51
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Mukherjee K, Patel PA, Rajan DS, LaConte LEW, Srivastava S. Survival of a male patient harboring CASK Arg27Ter mutation to adolescence. Mol Genet Genomic Med 2020; 8:e1426. [PMID: 32696595 PMCID: PMC7549553 DOI: 10.1002/mgg3.1426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/01/2020] [Accepted: 07/02/2020] [Indexed: 02/06/2023] Open
Abstract
Background CASK is an X‐linked gene in mammals and its deletion in males is incompatible with life. CASK heterozygous mutations in female patients associate with intellectual disability, microcephaly, pontocerebellar hypoplasia, and optic nerve hypoplasia, whereas CASK hemizygous mutations in males manifest as early infantile epileptic encephalopathy with a grim prognosis. Here, we report a rare case of survival of a male patient harboring a CASK null mutation to adolescent age. Methods Trio whole exome sequencing analysis was performed from blood genomic DNA. Magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and electroencephalogram (EEG) analyses were performed to determine anomalies in brain development, metabolite concentrations, and electrical activity, respectively. Results Trio‐WES analysis identified a de novo c.79C>T (p.Arginine27Ter) mutation in CASK causing a premature translation termination at the very N‐terminus of the protein. The 17‐years, and 11‐month‐old male patient displayed profound intellectual disability, microcephaly, dysmorphism, ponto‐cerebellar hypoplasia, and intractable epilepsy. His systemic symptoms included overall reduced somatic growth, dysautonomia, ventilator and G tube dependence, and severe osteopenia. Brain MRI revealed a severe cerebellar and brain stem hypoplasia with progressive cerebral atrophy. EEG spectral analysis revealed a global functional defect with generalized background slowing and delta waves dominating even in the awake state. Conclusion This case study is the first to report survival of a male patient carrying a CASK loss‐of‐function mutation to adolescence and highlights that improved palliative care could extend survival. Moreover, the genomic position encoding Arg27 in CASK may possess an increased susceptibility to mutations.
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Affiliation(s)
- Konark Mukherjee
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Paras A Patel
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Deepa S Rajan
- Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh, Pittsburgh, PA, USA
| | - Leslie E W LaConte
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Sarika Srivastava
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA.,Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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Abstract
Epilepsy and autism frequently co-occur. Epilepsy confers an increased risk of autism and autism confers an increased risk of epilepsy. Specific epilepsy syndromes, intellectual disability, and female gender present a particular risk of autism in individuals with epilepsy. Epilepsy and autism are likely to share common etiologies, which predispose individuals to either or both conditions. Genetic factors, metabolic disorders, mitochondrial disorders, and immune dysfunction all can be implicated.
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Affiliation(s)
- Frank M C Besag
- East London NHS Foundation Trust, 5-7 Rush Court, Bedford MK40 3JT, UK; University College London, London, UK; King's College London, London, UK.
| | - Michael J Vasey
- East London NHS Foundation Trust, 5-7 Rush Court, Bedford MK40 3JT, UK
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53
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Genotype-phenotype correlates of infantile-onset developmental & epileptic encephalopathy syndromes in South India: A single centre experience. Epilepsy Res 2020; 166:106398. [PMID: 32593896 DOI: 10.1016/j.eplepsyres.2020.106398] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/29/2020] [Accepted: 06/10/2020] [Indexed: 11/23/2022]
Abstract
INTRODUCTION A paucity of literature exists on genotype- phenotype correlates of 'unknown-etiology' infantile-onset developmental-epileptic encephalopathies (DEE) from India. The primary objective was to explore the yield of genetic testing in identifying potential disease causing variants in electro-clinical phenotypes of DEE METHODS: An observational hospital-based study was undertaken on children with unexplained refractory seizure-onset ≤12 months age and developmental delay, whose families consented and underwent genetic testing during a three year time period (2016-2018) by next-generation sequencing (NGS) or multiplex ligand protein amplification. Yield was considered based on demonstration of pathogenic/likely pathogenic variants only and variants of unknown significance (VUS) were documented. RESULTS Pathogenic/likely pathogenic variants were identified in 26 (31.7 %) out of 82 children with DEE. These included those variants responsible for primarily DEE- 21(76.7 %); neuro-metabolic disorders- 3(18.6 %) and chromosomal deletions- 2(4.7 %). Of these patients, early-infantile epilepsy onset ≤ 6 months age was noted in 22(84.6 %). The DEE studied included Ohtahara syndrome associated with STXBP1 and SCN8A variants with yield of 50 % (2/4 tested); early myoclonic encephalopathy (no yield in 2); West syndrome with CDKL5, yield of 13.3 % (2/15 tested); epilepsy of infancy with migrating partial seizures due to CACNA1A and KCNT1 variants, yield of 67 % (2/3 tested); DEE-unclassified with KCNQ2, AP3B2, ZEB2, metabolic variants (SUOX, ALDH7A1, GLDC) and chromosome deletions (chr 1p36, chr2q24.3); yield of 32 % (8/25 tested). Patients with Dravet syndrome/Dravet-like phenotypes (N = 33) had variants in SCN1A (N = 10), SCN1B, CHD2; yield of 36.4 % (12/33 tested; 57.1 % from NGS). Eighteen patients with potential variants (SCN1A, SCN2A, SCN8A, KCNQ2, ALDH7A1 which also included VUS) could be offered targeted therapy. CONCLUSIONS Our study confirms a good yield of genetic testing in neonatal and infantile-onset DEE provided robust phenotyping of infants is attempted with prognostic and therapeutic implications, particularly relevant to centres with resource constraints.
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54
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Specchio N, Pietrafusa N, Ferretti A, De Palma L, Santarone ME, Pepi C, Trivisano M, Vigevano F, Curatolo P. Treatment of infantile spasms: why do we know so little? Expert Rev Neurother 2020; 20:551-566. [PMID: 32316776 DOI: 10.1080/14737175.2020.1759423] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Infantile spasm (IS) is an epileptic syndrome with typical onset within the first 2 years of life. This condition might be caused by several etiologies. IS is associated with pathological neuronal networks; however, definite hypotheses on neurobiological processes are awaited. AREAS COVERED Changes in NMDA and GABAB receptors and increase of Ca2+ conductance are some of the possible pathophysiological mechanisms. Animal models can help, but most have only some features of IS. Outcome is strongly affected by etiology and the timing of treatment, which relies still on ACTH, oral steroids, and vigabatrin. No significant differences in terms of efficacy have been documented, though a combination of ACTH and vigabatrin seems to be associated with better long-term outcomes. Despite the increasing knowledge about the etiology and pathophysiology of IS, in the last years, no new treatment approaches have been recognized to be able to modify the neurobiological process underlying IS. Precision medicine has far to come in IS. EXPERT OPINION Recently, no new therapeutic options for IS have emerged, probably due to the lack of reliable animal models and to the extreme variability in etiologies. Consequently, the outlook for patients and families is poor and early recognition and intervention remain research priorities.
