jonghe P. KCNQ2 encephalopathy: emerging phenotype of a neonatal epileptic encephalopathy. Ann Neurol 2012; 71:15-25. [PMID: 22275249 DOI: 10.1002/ana.22644] [Citation(s) in RCA: 350] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE KCNQ2 and KCNQ3 mutations are known to be responsible for benign familial neonatal seizures (BFNS). A few reports on patients with a KCNQ2 mutation with a more severe outcome exist, but a definite relationship has not been established. In this study we investigated whether KCNQ2/3 mutations are a frequent cause of epileptic encephalopathies with an early onset and whether a recognizable phenotype exists. METHODS We analyzed 80 patients with unexplained neonatal or early-infantile seizures and associated psychomotor retardation for KCNQ2 and KCNQ3 mutations. Clinical and imaging data were reviewed in detail. RESULTS We found 7 different heterozygous KCNQ2 mutations in 8 patients (8/80; 10%); 6 mutations arose de novo. One parent with a milder phenotype was mosaic for the mutation. No KCNQ3 mutations were found. The 8 patients had onset of intractable seizures in the first week of life with a prominent tonic component. Seizures generally resolved by age 3 years but the children had profound, or less frequently severe, intellectual disability with motor impairment. Electroencephalography (EEG) at onset showed a burst-suppression pattern or multifocal epileptiform activity. Early magnetic resonance imaging (MRI) of the brain showed characteristic hyperintensities in the basal ganglia and thalamus that later resolved. INTERPRETATION KCNQ2 mutations are found in a substantial proportion of patients with a neonatal epileptic encephalopathy with a potentially recognizable electroclinical and radiological phenotype. This suggests that KCNQ2 screening should be included in the diagnostic workup of refractory neonatal seizures of unknown origin.
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Affiliation(s)
- Sarah Weckhuysen
- Neurogenetics Group, VIB-Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
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Steinlein OK. Human disorders caused by the disruption of the regulation of excitatory neurotransmission. Results Probl Cell Differ 2008; 44:223-42. [PMID: 17589814 DOI: 10.1007/400_2007_034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The nicotinic acetylcholine receptors (nAChRs) are members of the large family of ligand-gated ion channels, and are constituted by the assembly of five subunits arranged pseudosymmetrically around the central axis that forms a cation-selective ion pore. They are widely distributed in both the nervous system and non-neuronal tissues, and can be activated by endogenous agonists such as acetylcholine or exogenous ligands such as nicotine. Mutations in neuronal nAChRs are found in a rare form of familial nocturnal frontal lobe epilepsy (ADNFLE), while mutations in the neuromuscular subtype of the nAChR are responsible for either congenital myasthenia syndromes (adult subtype of neuromuscular nAChR) or a form of arthrogryposis multiplex congenita type Escobar (fetal subtype of neuromuscular nAChR).
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Affiliation(s)
- Ortrud K Steinlein
- Institute of Human Genetics, Ludwig-Maximilians-University, School of Medicine, Goethestr. 29, 80336 München, Germany.
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Steinlein OK, Conrad C, Weidner B. Benign familial neonatal convulsions: always benign? Epilepsy Res 2006; 73:245-9. [PMID: 17129708 DOI: 10.1016/j.eplepsyres.2006.10.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/20/2006] [Accepted: 10/31/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Benign familial neonatal convulsions (BFNC) is a rare autosomal dominant seizure disorder usually described to be characterized by a benign course, spontaneous remission and normal psychomotor development. The latter statement had come under consideration when a few case reports of families with less than favorable outcomes were published. METHODS Since 1998 a total of 112 families suspected to have BFNC have been referred to our lab for genetic testing. Within this sample we identified private KCNQ2 mutations in 17 BFNC families. For 10 of those 17 families follow up information about the psychomotor development and the outcome were available. RESULTS In 4 (40%) of the 10 families at least 1 affected individual showed delayed psychomotor development or mental retardation. Three of the four mutations were familial, while the fourth mutation was de novo. Mutations associated with an unfavorable outcome tended to be located within the functionally critical S5/S6 regions of the KCNQ2 gene. CONCLUSIONS Our data raise the question if BFNC can indeed be described as a benign disorder, and which are the genetic and/or environmental factors that influence the outcome.
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Affiliation(s)
- O K Steinlein
- Institute of Human Genetics, University Hospital, Ludwig-Maximillians-University, Goethestr. 29, D-80336 Munich, Germany.
