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Li J, Mei S, Mao X, Wan L, Wang H, Xiao B, Song Y, Gu W, Liu Y, Long L. De novo variants in KCNJ3 are associated with early-onset epilepsy. J Med Genet 2024; 61:319-324. [PMID: 37963718 DOI: 10.1136/jmg-2023-109201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 10/14/2023] [Indexed: 11/16/2023]
Abstract
BACKGROUND KCNJ3 encodes a subunit of G-protein-coupled inwardly rectifying potassium channels, which are important for cellular excitability and inhibitory neurotransmission. However, the genetic basis of KCNJ3 in epilepsy has not been determined. This study aimed to identify the pathogenic KCNJ3 variants in patients with epilepsy. METHODS Trio exome sequencing was performed to determine potential variants of epilepsy. Individuals with KCNJ3 variants were recruited for this study. Detailed clinical information and genetic data were obtained and systematically reviewed. Whole-cell patch-clamp recordings were performed to evaluate the functional consequences of the identified variants. RESULTS Two de novo missense variants (c.998T>C (p.Leu333Ser) and c.938G>A (p. Arg313Gln)) in KCNJ3 were identified in two unrelated families with epilepsy. The variants were absent from the gnomAD database and were assumed to be damaging or probably damaging using multiple bioinformatics tools. They were both located in the C-terminal domain. The amino acid residues were highly conserved among various species. Clinically, the seizures occurred at a young age and were under control after combined treatment. Electrophysiological analysis revealed that the KCNJ3 Leu333Ser and Arg313Gln variants significantly compromised the current activities and exhibited loss-of-function (LOF) effects. CONCLUSION Our findings suggest that de novo LOF variants in KCNJ3 are associated with early-onset epilepsy. Genetic testing of KCNJ3 in patients with epilepsy may serve as a strategy for precision medicine.
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Affiliation(s)
- Juan Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, China
| | - Shiyue Mei
- Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan, China
| | - Xiao Mao
- Department of Medical Genetics, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
- National Health Commission Key Laboratory for Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Lily Wan
- Department of Anatomy & Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
| | - Hua Wang
- Department of Medical Genetics, Hunan Children's Hospital, Changsha, Hunan, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, China
| | - Yanmin Song
- Department of Emergency Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Weiyue Gu
- Chigene (Beijing) Translational Medical Research Center Co. Ltd, Beijing, China
| | - Yan Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, China
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Taylor EL, Weaver SR, Lorang IM, Arnold KM, Bradley EW, Marron Fernandez de Velasco E, Wickman K, Westendorf JJ. GIRK3 deletion facilitates kappa opioid signaling in chondrocytes, delays vascularization and promotes bone lengthening in mice. Bone 2022; 159:116391. [PMID: 35314385 PMCID: PMC9035100 DOI: 10.1016/j.bone.2022.116391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/03/2022] [Accepted: 03/14/2022] [Indexed: 11/29/2022]
Abstract
Long bones are formed and repaired through the process of endochondral ossification. Activation of G protein-coupled receptor (GPCR) signaling pathways is crucial for skeletal development and long bone growth. G protein-gated inwardly-rectifying K+ (GIRK) channel genes are key functional components and effectors of GPCR signaling pathways in excitable cells of the heart and brain, but their roles in non-excitable cells that directly contribute to endochondral bone formation have not been studied. In this study, we analyzed skeletal phenotypes of Girk2-/-, Girk3-/- and Girk2/3-/- mice. Bones from 12-week-old Girk2-/- mice were normal in length, but femurs and tibiae from Girk3-/- and Girk2/3-/- mice were longer than age-matched controls at 12-weeks-old. Epiphyseal chondrocytes from 5-day-old Girk3-/- mice expressed higher levels of genes involved in collagen chain trimerization and collagen fibril assembly, lower levels of genes encoding VEGF receptors, and produced larger micromasses than wildtype chondrocytes in vitro. Girk3-/- chondrocytes were also more responsive to the kappa opioid receptor (KOR) ligand dynorphin, as evidenced by greater pCREB expression, greater cAMP and GAG production, and upregulation of Col2a1 and Sox9 transcripts. Imaging studies showed that Kdr (Vegfr2) and endomucin expression was dramatically reduced in bones from young Girk3-/- mice, supporting a role for delayed vasculogenesis and extended postnatal endochondral bone growth. Together these data indicate that GIRK3 controls several processes involved in bone lengthening.