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy.,Member of European Reference Network EpiCARE
| | - Nicola Pietrafusa
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy
| | - Alessandro Ferretti
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy
| | - Luca De Palma
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy
| | - Marta Elena Santarone
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , 00165, Rome, Italy
| | - Chiara Pepi
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy.,Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University , 00133, Rome, Italy
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , Rome, 00165, Italy
| | - Federico Vigevano
- Member of European Reference Network EpiCARE.,Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS , 00165, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University , 00133, Rome, Italy
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55
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Rech ME, McCarthy JM, Chen CA, Edmond JC, Shah VS, Bosch DGM, Berry GT, Williams L, Madan-Khetarpal S, Niyazov D, Shaw-Smith C, Kovar EM, Lupo PJ, Schaaf CP. Phenotypic expansion of Bosch-Boonstra-Schaaf optic atrophy syndrome and further evidence for genotype-phenotype correlations. Am J Med Genet A 2020; 182:1426-1437. [PMID: 32275123 DOI: 10.1002/ajmg.a.61580] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/06/2020] [Accepted: 03/13/2020] [Indexed: 12/17/2022]
Abstract
Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS) is an autosomal dominant neurodevelopmental disorder caused by loss-of-function variants in NR2F1 and characterized by visual impairment, developmental delay, and intellectual disability. Here we report 18 new cases, provide additional clinical information for 9 previously reported individuals, and review an additional 27 published cases to present a total of 54 patients. Among these are 22 individuals with point mutations or in-frame deletions in the DNA-binding domain (DBD), and 32 individuals with other types of variants including whole-gene deletions, nonsense and frameshift variants, and point mutations outside the DBD. We corroborate previously described clinical characteristics including developmental delay, intellectual disability, autism spectrum disorder diagnoses/features thereof, cognitive/behavioral anomalies, hypotonia, feeding difficulties, abnormal brain MRI findings, and seizures. We also confirm a vision phenotype that includes optic nerve hypoplasia, optic atrophy, and cortical visual impairment. Additionally, we expand the vision phenotype to include alacrima and manifest latent nystagmus (fusional maldevelopment), and we broaden the behavioral phenotypic spectrum to include a love of music, an unusually good long-term memory, sleep difficulties, a high pain tolerance, and touch sensitivity. Furthermore, we provide additional evidence for genotype-phenotype correlations, specifically supporting a more severe phenotype associated with DBD variants.
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Affiliation(s)
- Megan E Rech
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - John M McCarthy
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Chun-An Chen
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jane C Edmond
- Department of Ophthalmology, Dell Medical School, University of Texas at Austin, Austin, Texas, USA.,Division of Ophthalmology, Texas Children's Hospital, Houston, Texas, USA.,Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
| | - Veeral S Shah
- Division of Ophthalmology, Texas Children's Hospital, Houston, Texas, USA.,Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
| | - Daniëlle G M Bosch
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gerard T Berry
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Linford Williams
- Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
| | | | - Dmitriy Niyazov
- Department of Pediatrics, Ochsner Health System and University of Queensland, New Orleans, Louisiana, USA
| | - Charles Shaw-Smith
- Department of Clinical Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Erin M Kovar
- Section of Hematology and Oncology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Philip J Lupo
- Section of Hematology and Oncology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Christian P Schaaf
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Heidelberg University, Institute of Human Genetics, Heidelberg, Germany
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56
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Abstract
Developmental and epileptic encephalopathies (DEEs) can be primarily attributed to genetic causes. The genetic landscape of DEEs has been largely shaped by the rise of high-throughput sequencing, which led to the discovery of new DEE-associated genes and helped identify de novo pathogenic variants. We discuss briefly the contribution of de novo variants to DEE and also focus on alternative inheritance models that contribute to DEE. First, autosomal recessive inheritance in outbred populations may have a larger contribution than previously appreciated, accounting for up to 13% of DEEs. A small subset of genes that typically harbor de novo variants have been associated with recessive inheritance, and often these individuals have more severe clinical presentations. Additionally, pathogenic variants in X-linked genes have been identified in both affected males and females, possibly due to a lack of X-chromosome inactivation skewing. Collectively, exome sequencing has resulted in a molecular diagnosis for many individuals with DEE, but this still leaves many cases unsolved. Multiple factors contribute to the missing etiology, including nonexonic variants, mosaicism, epigenetics, and oligogenic inheritance. Here, we focus on the first 2 factors. We discuss the promises and challenges of genome sequencing, which allows for a more comprehensive analysis of the genome, including interpretation of structural and noncoding variants and also yields a high number of de novo variants for interpretation. We also consider the contribution of genetic mosaicism, both what it means for a molecular diagnosis in mosaic individuals and the important implications for genetic counseling.
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Affiliation(s)
- Hannah C Happ
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Gemma L Carvill
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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57
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Chi W, Iyengar ASR, Albersen M, Bosma M, Verhoeven-Duif NM, Wu CF, Zhuang X. Pyridox (am) ine 5'-phosphate oxidase deficiency induces seizures in Drosophila melanogaster. Hum Mol Genet 2020; 28:3126-3136. [PMID: 31261385 DOI: 10.1093/hmg/ddz143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022] Open
Abstract
Pyridox (am) ine 5'-phosphate oxidase (PNPO) is a rate-limiting enzyme in converting dietary vitamin B6 (VB6) to pyridoxal 5'-phosphate (PLP), the biologically active form of VB6 and involved in the synthesis of neurotransmitters including γ-aminobutyric acid (GABA), dopamine, and serotonin. In humans, PNPO mutations have been increasingly identified in neonatal epileptic encephalopathy and more recently also in early-onset epilepsy. Till now, little is known about the neurobiological mechanisms underlying PNPO-deficiency-induced seizures due to the lack of animal models. Previously, we identified a c.95 C>A missense mutation in sugarlethal (sgll)-the Drosophila homolog of human PNPO (hPNPO)-and found mutant (sgll95) flies exhibiting a lethal phenotype on a diet devoid of VB6. Here, we report the establishment of both sgll95 and ubiquitous sgll knockdown (KD) flies as valid animal models of PNPO-deficiency-induced epilepsy. Both sgll95 and sgll KD flies exhibit spontaneous seizures before they die. Electrophysiological recordings reveal that seizures caused by PNPO deficiency have characteristics similar to that in flies treated with the GABA antagonist picrotoxin. Both seizures and lethality are associated with low PLP levels and can be rescued by ubiquitous expression of wild-type sgll or hPNPO, suggesting the functional conservation of the PNPO enzyme between humans and flies. Results from cell type-specific sgll KD further demonstrate that PNPO in the brain is necessary for seizure prevention and survival. Our establishment of the first animal model of PNPO deficiency will lead to better understanding of VB6 biology, the PNPO gene and its mutations discovered in patients, and can be a cost-effective system to test therapeutic strategies.
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Affiliation(s)
- Wanhao Chi
- Committee on Genetics, Genomics and Systems Biology.,Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Atulya S R Iyengar
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Monique Albersen
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Marjolein Bosma
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Nanda M Verhoeven-Duif
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Chun-Fang Wu
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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CRISPR/Cas9-mediated mutation of asparagine-linked glycosylation 13 transcript variant 1 causes epilepsy in mice. JOURNAL OF BIO-X RESEARCH 2020. [DOI: 10.1097/jbr.0000000000000059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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59
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Krey I, Krois-Neudenberger J, Hentschel J, Syrbe S, Polster T, Hanker B, Fiedler B, Kurlemann G, Lemke JR. Genotype-phenotype correlation on 45 individuals with West syndrome. Eur J Paediatr Neurol 2020; 25:134-138. [PMID: 31791873 DOI: 10.1016/j.ejpn.2019.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/22/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022]
Abstract
West syndrome is an epilepsy syndrome characterized by repetitive epileptic spasms (ES) and hypsarrhythmia, typically leading to developmental delay/intellectual disability (DD/ID). It is considered a classic epileptic encephalopathy (EE). We designed a diagnostic sequencing panel targeting 131 genes associated with epilepsy and/or EE and screened a cohort of 45 individuals with clinical diagnosis of West syndrome. We identified disease-causing single nucleotide variants in 11 out of 45 individuals affecting genes commonly associated with West syndrome (such as CDKL5, ARX) but also in genes predominantly linked to other epileptic disorders (such as DEPDC5, SCN1A, WDR45, AARS). Panel analysis revealed copy number variants in two additional cases, comprising a 6,7 Mb Duplication on chromosome 2 including SCN2A and SCN3A and a supernumerary marker chromosome 15 leading to an overall diagnostic yield of 29% (13/45). In our cohort, individuals with a disease-causing variant had significantly more severe phenotypes with respect to DD/ID, therapy resistant epilepsy and cerebral atrophy compared to genetically unclarified cases. In addition to investigating the genotypic spectrum of West syndrome, we compared the phenotypic spectrum of clarified versus unclarified cases. Our study illustrates that West syndrome is an electroclinical syndrome caused by various genetic disorders. Individuals without detectable genetic cause might have less encephalopathy leading to a less severe course.