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Peña F, Alavez-Pérez N. Epileptiform activity induced by pharmacologic reduction of M-current in the developing hippocampus in vitro. Epilepsia 2006; 47:47-54. [PMID: 16417531 DOI: 10.1111/j.1528-1167.2006.00369.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE Benign familial neonatal convulsions (BFNCs), an inheritable epilepsy that occurs in neonates but not in adults, is caused by hypofunctional mutations in genes codifying for the M-type K+ current. In an attempt to develop an in vitro model of this disease, we tested whether blocking M-current with linopirdine induces epileptiform activity in brain slices from animals of different ages. METHODS Horizontal hippocampus-entorhinal cortex slices were obtained from neonatal (1-2 weeks after birth) and adult (8-9 weeks after birth) rats. Extracellular field recordings of the CA1 region were performed. After recording control conditions, linopirdine was added to the bath, and field activity was recorded continuously for 3 h. 4-Aminopyridine, a drug commonly used to induce epileptiform activity in vitro, was used as a control for our experimental conditions. RESULTS Bath perfusion of linopirdine induced epileptiform activity only in slices from neonatal rats. Epileptiform activity consisted of interictal-like and ictal-like activity. In slices from adult rats, linopirdine induced erratic interictal-like activity. In contrast, 4-aminopyridine was able to induce epileptiform activity in slices from both neonatal and adult rats. CONCLUSIONS We demonstrated that blockade of M-current in vitro produces epileptiform activity with a developmental pattern similar to that observed in BNFCs. This could be an in vitro model that can be used to study the cellular mechanisms of epileptogenesis and the developmental features of BFNCs, as well as to develop some therapeutic strategies.
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Affiliation(s)
- Fernando Peña
- Departamento de Farmacobiología, Cinvestav-Coapa, México City, México.
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Steinlein OK. Genes and mutations in human idiopathic epilepsy. Brain Dev 2004; 26:213-8. [PMID: 15130686 DOI: 10.1016/s0387-7604(03)00149-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2003] [Revised: 07/09/2003] [Accepted: 07/09/2003] [Indexed: 11/20/2022]
Abstract
Thirteen genes have already been identified in human idiopathic epilepsies since 1995, but they account only for a minority of all epilepsy cases. Most of these genes are associated with rare monogenic epilepsy syndromes, but some of them contribute to the common epilepsy subtypes. The questions remains to be answered how many more epilepsy genes exist in brain. Idiopathic epilepsies are common neurological disorders, and it can therefore be expected that the total number of genes associated with an increased seizure susceptibility is much higher than 13. Most of the known genes code for either voltage-gated or ligand gated ion channels, but recently two epilepsy genes have been found which do not fit into the concept of epilepsies as channelopathies. It can therefore be suspected that more than one pathogenetic concept exists in epileptogenesis.
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Affiliation(s)
- Ortrud K Steinlein
- Institute of Human Genetics, University Hospital Bonn, Wilhelmstrasse 31, 53111 Bonn, Germany.
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Tang B, Li H, Xia K, Jiang H, Pan Q, Shen L, Long Z, Zhao G, Cai F. A novel mutation in KCNQ2 gene causes benign familial neonatal convulsions in a Chinese family. J Neurol Sci 2004; 221:31-4. [PMID: 15178210 DOI: 10.1016/j.jns.2004.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 03/04/2004] [Accepted: 03/05/2004] [Indexed: 11/30/2022]
Abstract
Benign familial neonatal convulsions (BFNC) are a rare autosomal dominant inherited epilepsy syndrome. Two voltage-gated potassium channel genes, KCNQ2 on chromosome 20q13.3 and KCNQ3 on chromosome 8q24, have been identified as the genes responsible for benign familial neonatal convulsions. By linkage analysis and mutation analysis of KCNQ2 gene, we found a novel frameshift mutation of KCNQ2 gene, 1931delG, in a large Chinese family with benign familial neonatal convulsions. This mutation is located in the C-terminus of KCNQ2, in codon 644 predicting the replacement of the last 201 amino acids with a stretch of 257 amino acids showing a completely different sequence. An unusual clinical feature of this family is that the seizures of every patient did not remit until 12 to 18 months. This is the first report of KCNQ2 gene mutation in China.
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Affiliation(s)
- Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China.
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Affiliation(s)
- Ortrud K Steinlein
- Institute of Human Genetics, Friedrich-Wilhelms-University Bonn, School of Medicine, Wilhelmstrasse 31, 53111 Bonn, Germany.
