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Abstract
Idiopathic generalized epilepsies (IGE) are characterized by normal background EEG activity and generalized interictal spike-and-wave discharges in the absence of any evidence of brain lesion. Absence epilepsies are the prototypes of IGEs. In childhood and juvenile absence epilepsies, by definition, all patients manifest absence seizures associated with an EEG pattern of generalized spike-wave (GSW) discharges. In juvenile myoclonic epilepsy, myoclonic jerks, usually affecting shoulders and arms bilaterally and appearing upon awakening, are the most characteristic clinical feature. Myoclonic jerks are accompanied on the EEG by generalized spike/polyspike-and-wave (GSW, GPWS) complexes at 3.5-6Hz. Idiopathic generalized epilepsy with generalized tonic-clonic seizures only is a broad and nonspecific category including all patients with generalized tonic-clonic seizures and an interictal EEG pattern of GSW discharges. Despite the strong heritability and the recent advances in genetic technology, the genetic basis of IGEs remains largely elusive and only in a small minority of patients with classic IGE phenotypes is a monogenic cause identified. Early myoclonic encephalopathy (EME), early infantile encephalopathy with suppression bursts, West syndrome, and Lennox-Gastaut syndrome, once classified among the generalized epilepsies, are now considered to be epileptic encephalopathies. Among them, only Lennox-Gastaut syndrome is characterized by prominent generalized clinical and EEG features.
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Affiliation(s)
- Renzo Guerrini
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy.
| | - Carla Marini
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Carmen Barba
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy
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Expression Analysis of CYFIP1 and CAMKK2 Genes in the Blood of Epileptic and Schizophrenic Patients. J Mol Neurosci 2018; 65:336-342. [PMID: 29992499 DOI: 10.1007/s12031-018-1106-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/15/2018] [Indexed: 12/27/2022]
Abstract
Schizophrenia and epilepsy are two prevalent neurological disorders with high global burden to the society. Genome-wide studies have identified potential underlying causes for these neurological diseases. In the present case-control study, we have assessed expression of CYFIP1 and CAMKK2 genes in the blood samples of epileptic and schizophrenic patients compared with healthy subjects. A total of 180 subjects including 40 epileptic patients, 50 schizophrenic patients, and 90 healthy individuals participated in the study. Expression of the mentioned genes was measured using TaqMan real-time PCR. The results demonstrated a significant upregulation of CYFIP1 gene expression in epileptic patients (P = 0.029). CAMKK2 was downregulated in female schizophrenic patients compared with female healthy individuals (P = 0.048). These results may provide new insight into the pathogenesis of epilepsy and schizophrenia and suggest these genes as potential therapeutic targets for these neurological disorders. Future studies should evaluate these results in larger cohorts of patients.
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Lee CG, Lee J, Lee M. Multi-gene panel testing in Korean patients with common genetic generalized epilepsy syndromes. PLoS One 2018; 13:e0199321. [PMID: 29924869 PMCID: PMC6010271 DOI: 10.1371/journal.pone.0199321] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
Genetic heterogeneity of common genetic generalized epilepsy syndromes is frequently considered. The present study conducted a focused analysis of potential candidate or susceptibility genes for common genetic generalized epilepsy syndromes using multi-gene panel testing with next-generation sequencing. This study included patients with juvenile myoclonic epilepsy, juvenile absence epilepsy, and epilepsy with generalized tonic-clonic seizures alone. We identified pathogenic variants according to the American College of Medical Genetics and Genomics guidelines and identified susceptibility variants using case-control association analyses and family analyses for familial cases. A total of 57 patients were enrolled, including 51 sporadic cases and 6 familial cases. Twenty-two pathogenic and likely pathogenic variants of 16 different genes were identified. CACNA1H was the most frequently observed single gene. Variants of voltage-gated Ca2+ channel genes, including CACNA1A, CACNA1G, and CACNA1H were observed in 32% of variants (n = 7/22). Analyses to identify susceptibility variants using case-control association analysis indicated that KCNMA1 c.400G>C was associated with common genetic generalized epilepsy syndromes. Only 1 family (family A) exhibited a candidate pathogenic variant p.(Arg788His) on CACNA1H, as determined via family analyses. This study identified candidate genetic variants in about a quarter of patients (n = 16/57) and an average of 2.8 variants was identified in each patient. The results reinforced the polygenic disorder with very high locus and allelic heterogeneity of common GGE syndromes. Further, voltage-gated Ca2+ channels are suggested as important contributors to common genetic generalized epilepsy syndromes. This study extends our comprehensive understanding of common genetic generalized epilepsy syndromes.