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Affiliation(s)
- Ilona Krey
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.
| | - Janna Krois-Neudenberger
- Department of General Pediatrics, Division of Neuropediatrics, University Hospital Muenster, Germany.
| | - Julia Hentschel
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.
| | - Steffen Syrbe
- Division of Child Neurology and Metabolic Medicine, Center for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, Germany.
| | - Tilman Polster
- Bethel Epilepsy Center, Mara Hospital, Bielefeld, Germany.
| | - Britta Hanker
- Institute of Human Genetics, University of Lübeck, Lübeck, Germany.
| | - Barbara Fiedler
- Department of General Pediatrics, Division of Neuropediatrics, University Hospital Muenster, Germany.
| | | | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.
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Zhu B, Mak JCH, Morris AP, Marson AG, Barclay JW, Sills GJ, Morgan A. Functional analysis of epilepsy-associated variants in STXBP1/Munc18-1 using humanized Caenorhabditis elegans. Epilepsia 2020; 61:810-821. [PMID: 32112430 PMCID: PMC8614121 DOI: 10.1111/epi.16464] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Genetic variants in STXBP1, which encodes the conserved exocytosis protein Munc18-1, are associated with a variety of infantile epilepsy syndromes. We aimed to develop an in vivo Caenorhabditis elegans model that could be used to test the pathogenicity of such variants in a cost-effective manner. METHODS The CRISPR/Cas9 method was used to introduce a null mutation into the unc-18 gene (the C. elegans orthologue of STXBP1), thereby creating a paralyzed worm strain. We subsequently rescued this strain with transgenes encoding the human STXBP1/Munc18-1 protein (wild-type and eight different epilepsy-associated missense variants). The resulting humanized worm strains were then analyzed via behavioral, electrophysiological, and biochemical approaches. RESULTS Transgenic expression of wild-type human STXBP1 protein fully rescued locomotion in both solid and liquid media to the same level as the standard wild-type worm strain, Bristol N2. Six variant strains (E59K, V84D, C180Y, R292H, L341P, R551C) exhibited impaired locomotion, whereas two (P335L, R406H) were no different from worms expressing wild-type STXBP1. Electrophysiological recordings revealed that all eight variant strains displayed less frequent and more irregular pharyngeal pumping in comparison to wild-type STXBP1-expressing strains. Four strains (V84D, C180Y, R292H, P335L) exhibited pentylenetetrazol-induced convulsions in an acute assay of seizure-like activity, in contrast to worms expressing wild-type STXBP1. No differences were seen between wild-type and variant STXBP1 strains in terms of mRNA abundance. However, STXBP1 protein levels were reduced to 20%-30% of wild-type in all variants, suggesting that the mutations result in STXBP1 protein instability. SIGNIFICANCE The approach described here is a cost-effective in vivo method for establishing the pathogenicity of genetic variants in STXBP1 and potentially other conserved neuronal proteins. Furthermore, the humanized strains we created could potentially be used in the future for high-throughput drug screens to identify novel therapeutics.
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Affiliation(s)
- Bangfu Zhu
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Jennifer C H Mak
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.,Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Andrew P Morris
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.,Department of Biostatistics, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.,Division of Musculoskeletal and Dermatological Sciences, University of Manchester, Manchester, UK
| | - Anthony G Marson
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Jeff W Barclay
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Graeme J Sills
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.,School of Life Sciences, University of Glasgow, Glasgow, UK
| | - Alan Morgan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Rochtus A, Olson HE, Smith L, Keith LG, El Achkar C, Taylor A, Mahida S, Park M, Kelly M, Shain C, Rockowitz S, Sheidley BR, Poduri A. Genetic diagnoses in epilepsy: The impact of dynamic exome analysis in a pediatric cohort. Epilepsia 2020; 61:249-258. [PMID: 31957018 PMCID: PMC7404709 DOI: 10.1111/epi.16427] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 01/02/2023]
Abstract
OBJECTIVE We evaluated the yield of systematic analysis and/or reanalysis of whole exome sequencing (WES) data from a cohort of well-phenotyped pediatric patients with epilepsy and suspected but previously undetermined genetic etiology. METHODS We identified and phenotyped 125 participants with pediatric epilepsy. Etiology was unexplained at the time of enrollment despite clinical testing, which included chromosomal microarray (57 patients), epilepsy gene panel (n = 48), both (n = 28), or WES (n = 8). Clinical epilepsy diagnoses included developmental and epileptic encephalopathy (DEE), febrile infection-related epilepsy syndrome, Rasmussen encephalitis, and other focal and generalized epilepsies. We analyzed WES data and compared the yield in participants with and without prior clinical genetic testing. RESULTS Overall, we identified pathogenic or likely pathogenic variants in 40% (50/125) of our study participants. Nine patients with DEE had genetic variants in recently published genes that had not been recognized as epilepsy-related at the time of clinical testing (FGF12, GABBR1, GABBR2, ITPA, KAT6A, PTPN23, RHOBTB2, SATB2), and eight patients had genetic variants in candidate epilepsy genes (CAMTA1, FAT3, GABRA6, HUWE1, PTCHD1). Ninety participants had concomitant or subsequent clinical genetic testing, which was ultimately explanatory for 26% (23/90). Of the 67 participants whose molecular diagnoses were "unsolved" through clinical genetic testing, we identified pathogenic or likely pathogenic variants in 17 (25%). SIGNIFICANCE Our data argue for early consideration of WES with iterative reanalysis for patients with epilepsy, particularly those with DEE or epilepsy with intellectual disability. Rigorous analysis of WES data of well-phenotyped patients with epilepsy leads to a broader understanding of gene-specific phenotypic spectra as well as candidate disease gene identification. We illustrate the dynamic nature of genetic diagnosis over time, with analysis and in some cases reanalysis of exome data leading to the identification of disease-associated variants among participants with previously nondiagnostic results from a variety of clinical testing strategies.
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Affiliation(s)
- Anne Rochtus
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, University of Leuven, Leuven, Belgium
| | - Heather E. Olson
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Lacey Smith
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Louisa G. Keith
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Christelle El Achkar
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Alan Taylor
- Department of Genomics, Al Jalila Children’s Specialty Hospital, Dubai, UAE
| | - Sonal Mahida
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Meredith Park
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - McKenna Kelly
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Catherine Shain
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Shira Rockowitz
- Information Services Department, Boston Children’s Hospital, Boston, MA, USA
| | - Beth Rosen Sheidley
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
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Infantile Spasms: An Update on Pre-Clinical Models and EEG Mechanisms. CHILDREN-BASEL 2020; 7:children7010005. [PMID: 31935804 PMCID: PMC7023485 DOI: 10.3390/children7010005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/06/2019] [Accepted: 12/23/2019] [Indexed: 12/18/2022]
Abstract
Infantile spasms (IS) is an epileptic encephalopathy with unique clinical and electrographic features, which affects children in the middle of the first year of life. The pathophysiology of IS remains incompletely understood, despite the heterogeneity of IS etiologies, more than 200 of which are known. In particular, the neurobiological basis of why multiple etiologies converge to a relatively similar clinical presentation has defied explanation. Treatment options for this form of epilepsy, which has been described as “catastrophic” because of the poor cognitive, developmental, and epileptic prognosis, are limited and not fully effective. Until the pathophysiology of IS is better clarified, novel treatments will not be forthcoming, and preclinical (animal) models are essential for advancing this knowledge. Here, we review preclinical IS models, update information regarding already existing models, describe some novel models, and discuss exciting new data that promises to advance understanding of the cellular mechanisms underlying the specific EEG changes seen in IS—interictal hypsarrhythmia and ictal electrodecrement.