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Dedek K, Fusco L, Teloy N, Steinlein OK. Neonatal convulsions and epileptic encephalopathy in an Italian family with a missense mutation in the fifth transmembrane region of KCNQ2. Epilepsy Res 2003; 54:21-7. [PMID: 12742592 DOI: 10.1016/s0920-1211(03)00037-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in the voltage gated K(+)-channel gene KCNQ2 are known to cause benign familial neonatal convulsions (BFNC), which are characterized by a benign course, spontaneous remission and normal psychomotor development. Most KCNQ2 mutations can be predicted to truncate the protein. Only a few amino acid exchanges have been found, and their localization was restricted to either the pore region or the fourth or sixth transmembrane region (TM). We have now identified the first KCNQ2 mutation located within TM5, affecting a highly conserved serine in amino acid position 247 of the predicted protein. The clinical history of the two affected family members is not compatible with typical BFNC. The poor outcome in the index patient raises the question if at least some KCNQ2 mutations might increase the risk to develop therapy-resistant epilepsy. Additional studies are needed to evaluate the possibility of a causal relationship between KCNQ2 mutations and severe early infantile epilepsy.
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Affiliation(s)
- Karin Dedek
- Zentrum für Molekulare Neurobiologie (ZMNH), University Hamburg, Hamburg, Germany
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Abstract
Idiopathic epilepsies, which account for up to 40% of all epilepsies, are mainly caused by genetic factors. Most idiopathic epilepsies are due to oligogenic or multifactorial rather than monogenetic inheritance. Nevertheless, most of what is known today about the molecular genetics of idiopathic epilepsies has been found by analysing large families with rare monogenetic forms of the disease. For the first time, gene defects can be linked to certain epilepsies. Mutations in the CHRNA4 or CHRNB subunits of the neuronal nicotinic acetylcholine receptor lead to familial nocturnal frontal lobe epilepsy, while defects in the voltage-gated potassium channels KCNQ2 and KCNQ3 have recently been found to cause benign familial neonatal convulsions. The voltage-gated sodium channel subunits SCN1B, SCN1A and SCN2A as well as the GABRG2 subunit of the GABA(A) receptor are involved in the pathology of the newly described syndrome generalized epilepsy with febrile seizures plus. These rare monogenetic epilepsies can serve as models for further genetic analysis of the common forms of idiopathic epilepsies.
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Affiliation(s)
- Ortrud K Steinlein
- Institute of Human Genetics, Friedrich-Wilhelms-University of Bonn, Wilhelmstrasse 31, D 53111 Bonn, Germany.
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Steinlein OK. Genes and mutations in idiopathic epilepsy. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 106:139-45. [PMID: 11579434 DOI: 10.1002/ajmg.1571] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Partial or generalized idiopathic epilepsies, which account for up to 40% of all epilepsies, are characterized by a mostly benign course and no apparent etiology other than a genetic predisposition. So far, the genetic defects underlying three different idiopathic epilepsy syndromes have been identified: mutations in the CHRNA4- or CHRNB subunits of the neuronal nicotinic acetylcholine receptor are found in familial nocturnal frontal lobe epilepsy, while defects in the voltage-gated potassium channels KCNQ2 and KCNQ3 have recently been identified in benign familial neonatal convulsions. The syndrome of "generalized epilepsy with febrile seizures plus" can be caused by mutations affecting the voltage-gated sodium channel subunits SCN1B and SCN1A or the gamma 2-subunit of the GABA(A) receptor. The results of recent molecular studies contributed largely to our understanding of the etiology and pathophysiology of idiopathic epilepsies.
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MESH Headings
- Epilepsies, Partial/genetics
- Epilepsies, Partial/metabolism
- Epilepsy/genetics
- Epilepsy/metabolism
- Epilepsy, Benign Neonatal/genetics
- Epilepsy, Benign Neonatal/metabolism
- Epilepsy, Generalized/genetics
- Epilepsy, Generalized/metabolism
- Humans
- Mutation/genetics
- Point Mutation
- Potassium Channels/genetics
- Potassium Channels/metabolism
- Receptors, Cholinergic/genetics
- Receptors, Cholinergic/metabolism
- Receptors, GABA-A/genetics
- Receptors, GABA-A/metabolism
- Seizures, Febrile/genetics
- Seizures, Febrile/metabolism
- Sodium Channels/genetics
- Sodium Channels/metabolism
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Affiliation(s)
- O K Steinlein
- Institute of Human Genetics, University of Bonn, Germany.