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Affiliation(s)
- Cha Gon Lee
- Department of Pediatrics, Nowon Eulji Medical Center, Eulji University, Seoul, Republic of Korea
| | - Jeehun Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
- * E-mail:
| | - Munhyang Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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Becker F, Reid CA, Hallmann K, Tae HS, Phillips AM, Teodorescu G, Weber YG, Kleefuss-Lie A, Elger C, Perez-Reyes E, Petrou S, Kunz WS, Lerche H, Maljevic S. Functional variants in HCN4 and CACNA1H may contribute to genetic generalized epilepsy. Epilepsia Open 2017; 2:334-342. [PMID: 29588962 PMCID: PMC5862120 DOI: 10.1002/epi4.12068] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2017] [Indexed: 01/11/2023] Open
Abstract
Objective Genetic generalized epilepsy (GGE) encompasses seizure disorders characterized by spike‐and‐wave discharges (SWD) originating within thalamo‐cortical circuits. Hyperpolarization‐activated (HCN) and T‐type Ca2+ channels are key modulators of rhythmic activity in these brain regions. Here, we screened HCN4 and CACNA1H genes for potentially contributory variants and provide their functional analysis. Methods Targeted gene sequencing was performed in 20 unrelated familial cases with different subtypes of GGE, and the results confirmed in 230 ethnically matching controls. Selected variants in CACNA1H and HCN4 were functionally assessed in tsA201 cells and Xenopus laevis oocytes, respectively. Results We discovered a novel CACNA1H (p.G1158S) variant in two affected members of a single family. One of them also carried an HCN4 (p.P1117L) variant inherited from the unaffected mother. In a separate family, an HCN4 variant (p.E153G) was identified in one of several affected members. Voltage‐clamp analysis of CACNA1H (p.G1158S) revealed a small but significant gain‐of‐function, including increased current density and a depolarizing shift of steady‐state inactivation. HCN4 p.P1117L and p.G153E both caused a hyperpolarizing shift in activation and reduced current amplitudes, resulting in a loss‐of‐function. Significance Our results are consistent with a model suggesting cumulative contributions of subtle functional variations in ion channels to seizure susceptibility and GGE.
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Affiliation(s)
- Felicitas Becker
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,RKU-University Neurology Clinic of Ulm Ulm Germany
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Kerstin Hallmann
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Han-Shen Tae
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,Present address: Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong Wollongong New South Wales Australia
| | - A Marie Phillips
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,School of Biosciences The University of Melbourne Melbourne Victoria Australia
| | - Georgeta Teodorescu
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Yvonne G Weber
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Ailing Kleefuss-Lie
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Christian Elger
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Edward Perez-Reyes
- Department of Pharmacology University of Virginia Charlottesville Virginia U.S.A
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Wolfram S Kunz
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Holger Lerche
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Snezana Maljevic
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
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dos Santos BP, Marinho CRM, Marques TEBS, Angelo LKG, Malta MVDS, Duzzioni M, de Castro OW, Leite JP, Barbosa FT, Gitaí DLG. Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies. PLoS One 2017; 12:e0179629. [PMID: 28636645 PMCID: PMC5479548 DOI: 10.1371/journal.pone.0179629] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Several genetic association investigations have been performed over the last three decades to identify variants underlying Juvenile Myoclonic Epilepsy (JME). Here, we evaluate the accumulating findings and provide an updated perspective of these studies. METHODOLOGY A systematic literature search was conducted using the PubMed, Embase, Scopus, Lilacs, epiGAD, Google Scholar and Sigle up to February 12, 2016. The quality of the included studies was assessed by a score and classified as low and high quality. Beyond outcome measures, information was extracted on the setting for each study, characteristics of population samples and polymorphisms. RESULTS Fifty studies met eligibility criteria and were used for data extraction. With a single exception, all studies used a candidate gene approach, providing data on 229 polymorphisms in or near 55 different genes. Of variants investigating in independent data sets, only rs2029461 SNP in GRM4, rs3743123 in CX36 and rs3918149 in BRD2 showed a significant association with JME in at least two different background populations. The lack of consistent associations might be due to variations in experimental design and/or limitations of the approach. CONCLUSIONS Thus, despite intense research evidence established, specific genetic variants in JME susceptibility remain inconclusive. We discussed several issues that may compromise the quality of the results, including methodological bias, endophenotype and potential involvement of epigenetic factors. PROSPERO REGISTRATION NUMBER CRD42016036063.