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Symonds JD, McTague A. Epilepsy and developmental disorders: Next generation sequencing in the clinic. Eur J Paediatr Neurol 2020; 24:15-23. [PMID: 31882278 DOI: 10.1016/j.ejpn.2019.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND The advent of Next Generation Sequencing (NGS) has led to a redefining of the genetic landscape of the epilepsies. Hundreds of single gene epilepsies have been described. Genes associated with epilepsy involve diverse processes. Now a substantial proportion of individuals with epilepsy can receive a high definition molecular genetic diagnosis. METHODS In this review we update the current genetic landscape of the epilepsies and categorise the major functional groupings of epilepsy-associated genes. We describe currently available genetic testing approaches. We perform a literature review of NGS studies and review the factors which determine yield in cohorts undergoing testing. We identify factors associated with positive genetic diagnosis and consider the utility of genetic testing in terms of treatment selection as well as more qualitative aspects of care. FINDINGS Epilepsy-associated genes can be grouped into five broad functional categories: ion transport; cell growth and differentiation; regulation of synaptic processes; transport and metabolism of small molecules within and between cells; and regulation of gene transcription and translation. Early onset of seizures, drug-resistance, and developmental comorbidity are associated with higher diagnostic yield. The most commonly implicated genes in NGS studies to date, in order, are SCN1A, KCNQ2, CDKL5, SCN2A, and STXBP1. In unselected infantile cohorts PRRT2, a gene associated with self-limited epilepsy, is frequently implicated. Genetic diagnosis provides utility in terms of treatment choice closing the diagnostic odyssey, avoiding unnecessary further testing, and informing future reproductive decisions. CONCLUSIONS Genetic testing has become a first line test in epilepsy. As techniques improve and understanding advances, its utility is set to increase. Genetic diagnosis, particularly in early onset developmental and epileptic encephalopathies, influences treatment choice in a significant proportion of patients. The realistic prospect of gene therapy is a cause for optimism.
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Affiliation(s)
- Joseph D Symonds
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow, G51 4TF, UK; Medical Veterinary and Life Sciences, University of Glasgow, G12 8QQ, UK.
| | - Amy McTague
- Institute of Child Health, University Collge London, 30 Guilford St, Holborn, London WC1N 1EH, UK
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Jiang X, Raju PK, D'Avanzo N, Lachance M, Pepin J, Dubeau F, Mitchell WG, Bello-Espinosa LE, Pierson TM, Minassian BA, Lacaille JC, Rossignol E. Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome. Epilepsia 2019; 60:1881-1894. [PMID: 31468518 DOI: 10.1111/epi.16316] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. METHODS We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV 2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. RESULTS We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. SIGNIFICANCE Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.
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Affiliation(s)
- Xiao Jiang
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
| | - Praveen K Raju
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
| | - Nazzareno D'Avanzo
- Department of Pharmacology and Physiology, University of Montréal, Montréal, Canada
| | - Mathieu Lachance
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada
| | - Julie Pepin
- Department of Neurosciences, University of Montréal, Montreal, Canada
| | - François Dubeau
- Department of Neurosciences, The Montreal Neurological Institute, McGill University, Montréal, Canada
| | - Wendy G Mitchell
- Neurology Division, Children's Hospital Los Angeles & Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | | | - Tyler M Pierson
- Departments of Pediatrics and Neurology, The Board of Governors Regenerative Medicine Institute, Los Angeles, CA, USA
| | | | | | - Elsa Rossignol
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
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Muir AM, Myers CT, Nguyen NT, Saykally J, Craiu D, De Jonghe P, Helbig I, Hoffman-Zacharska D, Guerrini R, Lehesjoki AE, Marini C, Møller RS, Serratosa J, Štěrbová K, Striano P, von Spiczak S, Weckhuysen S, Mefford HC. Genetic heterogeneity in infantile spasms. Epilepsy Res 2019; 156:106181. [PMID: 31394400 DOI: 10.1016/j.eplepsyres.2019.106181] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/27/2019] [Indexed: 11/25/2022]
Abstract
Infantile spasms (IS) is a developmental and epileptic encephalopathy with heterogeneous etiologies including many genetic causes. Genetic studies have identified pathogenic variants in over 30 genes as causes of IS. Many of these genetic causes are extremely rare, with only one reported incidence in an individual with IS. To better understand the genetic landscape of IS, we used targeted sequencing to screen 42 candidate IS genes and 53 established developmental and epileptic encephalopathy genes in 92 individual with IS. We identified a genetic diagnosis for 7.6% of our cohort, including pathogenic variants in KCNB1 (n = 2), GNAO1 (n = 1), STXBP1 (n = 1), SLC35A2 (n = 1), TBL1XR1 (n = 1), and KIF1A (n = 1). Our data emphasize the genetic heterogeneity of IS and will inform the diagnosis and management of individuals with this devastating disorder.
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Affiliation(s)
- Alison M Muir
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Candace T Myers
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Nancy T Nguyen
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Julia Saykally
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Dana Craiu
- Department of Clinical Neurosciences and Pediatric Neurology Clinic, "Carol Davila" University of Medicine, Al. Obregia Hospital, Bucharest 050474, Romania; Pediatric Neurology Clinic Alexandru Obregia Hospital Bucharest Romania
| | - Peter De Jonghe
- Neurogenetics Group, Center for Molecular Neurology, VIB, University of Antwerp, Antwerp 2610, Belgium; Institute Born Bunge, University of Antwerp, Antwerp 2610, Belgium; Department of Neurology, Antwerp University Hospital, Antwerp 2650, Belgium
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neuropediatrics, Christian-Albrechts-University Kiel and University Hospital Schleswig-Holstein, Campus Kiel 24105, Germany
| | - Dorota Hoffman-Zacharska
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland; Institute of Genetics and Biotechnology, Warsaw University, Warsaw, Poland
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, A. Meyer Children's Hospital, University of Florence, Florence 50139, Italy
| | - Anna-Elina Lehesjoki
- Folkhälsan Research Center and Medical Faculty, University of Helsinki, Helsinki 00290, Finland
| | - Carla Marini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, A. Meyer Children's Hospital, University of Florence, Florence 50139, Italy
| | - Rikke S Møller
- Danish Epilepsy Centre, Dianalund 4293, Denmark; Institute for Regional Health research, University of Southern Denmark, Odense 5230, Denmark
| | - Jose Serratosa
- Department of Neurology, Neurology Lab and Epilepsy Unit, IIS-Fundación Jiménez Díaz UAM and CIBERER, Madrid 28040, Spain
| | - Katalin Štěrbová
- Child Neurology Department, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague 150 06, Czech Republic
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "G. Gaslini", Genova 16147, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova 16132, Italy
| | - Sarah von Spiczak
- Department of Neuropediatrics, Christian-Albrechts-University Kiel and University Hospital Schleswig-Holstein, Campus Kiel 24105, Germany; Northern German Epilepsy Center for Children and Adolescents, Schwentinental-Raisdorf, 24223, Germany
| | - Sarah Weckhuysen
- Neurogenetics Group, Center for Molecular Neurology, VIB, University of Antwerp, Antwerp 2610, Belgium; Institute Born Bunge, University of Antwerp, Antwerp 2610, Belgium; Department of Neurology, Antwerp University Hospital, Antwerp 2650, Belgium
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA.