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Affiliation(s)
- Earnest L Taylor
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, United States of America; Department of Cell Biology, University of North Carolina, NC, United States of America
| | - Samantha R Weaver
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, United States of America
| | - Ian M Lorang
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, United States of America; University of Washington School of Medicine, Seattle, WA, United States of America
| | - Katherine M Arnold
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States of America
| | - Elizabeth W Bradley
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, United States of America; Department of Orthopedic Surgery, University of Minnesota, Minneapolis, MN, United States of America
| | | | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States of America
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, United States of America; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States of America.
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3
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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4
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Kamarajan C, Pandey AK, Chorlian DB, Manz N, Stimus AT, Edenberg HJ, Wetherill L, Schuckit M, Wang JC, Kuperman S, Kramer J, Tischfield JA, Porjesz B. A KCNJ6 gene polymorphism modulates theta oscillations during reward processing. Int J Psychophysiol 2017; 115:13-23. [PMID: 27993610 PMCID: PMC5392377 DOI: 10.1016/j.ijpsycho.2016.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/09/2016] [Accepted: 12/15/2016] [Indexed: 12/16/2022]
Abstract
Event related oscillations (EROs) are heritable measures of neurocognitive function that have served as useful phenotype in genetic research. A recent family genome-wide association study (GWAS) by the Collaborative Study on the Genetics of Alcoholism (COGA) found that theta EROs during visual target detection were associated at genome-wide levels with several single nucleotide polymorphisms (SNPs), including a synonymous SNP, rs702859, in the KCNJ6 gene that encodes GIRK2, a G-protein inward rectifying potassium channel that regulates excitability of neuronal networks. The present study examined the effect of the KCNJ6 SNP (rs702859), previously associated with theta ERO to targets in a visual oddball task, on theta EROs during reward processing in a monetary gambling task. The participants were 1601 adolescent and young adult offspring within the age-range of 17-25years (800 males and 801 females) from high-dense alcoholism families as well as control families of the COGA prospective study. Theta ERO power (3.5-7.5Hz, 200-500ms post-stimulus) was compared across genotype groups. ERO theta power at central and parietal regions increased as a function of the minor allele (A) dose in the genotype (AA>AG>GG) in both loss and gain conditions. These findings indicate that variations in the KCNJ6 SNP influence magnitude of theta oscillations at posterior loci during the evaluation of loss and gain, reflecting a genetic influence on neuronal circuits involved in reward-processing. Increased theta power as a function of minor allele dose suggests more efficient cognitive processing in those carrying the minor allele of the KCNJ6 SNPs. Future studies are needed to determine the implications of these genetic effects on posterior theta EROs as possible "protective" factors, or as indices of delays in brain maturation (i.e., lack of frontalization).