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Affiliation(s)
- Bruna Priscila dos Santos
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Chiara Rachel Maciel Marinho
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | | | - Layanne Kelly Gomes Angelo
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Maísa Vieira da Silva Malta
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Marcelo Duzzioni
- Department of Pharmacology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Olagide Wagner de Castro
- Department of Physiology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - João Pereira Leite
- Division of Neurology, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Daniel Leite Góes Gitaí
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
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Strehlow V, Swinkels MEM, Thomas RH, Rapps N, Syrbe S, Dorn T, Lemke JR. Generalized Epilepsy and Myoclonic Seizures in 22q11.2 Deletion Syndrome. Mol Syndromol 2016; 7:239-246. [PMID: 27781034 DOI: 10.1159/000448445] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prompted by the observations of juvenile myoclonic epilepsy (JME) in 22q11.2 deletion syndrome (22q11DS) and recurrent copy number variants in genetic generalized epilepsy (GGE), we searched for further evidence supporting a possible correlation of 22q11DS with GGE and with myoclonic seizures. Through routine diagnostics, we identified 3 novel individuals with the seemingly uncommon combination of 22q11DS and JME. We subsequently screened the literature for reports focussing on the epilepsy phenotype in 22q11DS. We additionally screened a database of 173 22q11DS patients and identified a fourth individual with JME as well as 2 additional cases with GGE. We describe 6 novel and 22 published cases with co-occurrence of 22q11DS and GGE. In many patients, GGE was associated with myoclonic seizures allowing for a diagnosis of JME in at least 6 individuals. Seventeen of the 173 22q11DS cases (10%) had a diagnosis of either focal or generalized epilepsy. In these cases, focal epilepsy could often be attributed to syndrome-associated hypocalcaemia, cerebral bleeds, or structural brain anomalies. However, the cause of GGE remained unclear. In this study, we describe and review 28 individuals with 22q11DS and GGE (especially JME), showing that both disorders frequently co-occur. Compared to the reported prevalence of 15-21%, in our case series only 10% of 22q11DS individuals were found to have epilepsy, often GGE. Since 22q11.2 does not contain convincing GGE candidate genes, we discuss the possibility of an aetiological correlation through a possibly disturbed interaction with the GABAB receptor.
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Affiliation(s)
- Vincent Strehlow
- Institute of Human Genetics, University Hospital and Clinics, Leipzig, Germany
| | - Marielle E M Swinkels
- Department of Biomedical Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Rhys H Thomas
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Nora Rapps
- Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany
| | - Steffen Syrbe
- Department of Women and Child Health, Hospital for Children and Adolescents, University Hospital and Clinics, Leipzig, Germany; Division of Child Neurology and Inherited Metabolic Diseases, Department of General Paediatrics, Centre for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | | | - Johannes R Lemke
- Institute of Human Genetics, University Hospital and Clinics, Leipzig, Germany
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Sapio MR, Vessaz M, Thomas P, Genton P, Fricker LD, Salzmann A. Novel carboxypeptidase A6 (CPA6) mutations identified in patients with juvenile myoclonic and generalized epilepsy. PLoS One 2015; 10:e0123180. [PMID: 25875328 PMCID: PMC4395397 DOI: 10.1371/journal.pone.0123180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/17/2015] [Indexed: 01/12/2023] Open
Abstract
Carboxypeptidase A6 (CPA6) is a peptidase that removes C-terminal hydrophobic amino acids from peptides and proteins. The CPA6 gene is expressed in the brains of humans and animals, with high levels of expression during development. It is translated with a prodomain (as proCPA6), which is removed before secretion. The active form of CPA6 binds tightly to the extracellular matrix (ECM) where it is thought to function in the processing of peptides and proteins. Mutations in the CPA6 gene have been identified in patients with temporal lobe epilepsy and febrile seizures. In the present study, we screened for CPA6 mutations in patients with juvenile myoclonic epilepsy and identified two novel missense mutations: Arg36His and Asn271Ser. Patients harboring these mutations also presented with generalized epilepsy. Neither of the novel mutations was found in a control population. Asn271 is highly conserved in CPA6 and other related metallocarboxypeptidases. Arg36 is present in the prodomain and is not highly conserved. To assess structural consequences of the amino acid substitutions, both mutants were modeled within the predicted structure of the enzyme. To examine the effects of these mutations on enzyme expression and activity, we expressed the mutated enzymes in human embryonic kidney 293T cells. These analyses revealed that Asn271Ser abolished enzymatic activity, while Arg36His led to a ~50% reduction in CPA6 levels in the ECM. Pulse-chase using radio-labeled amino acids was performed to follow secretion. Newly-synthesized CPA6 appeared in the ECM with peak levels between 2-8 hours. There was no major difference in time course between wild-type and mutant forms, although the amount of radiolabeled CPA6 in the ECM was lower for the mutants. Our experiments demonstrate that these mutations in CPA6 are deleterious and provide further evidence for the involvement of CPA6 mutations in the predisposition for several types of epilepsy.