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ALG13 Deficiency Associated with Increased Seizure Susceptibility and Severity. Neuroscience 2019; 409:204-221. [DOI: 10.1016/j.neuroscience.2019.03.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 01/31/2023]
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Abstract
Epilepsy in infants and children is one of the most common and devastating neurological disorders. In the past, we had a limited understanding of the causes of epilepsy in pediatric patients, so we treated pediatric epilepsy according to seizure type. Now with new tools and tests, we are entering the age of precision medicine in pediatric epilepsy. In this review, we use the new etiological classification system proposed by the International League Against Epilepsy to review the advances in the diagnosis of pediatric epilepsy, describe new tools to identify seizure foci for epilepsy surgery, and define treatable epilepsy syndromes.
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Affiliation(s)
- Priya Sharma
- Department of Neurology, University of North Carolina School of Medicine, Physicians Office Building, Chapel Hill, NC, 27599-7025, USA
| | - Ammar Hussain
- Department of Neurology, University of North Carolina School of Medicine, Physicians Office Building, Chapel Hill, NC, 27599-7025, USA
| | - Robert Greenwood
- Department of Neurology & Pediatrics, University of North Carolina School of Medicine, 2141 Physicians Office Building, Chapel Hill, NC, 27599-7025, USA
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68
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Sánchez Fernández I, Loddenkemper T, Gaínza-Lein M, Sheidley BR, Poduri A. Diagnostic yield of genetic tests in epilepsy: A meta-analysis and cost-effectiveness study. Neurology 2019; 92:e418-e428. [PMID: 30610098 PMCID: PMC6369901 DOI: 10.1212/wnl.0000000000006850] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 08/30/2018] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE To compare the cost-effectiveness of genetic testing strategies in patients with epilepsy of unknown etiology. METHODS This meta-analysis and cost-effectiveness study compared strategies involving 3 genetic tests: chromosomal microarray (CMA), epilepsy panel (EP) with deletion/duplication testing, and whole-exome sequencing (WES) in a cost-effectiveness model, using "no genetic testing" as a point of comparison. RESULTS Twenty studies provided information on the diagnostic yield of CMA (8 studies), EP (9 studies), and WES (6 studies). The diagnostic yield was highest for WES: 0.45 (95% confidence interval [CI]: 0.33-0.57) (0.32 [95% CI: 0.22-0.44] adjusting for potential publication bias), followed by EP: 0.23 (95% CI: 0.18-0.29), and CMA: 0.08 (95% CI: 0.06-0.12). The most cost-effective test was WES with an incremental cost-effectiveness ratio (ICER) of $15,000/diagnosis. However, after adjusting for potential publication bias, the most cost-effective test was EP (ICER: $15,848/diagnosis) followed by WES (ICER: $34,500/diagnosis). Among combination strategies, the most cost-effective strategy was WES, then if nondiagnostic, EP, then if nondiagnostic, CMA (ICER: $15,336/diagnosis), although adjusting for potential publication bias, the most cost-effective strategy was EP ± CMA ± WES (ICER: $18,385/diagnosis). While the cost-effectiveness of individual tests and testing strategies overlapped, CMA was consistently less cost-effective than WES and EP. CONCLUSION WES and EP are the most cost-effective genetic tests for epilepsy. Our analyses support, for a broad population of patients with unexplained epilepsy, starting with these tests. Although less expensive, CMA has lower yield, and its use as the first-tier test is thus not supported from a cost-effectiveness perspective.
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Affiliation(s)
- Iván Sánchez Fernández
- From the Epilepsy Genetics Program (B.R.S., A.P.), Division of Epilepsy and Clinical Neurophysiology (I.S.F., T.L., M.G.-L., B.R.S., A.P.), Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Child Neurology (I.S.F.), Hospital Sant Joan de Déu, Universidad de Barcelona, Spain; and Facultad de Medicina (M.G.-L.), Universidad Austral de Chile, Valdivia
| | - Tobias Loddenkemper
- From the Epilepsy Genetics Program (B.R.S., A.P.), Division of Epilepsy and Clinical Neurophysiology (I.S.F., T.L., M.G.-L., B.R.S., A.P.), Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Child Neurology (I.S.F.), Hospital Sant Joan de Déu, Universidad de Barcelona, Spain; and Facultad de Medicina (M.G.-L.), Universidad Austral de Chile, Valdivia
| | - Marina Gaínza-Lein
- From the Epilepsy Genetics Program (B.R.S., A.P.), Division of Epilepsy and Clinical Neurophysiology (I.S.F., T.L., M.G.-L., B.R.S., A.P.), Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Child Neurology (I.S.F.), Hospital Sant Joan de Déu, Universidad de Barcelona, Spain; and Facultad de Medicina (M.G.-L.), Universidad Austral de Chile, Valdivia
| | - Beth Rosen Sheidley
- From the Epilepsy Genetics Program (B.R.S., A.P.), Division of Epilepsy and Clinical Neurophysiology (I.S.F., T.L., M.G.-L., B.R.S., A.P.), Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Child Neurology (I.S.F.), Hospital Sant Joan de Déu, Universidad de Barcelona, Spain; and Facultad de Medicina (M.G.-L.), Universidad Austral de Chile, Valdivia
| | - Annapurna Poduri
- From the Epilepsy Genetics Program (B.R.S., A.P.), Division of Epilepsy and Clinical Neurophysiology (I.S.F., T.L., M.G.-L., B.R.S., A.P.), Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Child Neurology (I.S.F.), Hospital Sant Joan de Déu, Universidad de Barcelona, Spain; and Facultad de Medicina (M.G.-L.), Universidad Austral de Chile, Valdivia.
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69
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Mori T, Kasem EA, Suzuki-Kouyama E, Cao X, Li X, Kurihara T, Uemura T, Yanagawa T, Tabuchi K. Deficiency of calcium/calmodulin-dependent serine protein kinase disrupts the excitatory-inhibitory balance of synapses by down-regulating GluN2B. Mol Psychiatry 2019; 24:1079-1092. [PMID: 30610199 PMCID: PMC6756202 DOI: 10.1038/s41380-018-0338-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 11/27/2018] [Accepted: 12/10/2018] [Indexed: 11/24/2022]
Abstract
Calcium/calmodulin-dependent serine protein kinase (CASK) is a membrane-associated guanylate kinase (MAGUK) protein that is associated with neurodevelopmental disorders. CASK is thought to have both pre- and postsynaptic functions, but the mechanism and consequences of its functions in the brain have yet to be elucidated, because homozygous CASK-knockout (CASK-KO) mice die before brain maturation. Taking advantage of the X-chromosome inactivation (XCI) mechanism, here we examined the synaptic functions of CASK-KO neurons in acute brain slices of heterozygous CASK-KO female mice. We also analyzed CASK-knockdown (KD) neurons in acute brain slices generated by in utero electroporation. Both CASK-KO and CASK-KD neurons showed a disruption of the excitatory and inhibitory (E/I) balance. We further found that the expression level of the N-methyl-D-aspartate receptor subunit GluN2B was decreased in CASK-KD neurons and that overexpressing GluN2B rescued the disrupted E/I balance in CASK-KD neurons. These results suggest that the down-regulation of GluN2B may be involved in the mechanism of the disruption of synaptic E/I balance in CASK-deficient neurons.