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Affiliation(s)
- Chella Kamarajan
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Ashwini K Pandey
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - David B Chorlian
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Niklas Manz
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Arthur T Stimus
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | | | - Leah Wetherill
- Indiana University School of Medicine, Indianapolis, IN, USA
| | - Marc Schuckit
- University of California San Diego Medical Center, San Diego, CA, USA
| | | | | | | | | | - Bernice Porjesz
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
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5
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Genetic association of KCNA5 and KCNJ3 polymorphisms in Korean children with epilepsy. Mol Cell Toxicol 2014. [DOI: 10.1007/s13273-014-0024-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Valetto A, Orsini A, Bertini V, Toschi B, Bonuccelli A, Simi F, Sammartino I, Taddeucci G, Simi P, Saggese G. Molecular cytogenetic characterization of an interstitial deletion of chromosome 21 (21q22.13q22.3) in a patient with dysmorphic features, intellectual disability and severe generalized epilepsy. Eur J Med Genet 2012; 55:362-6. [DOI: 10.1016/j.ejmg.2012.03.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 03/29/2012] [Indexed: 11/26/2022]
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Brault V, Martin B, Costet N, Bizot JC, Hérault Y. Characterization of PTZ-induced seizure susceptibility in a down syndrome mouse model that overexpresses CSTB. PLoS One 2011; 6:e27845. [PMID: 22140471 PMCID: PMC3227573 DOI: 10.1371/journal.pone.0027845] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 10/26/2011] [Indexed: 12/27/2022] Open
Abstract
Down syndrome (DS) is a complex genetic syndrome characterized by intellectual disability, dysmorphism and variable additional physiological traits. Current research progress has begun to decipher the neural mechanisms underlying cognitive impairment, leading to new therapeutic perspectives. Pentylenetetrazol (PTZ) has recently been found to have positive effects on learning and memory capacities of a DS mouse model and is foreseen to treat DS patients. But PTZ is also known to be a convulsant drug at higher dose and DS persons are more prone to epileptic seizures than the general population. This raises concerns over what long-term effects of treatment might be in the DS population. The cause of increased propensity for epilepsy in the DS population and which Hsa21 gene(s) are implicated remain unknown. Among Hsa21 candidate genes in epilepsy, CSTB, coding for the cystein protease inhibitor cystatin B, is involved in progressive myoclonus epilepsy and ataxia in both mice and human. Thus we aim to evaluate the effect of an increase in Cstb gene dosage on spontaneous epileptic activity and susceptibility to PTZ-induced seizure. To this end we generated a new mouse model trisomic for Cstb by homologous recombination. We verified that increasing copy number of Cstb from Trisomy (Ts) to Tetrasomy (Tt) was driving overexpression of the gene in the brain, we checked transgenic animals for presence of locomotor activity and electroencephalogram (EEG) abnormalities characteristic of myoclonic epilepsy and we tested if those animals were prone to PTZ-induced seizure. Overall, the results of the analysis shows that an increase in Cstb does not induce any spontaneous epileptic activity and neither increase or decrease the propensity of Ts and Tt mice to myoclonic seizures suggesting that Ctsb dosage should not interfere with PTZ-treatment.
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Affiliation(s)
- Véronique Brault
- Department of Translational Medicine and Neurogenetics, Institut de Génétique Biologie Moléculaire et Cellulaire (IGBMC), Inserm U596, CNRS UMR7104, Université de Strasbourg, Illkirch, France
| | - Benoît Martin
- Inserm U642, Rennes, France
- Laboratoire Traitement du Signal et de l'Image, Université de Rennes 1, Rennes, France
| | - Nathalie Costet
- Inserm U642, Rennes, France
- Laboratoire Traitement du Signal et de l'Image, Université de Rennes 1, Rennes, France
| | | | - Yann Hérault
- Department of Translational Medicine and Neurogenetics, Institut de Génétique Biologie Moléculaire et Cellulaire (IGBMC), Inserm U596, CNRS UMR7104, Université de Strasbourg, Illkirch, France
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, Orléans, France
- Institut Français Clinique de la Souris, GIE CERBM, Illkirch, France
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8
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Li Z, Chen Z, Lan X, Ma L, Qu Y, Liu Y, Li M, Wang P, Li F, Chen H. Two novel cSNPs of weaver gene in Chinese indigenous goat and their associations with milk yield. Mol Biol Rep 2010; 37:563-9. [PMID: 19760098 DOI: 10.1007/s11033-009-9810-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 09/02/2009] [Indexed: 10/25/2022]
Abstract
Weaver gene plays an essential physiological role in the function of many organs, including brain, heart, kidney and endocrine cells, and also in the regulation of insulin secretion by glucose and/or neurotransmitters. Thus, weaver gene is an important potential candidate gene effecting on performance traits. The objective of this study was to detect the genetic variation of five loci within weaver gene by PCR-SSCP, DNA sequencing and forced PCR-RFLP methods in 1,019 Chinese indigenous goats. Two novel coding SNPs (XM_598993:m.864G>A; XM_598993:m.1224T>A) locating on P3 and P4 loci were identified and detected by MluI and AsuII forced PCR-RFLP, respectively. In the MluI analysis, the frequencies of goat MluI-A allele in the analyzed populations were 0.226, 0.248, 0.096 and 0.088 for XNSN, GZ, SBWC and XJWC, respectively. Genotypic frequencies were found to be significantly different in four breeds (chi2 = 75.842, df = 6, P < 0.001); In the AsuII analysis, the frequencies of goat AsuII-A allele in the analyzed populations were 0.584, 0.441, 0.073 and 0.063 for XNSN, GZ, SBWC and XJWC, respectively. Genotypic frequencies were found to be significantly different among four breeds (chi2 = 399.464, df = 6, P < 0.001). The frequencies of allele MluI-A and AsuII-A in XNSN and GZ populations were significantly higher than those of SBWC and XJWC goats. Association analysis with adjusted milk yield in the XNSN breed indicated that the animals with AsuII-AA genotype owned significantly higher adjusted milk yield than the ones with AsuII-TT genotype in the second lactation (P < 0.05). The observation suggested that the allele "AsuII-A" had the positive effects on adjusted milk yield in the second lactation.