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Affiliation(s)
- Matthew R. Sapio
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Monique Vessaz
- Department of Genetic Medicine and Laboratory, University Hospitals of Geneva, Geneva, Switzerland
| | - Pierre Thomas
- Department of Neurology, University Hospital, Nice, France
| | - Pierre Genton
- Centre Saint Paul, Hôpital Henri Gastaut, Marseille, France
| | - Lloyd D. Fricker
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States of America
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States of America
- * E-mail: (LDF); (AS)
| | - Annick Salzmann
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
- * E-mail: (LDF); (AS)
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Cox DM, Butler MG. The 15q11.2 BP1-BP2 microdeletion syndrome: a review. Int J Mol Sci 2015; 16:4068-82. [PMID: 25689425 PMCID: PMC4346944 DOI: 10.3390/ijms16024068] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/03/2015] [Accepted: 02/10/2015] [Indexed: 11/16/2022] Open
Abstract
Patients with the 15q11.2 BP1–BP2 microdeletion can present with developmental and language delay, neurobehavioral disturbances and psychiatric problems. Autism, seizures, schizophrenia and mild dysmorphic features are less commonly seen. The 15q11.2 BP1–BP2 microdeletion involving four genes (i.e., TUBGCP5, CYFIP1, NIPA1, NIPA2) is emerging as a recognized syndrome with a prevalence ranging from 0.57%–1.27% of patients presenting for microarray analysis which is a two to four fold increase compared with controls. Review of clinical features from about 200 individuals were grouped into five categories and included developmental (73%) and speech (67%) delays; dysmorphic ears (46%) and palatal anomalies (46%); writing (60%) and reading (57%) difficulties, memory problems (60%) and verbal IQ scores ≤75 (50%); general behavioral problems, unspecified (55%) and abnormal brain imaging (43%). Other clinical features noted but not considered as common were seizures/epilepsy (26%), autism spectrum disorder (27%), attention deficit disorder (ADD)/attention deficit hyperactivity disorder (ADHD) (35%), schizophrenia/paranoid psychosis (20%) and motor delay (42%). Not all individuals with the deletion are clinically affected, yet the collection of findings appear to share biological pathways and presumed genetic mechanisms. Neuropsychiatric and behavior disturbances and mild dysmorphic features are associated with genomic imbalances of the 15q11.2 BP1–BP2 region, including microdeletions, but with an apparent incomplete penetrance and variable expressivity.
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Affiliation(s)
- Devin M Cox
- Departments of Psychiatry & Behavioral Sciences, University of Kansas Medical Center, 3901 Rainbow Boulevard, MS 4015, Kansas City, KS 66160, USA.
| | - Merlin G Butler
- Departments of Psychiatry & Behavioral Sciences, University of Kansas Medical Center, 3901 Rainbow Boulevard, MS 4015, Kansas City, KS 66160, USA.