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Affiliation(s)
- Takuma Mori
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan
| | - Enas A. Kasem
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan ,0000 0004 0578 3577grid.411978.2Department of Zoology, Faculty of Science, Kafr Elsheikh University, Kafr Elsheihk, 33511 Egypt
| | - Emi Suzuki-Kouyama
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan
| | - Xueshan Cao
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan
| | - Xue Li
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan
| | - Taiga Kurihara
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan
| | - Takeshi Uemura
- 0000 0001 1507 4692grid.263518.bDepartment of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621 Japan ,0000 0001 1507 4692grid.263518.bInstitute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, 390-8621 Japan ,0000 0004 1754 9200grid.419082.6CREST, JST, Saitama, 332-0012 Japan
| | - Toru Yanagawa
- 0000 0001 2369 4728grid.20515.33Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki, 305-8575 Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, 390-8621, Japan. .,Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, 390-8621, Japan. .,PRESTO, JST, Saitama, 332-0012, Japan.
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70
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LaConte LEW, Chavan V, DeLuca S, Rubin K, Malc J, Berry S, Gail Summers C, Mukherjee K. An N-terminal heterozygous missense CASK mutation is associated with microcephaly and bilateral retinal dystrophy plus optic nerve atrophy. Am J Med Genet A 2018; 179:94-103. [PMID: 30549415 DOI: 10.1002/ajmg.a.60687] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/26/2018] [Accepted: 10/17/2018] [Indexed: 11/08/2022]
Abstract
Heterozygous loss-of-function mutations in the X-linked gene CASK are associated with mental retardation and microcephaly with pontine and cerebellar hypoplasia (MICPCH) and ophthalmological disorders including optic nerve atrophy (ONA) and optic nerve hypoplasia (ONH). Recently, we have demonstrated that CASK(+/-) mice display ONH with 100% penetrance but exhibit no change in retinal lamination or structure. It is not clear if CASK loss-of-function predominantly affects retinal ganglion cells, or if other retinal cells like photoreceptors are also involved. Here, we report a heterozygous missense mutation in the N-terminal calcium/calmodulin-dependent kinase (CaMK) domain of the CASK protein in which a highly conserved leucine is mutated to the cyclic amino acid proline. In silico analysis suggests that the mutation may produce destabilizing structural changes. Experimentally, we observe pronounced misfolding and insolubility of the CASKL209P protein. Interestingly, the remaining soluble mutant protein fails to interact with Mint1, which specifically binds to CASK's CaMK domain, suggesting a mechanism for the phenotypes observed with the CASKL209P mutation. In addition to microcephaly, cerebellar hypoplasia and delayed development, the subject with the L209P mutation also presented with bilateral retinal dystrophy and ONA. Electroretinography indicated that rod photoreceptors are the most prominently affected cells. Our data suggest that the CASK interactions mediated by the CaMK domain may play a crucial role in retinal function, and thus, in addition to ONH, individuals with mutations in the CASK gene may exhibit other retinal disorders, depending on the nature of mutation.
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Affiliation(s)
| | - Vrushali Chavan
- Virginia Tech Carilion Research Institute, Roanoke, Virginia
| | | | - Karol Rubin
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, Minnesota
| | - Jessica Malc
- Virginia Tech Carilion Research Institute, Roanoke, Virginia
| | - Susan Berry
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, Minnesota
| | - C Gail Summers
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota
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Eid L, Raju PK, Rossignol E. PHACTRing in actin: actin deregulation in genetic epilepsies. Brain 2018; 141:3084-3088. [PMID: 30364981 DOI: 10.1093/brain/awy272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lara Eid
- CHU Sainte-Justine Research Center, Montreal, Canada.,Department of Neurosciences, University of Montreal, Montreal, Canada
| | - Praveen K Raju
- CHU Sainte-Justine Research Center, Montreal, Canada.,Department of Neurosciences, University of Montreal, Montreal, Canada
| | - Elsa Rossignol
- CHU Sainte-Justine Research Center, Montreal, Canada.,Department of Neurosciences, University of Montreal, Montreal, Canada.,Department of Pediatrics, University of Montreal, Montreal, Canada
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72
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Bozarth X, Foss K, Mefford HC. A de novo in-frame deletion of CASK
gene causes early onset infantile spasms and supratentorial cerebral malformation in a female patient. Am J Med Genet A 2018; 176:2425-2429. [DOI: 10.1002/ajmg.a.40429] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/06/2018] [Accepted: 06/10/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Xiuhua Bozarth
- Department of Neurology; Seattle Children's Hospital, University of Washington; Seattle Washington
| | - Kimberly Foss
- Department of Genetics; Seattle Children's Hospital; Seattle Washington
| | - Heather C. Mefford
- Division of Genetic Medicine, Department of Pediatrics; University of Washington; Seattle Washington
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Li T, Cheng M, Wang J, Hong S, Li M, Liao S, Xie L, Jiang L. De novo mutations of STXBP1 in Chinese children with early onset epileptic encephalopathy. GENES BRAIN AND BEHAVIOR 2018; 17:e12492. [PMID: 29896790 DOI: 10.1111/gbb.12492] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/04/2018] [Accepted: 06/11/2018] [Indexed: 11/30/2022]
Abstract
To detect syntaxin-binding protein 1 (STXBP1) mutations in Chinese patients with early onset epileptic encephalopathy (EOEE) of unknown etiology. Targeted next-generation sequencing was used to identify STXBP1 mutations in 143 Chinese patients with EOEE of unknown etiology. A filtering process was applied to prioritize rare variants of potential functional significance. Then Sanger sequencing was employed to validate the parental origin of the variants. Detailed clinical and genetic data were collected for 9 STXBP1-positive patients. Eight de novo heterozygous STXBP1 mutations were identified in 9 patients; 5 were novel mutations (c.1155delC, c.1030-1G>A, c.217G>C, c.268G>C, c.1480_1481 insT) and 3 were previously reported (c.1216C> T, c.1217G>A [2 cases], c.875G>A). Two patients had Ohtahara syndrome and 1 had West syndrome at onset, whereas the other 6 presented with EOEE that did not fit a specific recognized epilepsy syndrome. Six of these patients later evolved to West syndrome. All but 2 cases were prescribed more than 2 antiepileptic drugs (AEDs) plus other regimens. Four subjects showed good responses to levetiracetam (LEV) alone or in combination with other AEDs, and one case (1/3) achieved complete freedom from seizures with a ketogenic diet (KD). All patients exhibited severe to profound global developmental delay. Five novel heterozygous de novo STXBP1 mutations were discovered in patients with EOEE from China. STXBP1 mutational analysis should be performed in cases of EOEE of unknown etiology. LEV as monotherapy or adjunctive therapy with other regimens, as well as KD should be considered for management of this patient group.