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Affiliation(s)
- Zhuanjian Li
- College of Animal Science and Technology, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi, People's Republic of China.
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Stumm G, Russ A, Nehls M. Deductive genomics: a functional approach to identify innovative drug targets in the post-genome era. AMERICAN JOURNAL OF PHARMACOGENOMICS : GENOMICS-RELATED RESEARCH IN DRUG DEVELOPMENT AND CLINICAL PRACTICE 2003; 2:263-71. [PMID: 12421097 DOI: 10.2165/00129785-200202040-00006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The sequencing of the human genome has generated a drug discovery process that is based on sequence analysis and hypothesis-driven (inductive) prediction of gene function. This approach, which we term inductive genomics, is currently dominating the efforts of the pharmaceutical industry to identify new drug targets. According to recent studies, this sequence-driven discovery process is paradoxically increasing the average cost of drug development, thus falling short of the promise of the Human Genome Project to simplify the creation of much needed novel therapeutics. In the early stages of discovery, the flurry of new gene sequences makes it difficult to pick and prioritize the most promising product candidates for product development, as with existing technologies important decisions have to be based on circumstantial evidence that does not strongly predict therapeutic potential. This is because the physiological function of a potential target cannot be predicted by gene sequence analysis and in vitro technologies alone. In contrast, deductive genomics, or large-scale forward genetics, bridges the gap between sequence and function by providing a function-driven in vivo screen of a highly orthologous mammalian model genome for medically relevant physiological functions and drug targets. This approach allows drug discovery to move beyond the focus on sequence-driven identification of new members of classical drug-able protein families towards the biology-driven identification of innovative targets and biological pathways.
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Neusch C, Weishaupt JH, Bähr M. Kir channels in the CNS: emerging new roles and implications for neurological diseases. Cell Tissue Res 2003; 311:131-8. [PMID: 12596033 DOI: 10.1007/s00441-002-0669-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2002] [Accepted: 11/06/2002] [Indexed: 01/01/2023]
Abstract
Inwardly rectifying potassium (Kir) channels have long been regarded as transmembrane proteins that regulate the membrane potential of neurons and that are responsible for [K(+)] siphoning in glial cells. The subunit diversity within the Kir channel family is growing rapidly and this is reflected in the multitude of roles that Kir channels play in the central nervous system (CNS). Kir channels are known to control cell differentiation, modify CNS hormone secretion, modulate neurotransmitter release in the nigrostriatal system, may act as hypoxia-sensors and regulate cerebral artery dilatation. The increasing availability of genetic mouse models that express inactive Kir channel subunits has opened new insights into their role in developing and adult mammalian tissues and during the course of CNS disorders. New aspects with respect to the role of Kir channels during CNS cell differentiation and neurogenesis are also emerging. Dysfunction of Kir channels in animal models can lead to severe phenotypes ranging from early postnatal death to an increased susceptibility to develop epileptic seizures. In this review, we summarize the in vivo data that demonstrate the role of Kir channels in regulating morphogenetic events, such as the proliferation, differentiation and survival of neurons and glial cells. We describe the way in which the gating of Kir channel subunits plays an important role in polygenic CNS diseases, such as white matter disease, epilepsy and Parkinson's disease.
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Affiliation(s)
- C Neusch
- Department of Neurology, Georg-August University, Robert-Koch-Str 40, 37075 Göttingen, Germany.