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10
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6q22.1 microdeletion and susceptibility to pediatric epilepsy. Eur J Hum Genet 2014; 23:173-9. [PMID: 24824130 DOI: 10.1038/ejhg.2014.75] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/04/2014] [Accepted: 03/07/2014] [Indexed: 12/31/2022] Open
Abstract
Genomic copy-number variations (CNVs) constitute an important cause of epilepsies and other human neurological disorders. Recent advancement of technologies integrating genome-wide CNV mapping and sequencing is rapidly expanding the molecular field of pediatric neurodevelopmental disorders. In a previous study, a novel epilepsy locus was identified on 6q16.3q22.31 by linkage analysis in a large pedigree. Subsequent array comparative genomic hybridization (array CGH) analysis of four unrelated cases narrowed this region to ∼5 Mb on 6q22.1q22.31. We sought to further narrow the critical region on chromosome 6q22. Array CGH analysis was used in genome-wide screen for CNVs of a large cohort of patients with neurological abnormalities. Long-range PCR and DNA sequencing were applied to precisely map chromosomal deletion breakpoints. Finally, real-time qPCR was used to estimate relative expression in the brain of the candidate genes. We identified six unrelated patients with overlapping microdeletions within 6q22.1q22.31 region, three of whom manifested seizures. Deletions were found to be de novo in 5/6 cases, including all subjects presenting with seizures. We sequenced the deletion breakpoints in four patients and narrowed the critical region to a ∼250-kb segment at 6q22.1 that includes NUS1, several expressed sequence tags (ESTs) that are highly expressed in the brain, and putative regulatory sequences of SLC35F1. Our findings indicate that dosage alteration in particular, of NUS1, EST AI858607, or SLC35F1 are important contributors to the neurodevelopmental phenotype associated with 6q22 deletion, including epilepsy and tremors.
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Rees E, Walters JTR, Georgieva L, Isles AR, Chambert KD, Richards AL, Mahoney-Davies G, Legge SE, Moran JL, McCarroll SA, O'Donovan MC, Owen MJ, Kirov G. Analysis of copy number variations at 15 schizophrenia-associated loci. Br J Psychiatry 2014; 204:108-14. [PMID: 24311552 PMCID: PMC3909838 DOI: 10.1192/bjp.bp.113.131052] [Citation(s) in RCA: 290] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/12/2013] [Accepted: 09/05/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND A number of copy number variants (CNVs) have been suggested as susceptibility factors for schizophrenia. For some of these the data remain equivocal, and the frequency in individuals with schizophrenia is uncertain. AIMS To determine the contribution of CNVs at 15 schizophrenia-associated loci (a) using a large new data-set of patients with schizophrenia (n = 6882) and controls (n = 6316), and (b) combining our results with those from previous studies. METHOD We used Illumina microarrays to analyse our data. Analyses were restricted to 520 766 probes common to all arrays used in the different data-sets. RESULTS We found higher rates in participants with schizophrenia than in controls for 13 of the 15 previously implicated CNVs. Six were nominally significantly associated (P<0.05) in this new data-set: deletions at 1q21.1, NRXN1, 15q11.2 and 22q11.2 and duplications at 16p11.2 and the Angelman/Prader-Willi Syndrome (AS/PWS) region. All eight AS/PWS duplications in patients were of maternal origin. When combined with published data, 11 of the 15 loci showed highly significant evidence for association with schizophrenia (P<4.1×10(-4)). CONCLUSIONS We strengthen the support for the majority of the previously implicated CNVs in schizophrenia. About 2.5% of patients with schizophrenia and 0.9% of controls carry a large, detectable CNV at one of these loci. Routine CNV screening may be clinically appropriate given the high rate of known deleterious mutations in the disorder and the comorbidity associated with these heritable mutations.
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Affiliation(s)
- Elliott Rees
- Elliott Rees, MRes, James T. R. Walters, PhD, MRCPsych, Lyudmila Georgieva, PhD, Anthony R. Isles, PhD, MRC, Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK; Kimberly D. Chambert, MS, Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, Massachuetts, USA; Alexander L. Richards, PhD, Gerwyn Mahoney-Davies, BSc, Sophie E. Legge, BSc, Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK; Jennifer L. Moran, PhD, Steven A. McCarroll, PhD, Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, Massachuetts, USA; Michael C. O'Donovan, FRCPsych, PhD, Michael J. Owen, FRCPsych, PhD, George Kirov, MRCPsych, PhD, Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK
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Helbig I, Hartmann C, Mefford HC. Clarifying the role of the 22q11.2 microdeletion in juvenile myoclonic epilepsy. Epilepsy Behav 2013; 29:589-90. [PMID: 24090771 DOI: 10.1016/j.yebeh.2013.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 01/31/2023]
Affiliation(s)
- Ingo Helbig
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Kiel Campus, Arnold-Heller-Str. 3, Building 9, 24105 Kiel, Germany.
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Piccione M, Vecchio D, Salzano E, Corsello G. Delineating a new critical region for juvenile myoclonic epilepsy at the 22q11.2 chromosome. Epilepsy Behav 2013; 29:587-8. [PMID: 24012507 DOI: 10.1016/j.yebeh.2013.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 08/09/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Maria Piccione
- Department of Sciences for Health Promotion and Mother and Child Care, University of Palermo, Palermo, Italy.
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