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Affiliation(s)
- T Li
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - M Cheng
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - J Wang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - S Hong
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - M Li
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - S Liao
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - L Xie
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - L Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
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74
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Calderón Romero M, Arce Portillo E, López Lobato M, Muñoz Cabello B, Blanco Martínez B, Madruga Garrido M, Alonso Luego O. Síndrome de West criptogénico: perfil clínico, respuesta al tratamiento y factores pronósticos. An Pediatr (Barc) 2018; 89:176-182. [DOI: 10.1016/j.anpedi.2017.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/22/2017] [Accepted: 10/25/2017] [Indexed: 10/18/2022] Open
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75
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Calderón Romero M, Arce Portillo E, López Lobato M, Muñoz Cabello B, Blanco Martínez B, Madruga Garrido M, Alonso Luego O. Cryptogenic West syndrome: Clinical profile, response to treatment and prognostic factors. ANALES DE PEDIATRÍA (ENGLISH EDITION) 2018. [DOI: 10.1016/j.anpede.2017.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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76
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Myers KA, Johnstone DL, Dyment DA. Epilepsy genetics: Current knowledge, applications, and future directions. Clin Genet 2018; 95:95-111. [PMID: 29992546 DOI: 10.1111/cge.13414] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 12/12/2022]
Abstract
The rapid pace of disease gene discovery has resulted in tremendous advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, and genomes are now available and have led to higher diagnostic rates and insights into the underlying disease processes. As such, the contribution to the care of patients by medical geneticists, neurogeneticists and genetic counselors are significant; the dysmorphic examination, the necessary pre- and post-test counseling, the selection of the appropriate next-generation sequencing-based test(s), and the interpretation of sequencing results require a care provider to have a comprehensive working knowledge of the strengths and limitations of the available testing technologies. As the underlying mechanisms of the encephalopathies and epilepsies are better understood, there may be opportunities for the development of novel therapies based on an individual's own specific genotype. Drug screening with in vitro and in vivo models of epilepsy can potentially facilitate new treatment strategies. The future of epilepsy genetics will also probably include other-omic approaches such as transcriptomes, metabolomes, and the expanded use of whole genome sequencing to further improve our understanding of epilepsy and provide better care for those with the disease.
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Affiliation(s)
- K A Myers
- Department of Pediatrics, University of McGill, Montreal, Canada.,Research Institute of the McGill University Health Centre, Montreal, Canada
| | - D L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
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77
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Kothur K, Holman K, Farnsworth E, Ho G, Lorentzos M, Troedson C, Gupta S, Webster R, Procopis PG, Menezes MP, Antony J, Ardern-Holmes S, Dale RC, Christodoulou J, Gill D, Bennetts B. Diagnostic yield of targeted massively parallel sequencing in children with epileptic encephalopathy. Seizure 2018; 59:132-140. [DOI: 10.1016/j.seizure.2018.05.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 02/20/2018] [Accepted: 05/08/2018] [Indexed: 12/28/2022] Open
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78
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Abstract
West syndrome (WS) is an early life epileptic encephalopathy associated with infantile spasms, interictal electroencephalography (EEG) abnormalities including high amplitude, disorganized background with multifocal epileptic spikes (hypsarrhythmia), and often neurodevelopmental impairments. Approximately 64% of the patients have structural, metabolic, genetic, or infectious etiologies and, in the rest, the etiology is unknown. Here we review the contribution of etiologies due to various metabolic disorders in the pathology of WS. These may include metabolic errors in organic molecules involved in amino acid and glucose metabolism, fatty acid oxidation, metal metabolism, pyridoxine deficiency or dependency, or acidurias in organelles such as mitochondria and lysosomes. We discuss the biochemical, clinical, and EEG features of these disorders as well as the evidence of how they may be implicated in the pathogenesis and treatment of WS. The early recognition of these etiologies in some cases may permit early interventions that may improve the course of the disease.
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Affiliation(s)
- Seda Salar
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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79
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Oates S, Tang S, Rosch R, Lear R, Hughes EF, Williams RE, Larsen LHG, Hao Q, Dahl HA, Møller RS, Pal DK. Incorporating epilepsy genetics into clinical practice: a 360°evaluation. NPJ Genom Med 2018; 3:13. [PMID: 29760947 PMCID: PMC5945675 DOI: 10.1038/s41525-018-0052-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 04/04/2018] [Accepted: 04/09/2018] [Indexed: 01/13/2023] Open
Abstract
We evaluated a new epilepsy genetic diagnostic and counseling service covering a UK population of 3.5 million. We calculated diagnostic yield, estimated clinical impact, and surveyed referring clinicians and families. We costed alternative investigational pathways for neonatal onset epilepsy. Patients with epilepsy of unknown aetiology onset < 2 years; treatment resistant epilepsy; or familial epilepsy were referred for counseling and testing. We developed NGS panels, performing clinical interpretation with a multidisciplinary team. We held an educational workshop for paediatricians and nurses. We sent questionnaires to referring paediatricians and families. We analysed investigation costs for 16 neonatal epilepsy patients. Of 96 patients, a genetic diagnosis was made in 34% of patients with seizure onset < 2 years, and 4% > 2 years, with turnaround time of 21 days. Pathogenic variants were seen in SCN8A, SCN2A, SCN1A, KCNQ2, HNRNPU, GRIN2A, SYNGAP1, STXBP1, STX1B, CDKL5, CHRNA4, PCDH19 and PIGT. Clinician prediction was poor. Clinicians and families rated the service highly. In neonates, the cost of investigations could be reduced from £9362 to £2838 by performing gene panel earlier and the median diagnostic delay of 3.43 years reduced to 21 days. Panel testing for epilepsy has a high yield among children with onset < 2 years, and an appreciable clinical and financial impact. Parallel gene testing supersedes single gene testing in most early onset cases that do not show a clear genotype-phenotype correlation. Clinical interpretation of laboratory results, and in-depth discussion of implications for patients and their families, necessitate multidisciplinary input and skilled genetic counseling. Screening for epilepsy-related gene variants can lead to effective, personalized treatment plans while reducing costs. UK and Danish scientists, led by Deb Pal, King’s College London, evaluated a new service within the UK that searches for genetic variants in patients that cause epilepsy. The authors assessed the impact of next-generation gene panel tests, as well as the necessary resources to make such a service effective. Genetic testing was most effective in patients with seizure onset under 2 years old (21% diagnosed) and yield even higher in neonatal-onset epilepsy (63% diagnosed). For many patients with pathogenic variants, the diagnoses allowed for recommendations on treatment or enrolment in clinical trials. The researchers found that diagnostic delay and financial burden in neonatal epilepsy could be drastically reduced with gene panel testing. The scheme was highly rated by users and patients alike.
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Affiliation(s)
- Stephanie Oates
- 1King's College Hospital, London, UK.,2Evelina London Children's Hospital, London, UK
| | | | | | | | - Elaine F Hughes
- 1King's College Hospital, London, UK.,2Evelina London Children's Hospital, London, UK
| | | | | | - Qin Hao
- Amplexa Genetics, Odense, Denmark
| | | | - Rikke S Møller
- Danish National Epilepsy Centre, Dianalund, Denmark.,6Institute for Regional Health research, University of Southern Denmark, Odense, Denmark
| | - Deb K Pal
- 1King's College Hospital, London, UK.,2Evelina London Children's Hospital, London, UK.,3Kings College London, London, UK
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80
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Bertacchi M, Parisot J, Studer M. The pleiotropic transcriptional regulator COUP-TFI plays multiple roles in neural development and disease. Brain Res 2018; 1705:75-94. [PMID: 29709504 DOI: 10.1016/j.brainres.2018.04.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 12/23/2022]
Abstract
Transcription factors are expressed in a dynamic fashion both in time and space during brain development, and exert their roles by activating a cascade of multiple target genes. This implies that understanding the precise function of a transcription factor becomes a challenging task. In this review, we will focus on COUP-TFI (or NR2F1), a nuclear receptor belonging to the superfamily of the steroid/thyroid hormone receptors, and considered to be one of the major transcriptional regulators orchestrating cortical arealization, cell-type specification and maturation. Recent data have unraveled the multi-faceted functions of COUP-TFI in the development of several mouse brain structures, including the neocortex, hippocampus and ganglionic eminences. Despite NR2F1 mutations and deletions in humans have been linked to a complex neurodevelopmental disease mainly associated to optic atrophy and intellectual disability, its role during the formation of the retina and optic nerve remains unclear. In light of its major influence in cortical development, we predict that its haploinsufficiency might be the cause of other cognitive diseases, not identified so far. Mouse models offer a unique opportunity of dissecting COUP-TFI function in different regions during brain assembly; hence, the importance of comparing and discussing common points linking mouse models to human patients' symptoms.