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Stefan H, Halász P, Gil-Nagel A, Shorvon S, Bauer G, Ben-Menachem E, Perucca E, Wieser HG, Steinlein O. Recent advances in the diagnosis and treatment of epilepsy. Eur J Neurol 2001; 8:519-39. [PMID: 11784335 DOI: 10.1046/j.1468-1331.2001.00251.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent advances in the diagnosis and treatment of epilepsies are discussed with special consideration of epidemiology and classification, progress in neuroimaging, electrophysiological studies using EEG and MEG, initiation of medical and surgical treatment, the role of new antiepileptic drugs and selected aspects of genetics of idiopathic epilepsies. In addition from conclusions obtained by the review of recent developments suggestions for future work in Europe are discussed. A constructive approach from multicenter studies requires homologous definitions, documentations and standardization of procedures of trials for European multicenter studies.
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Affiliation(s)
- H Stefan
- Neurologische Klinik der Universität Erlangen-Nürnberg (ZEE), Germany.
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Dedek K, Kunath B, Kananura C, Reuner U, Jentsch TJ, Steinlein OK. Myokymia and neonatal epilepsy caused by a mutation in the voltage sensor of the KCNQ2 K+ channel. Proc Natl Acad Sci U S A 2001; 98:12272-7. [PMID: 11572947 PMCID: PMC59804 DOI: 10.1073/pnas.211431298] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
KCNQ2 and KCNQ3 are two homologous K(+) channel subunits that can combine to form heterotetrameric channels with properties of neuronal M channels. Loss-of-function mutations in either subunit can lead to benign familial neonatal convulsions (BFNC), a generalized, idiopathic epilepsy of the newborn. We now describe a syndrome in which BFNC is followed later in life by myokymia, involuntary contractions of skeletal muscles. All affected members of the myokymia/BFNC family carried a mutation (R207W) that neutralized a charged amino acid in the S4 voltage-sensor segment of KCNQ2. This substitution led to a shift of voltage-dependent activation of KCNQ2 and a dramatic slowing of activation upon depolarization. Myokymia is thought to result from hyperexcitability of the lower motoneuron, and indeed both KCNQ2 and KCNQ3 mRNAs were detected in the anterior horn of the spinal cord where the cells of the lower motoneurons arise. We propose that a difference in firing patterns between motoneurons and central neurons, combined with the drastically slowed voltage activation of the R207W mutant, explains why this particular KCNQ2 mutant causes myokymia in addition to BFNC.
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Affiliation(s)
- K Dedek
- Zentrum für Molekulare Neurobiologie, Universität Hamburg, D-20246 Hamburg, Germany
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Maihara T, Tsuji M, Higuchi Y, Hattori H. Benign familial neonatal convulsions followed by benign epilepsy with centrotemporal spikes in two siblings. Epilepsia 1999; 40:110-3. [PMID: 9924911 DOI: 10.1111/j.1528-1157.1999.tb01997.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To report on sibling cases with benign familial neonatal convulsions (BFNC) followed by benign epilepsy with centrotemporal spikes (BECT). METHODS Case histories and EEGs were obtained for the two siblings with neonatal and subsequent epileptic seizures in one pedigree with BFNC. RESULTS The family included six affected cases of BFNC in two generations: the proband, the proband's mother and two sisters, and the proband's maternal uncle and his daughter. The proband developed a generalized tonic convulsion 2 days after birth with no apparent cause and normal interictal EEG, and experienced a total of 18 episodes of tonic or clonic seizures or both by age 9 months. In the follow-up course, an EEG recording showed rolandic discharges at 2 years, and a sylvian seizure occurred at 4 years during sleep. On carbamazepine therapy, the last seizure was recorded at 9 years after a total of 11 episodes of sylvian seizures, with normal EEGs after 12 years. The proband's sister experienced nine episodes of brief tonic seizures between 7 and 9 days after birth, and also developed eight episodes of sylvian seizures from 4 to 7 years, with rolandic discharges on EEG until age 9 years. All of the family members had normal psychomotor development, with no neurologic sequelae. CONCLUSIONS This report of BFNC followed by BECT in sibling cases is significant in view of the genetic analysis and the classification of epilepsies and epileptic syndromes.
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Affiliation(s)
- T Maihara
- Department of Pediatrics, Japanese Red Cross Society Wakayama Medical Center
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Abstract
The current International Classification of Epilepsies and Epileptic Syndromes has classified a number of age-related epileptic syndromes in children, but some of these entities have not been well delineated and many syndromes not included in the International Classification have been proposed. This article is intended to supplement some of the currently listed childhood epileptic syndromes, discuss certain problems with the classification system, and review some of the proposed pediatric syndromes.
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Affiliation(s)
- K Watanabe
- Department of Pediatrics, Nagoya University School of Medicine, Japan.
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