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Chioza B, Osei-Lah A, Wilkie H, Nashef L, McCormick D, Asherson P, Makoff AJ. Suggestive evidence for association of two potassium channel genes with different idiopathic generalised epilepsy syndromes. Epilepsy Res 2002; 52:107-16. [PMID: 12458027 DOI: 10.1016/s0920-1211(02)00195-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several potassium channel genes have been implicated in epilepsy. We have investigated three such genes, KCNJ3, KCNJ6 and KCNQ2, by association studies using a broad sample of idiopathic generalised epilepsy (IGE) unselected by syndrome. One of the two single nucleotide polymorphisms (SNPs) examined in one of the inward rectifying potassium channel genes, KCNJ3, was associated with IGE by genotype (P=0.0097), while its association by allele was of borderline significance (P=0.051). Analysis of the different clinical subgroups within the IGE sample showed more significant association with the presence of absence seizures (P=0.0041) and which is still significant after correction for multiple testing. Neither SNP in the other rectifying potassium channel gene, KCNJ6, was associated with IGE or any subgroup. None of the three SNPs in the voltage-gated potassium channel gene, KCNQ2, was associated with IGE. However, one SNP was associated with epilepsy with generalised tonic clonic seizures only (P=0.016), as was an SNP approximately 56 kb distant in the closely linked nicotinic acetylcholine gene CHRNA4 (P=0.014). These two SNPs were not in linkage disequilibrium with each other, suggesting that if they are not true associations they have independently occurred by chance. Neither association remains significant after correcting for multiple testing.
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Affiliation(s)
- B Chioza
- Department of Psychological Medicine, Institute of Psychiatry, Denmark Hill, London, UK
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12
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Lerche H, Jurkat-Rott K, Lehmann-Horn F. Ion channels and epilepsy. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 106:146-59. [PMID: 11579435 DOI: 10.1002/ajmg.1582] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ion channels provide the basis for the regulation of excitability in the central nervous system and in other excitable tissues such as skeletal and heart muscle. Consequently, mutations in ion channel encoding genes are found in a variety of inherited diseases associated with hyper- or hypoexcitability of the affected tissue, the so-called 'channelopathies.' An increasing number of epileptic syndromes belongs to this group of rare disorders: Autosomal dominant nocturnal frontal lobe epilepsy is caused by mutations in a neuronal nicotinic acetylcholine receptor (affected genes: CHRNA4, CHRNB2), benign familial neonatal convulsions by mutations in potassium channels constituting the M-current (KCNQ2, KCNQ3), generalized epilepsy with febrile seizures plus by mutations in subunits of the voltage-gated sodium channel or the GABA(A) receptor (SCN1B, SCN1A, GABRG2), and episodic ataxia type 1-which is associated with epilepsy in a few patients--by mutations within another voltage-gated potassium channel (KCNA1). These rare disorders provide interesting models to study the etiology and pathophysiology of disturbed excitability in molecular detail. On the basis of genetic and electrophysiologic studies of the channelopathies, novel therapeutic strategies can be developed, as has been shown recently for the antiepileptic drug retigabine activating neuronal KCNQ potassium channels.
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MESH Headings
- Ataxia/genetics
- Ataxia/metabolism
- Epilepsies, Myoclonic/genetics
- Epilepsies, Myoclonic/metabolism
- Epilepsies, Partial/genetics
- Epilepsies, Partial/metabolism
- Epilepsy/genetics
- Epilepsy/metabolism
- Epilepsy/therapy
- Epilepsy, Benign Neonatal/genetics
- Epilepsy, Benign Neonatal/metabolism
- Epilepsy, Frontal Lobe/genetics
- Epilepsy, Frontal Lobe/metabolism
- Epilepsy, Generalized/genetics
- Epilepsy, Generalized/metabolism
- Genes, Dominant
- Humans
- Ion Channel Gating
- Ion Channels/chemistry
- Ion Channels/genetics
- Ion Channels/metabolism
- Mutation
- Myokymia/genetics
- Myokymia/metabolism
- Seizures, Febrile/genetics
- Seizures, Febrile/metabolism
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Affiliation(s)
- H Lerche
- Department of Applied Physiology, Univeristy of Ulm, Germany
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