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Affiliation(s)
- Michele Bertacchi
- Université Côte d'Azur, CNRS, Inserm, iBV - Institut de Biologie Valrose, 06108 Nice, France.
| | - Josephine Parisot
- Université Côte d'Azur, CNRS, Inserm, iBV - Institut de Biologie Valrose, 06108 Nice, France
| | - Michèle Studer
- Université Côte d'Azur, CNRS, Inserm, iBV - Institut de Biologie Valrose, 06108 Nice, France.
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81
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Genetics of Epilepsy in the Era of Precision Medicine: Implications for Testing, Treatment, and Genetic Counseling. CURRENT GENETIC MEDICINE REPORTS 2018. [DOI: 10.1007/s40142-018-0139-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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82
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Eid L, Lachance M, Hickson G, Rossignol E. Ex Utero Electroporation and Organotypic Slice Cultures of Embryonic Mouse Brains for Live-Imaging of Migrating GABAergic Interneurons. J Vis Exp 2018. [PMID: 29733310 DOI: 10.3791/57526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
GABAergic interneurons (INs) are critical components of neuronal networks that drive cognition and behavior. INs destined to populate the cortex migrate tangentially from their place of origin in the ventral telencephalon (including from the medial and caudal ganglionic eminences (MGE, CGE)) to the dorsal cortical plate in response to a variety of intrinsic and extrinsic cues. Different methodologies have been developed over the years to genetically manipulate specific pathways and investigate how they regulate the dynamic cytoskeletal changes required for proper IN migration. In utero electroporation has been extensively used to study the effect of gene repression or overexpression in specific IN subtypes while assessing the impact on morphology and final position. However, while this approach is readily used to modify radially migrating pyramidal cells, it is more technically challenging when targeting INs. In utero electroporation generates a low yield given the decreased survival rates of pups when electroporation is conducted before e14.5, as is customary when studying MGE-derived INs. In an alternative approach, MGE explants provide easy access to the MGE and facilitate the imaging of genetically modified INs. However, in these explants, INs migrate into an artificial matrix, devoid of endogenous guidance cues and thalamic inputs. This prompted us to optimize a method where INs can migrate in a more naturalistic environment, while circumventing the technical challenges of in utero approaches. In this paper, we describe the combination of ex utero electroporation of embryonic mouse brains followed by organotypic slice cultures to readily track, image and reconstruct genetically modified INs migrating along their natural paths in response to endogenous cues. This approach allows for both the quantification of the dynamic aspects of IN migration with time-lapse confocal imaging, as well as the detailed analysis of various morphological parameters using neuronal reconstructions on fixed immunolabeled tissue.
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Affiliation(s)
- Lara Eid
- Centre de recherche du CHU Sainte-Justine; Department of Neuroscience, Université de Montréal
| | | | - Gilles Hickson
- Centre de recherche du CHU Sainte-Justine; Department of pathology and cellular biology, Université de Montréal
| | - Elsa Rossignol
- Centre de recherche du CHU Sainte-Justine; Department of Neuroscience, Université de Montréal; Department of Pediatrics, Université de Montréal;
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83
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Iacobaş DA, Chachua T, Iacobaş S, Benson MJ, Borges K, Velíšková J, Velíšek L. ACTH and PMX53 recover synaptic transcriptome alterations in a rat model of infantile spasms. Sci Rep 2018; 8:5722. [PMID: 29636502 PMCID: PMC5893534 DOI: 10.1038/s41598-018-24013-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 03/22/2018] [Indexed: 12/12/2022] Open
Abstract
We profiled the gene expression in the hypothalamic arcuate nuclei (ARC) of 20 male and 20 female rats to determine the infantile spasms (IS) related transcriptomic alteration of neurotransmission and recovery following two treatments. Rats were prenatally exposed to betamethasone or saline followed by repeated postnatal subjection to NMDA-triggered IS. Rats with spasms were treated with ACTH, PMX53 or saline. Since ACTH, the first line treatment for IS, has inconsistent efficacy and potential harsh side effects, PMX53, a potent complement C5ar1 antagonist, was suggested as a therapeutic alternative given its effects in other epilepsy models. Novel measures that consider all genes and are not affected by arbitrary cut-offs were used, in addition to standard statistical tests, to quantify regulation and recovery of glutamatergic, GABAergic, cholinergic, dopaminergic and serotonergic pathways. Although IS alters expression of ~30% of the ARC genes in both sexes the transcriptomic effects are 3× more severe in males than their female counterparts, as indicated by the Weighted Pathway Regulation measure. Both treatments significantly restored the ARC neurotransmission transcriptome to the non-IS condition with PMX53 performing slightly better, as measured by the Pathway Restoration Efficiency, suggesting these treatments may reduce autistic traits often associated with IS.
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Affiliation(s)
- Dumitru A Iacobaş
- Center for Computational Systems Biology, Prairie View AM University, Prairie View, TX, 77446, USA. .,D.P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA.
| | - Tamar Chachua
- New York Medical College School of Medicine, Department of Cell Biology and Anatomy, Valhalla, NY, 10595, USA
| | - Sanda Iacobaş
- New York Medical College School of Medicine, Department of Pathology, Valhalla, NY, 10595, USA
| | - Melissa J Benson
- New York Medical College School of Medicine, Department of Cell Biology and Anatomy, Valhalla, NY, 10595, USA.,University of Queensland, School of Biomedical Sciences, Brisbane, Australia
| | - Karin Borges
- University of Queensland, School of Biomedical Sciences, Brisbane, Australia
| | - Jana Velíšková
- New York Medical College School of Medicine, Department of Cell Biology and Anatomy, Valhalla, NY, 10595, USA.,New York Medical College School of Medicine, Department of Neurology, Valhalla, NY, 10595, USA.,New York Medical College School of Medicine, Department of Obstetrics and Gynecology, Valhalla, NY, 10595, USA
| | - Libor Velíšek
- New York Medical College School of Medicine, Department of Cell Biology and Anatomy, Valhalla, NY, 10595, USA.,New York Medical College School of Medicine, Department of Neurology, Valhalla, NY, 10595, USA.,New York Medical College School of Medicine, Department of Pediatrics, Valhalla, NY, 10595, USA
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84
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Ectopic neurogenesis induced by prenatal antiepileptic drug exposure augments seizure susceptibility in adult mice. Proc Natl Acad Sci U S A 2018; 115:4270-4275. [PMID: 29610328 PMCID: PMC5910824 DOI: 10.1073/pnas.1716479115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent clinical studies suggest that environmental insults, such as valproic acid (VPA) exposure, in utero can have adverse effects on brain function of the offspring in later life, although the underlying mechanisms of these impairments remain poorly understood. By focusing on the property of neural stem/progenitor cells (NS/PCs) residing in the adult hippocampus, we identified the mechanism of increased seizure sensitivity in prenatally VPA-exposed adult mice. Furthermore, we found that voluntary exercise can overcome the adverse effects through normalizing VPA-induced transcriptome alterations in NS/PCs. We believe that our study provides insights for further understanding and developing treatment strategies for neurological disorders induced by prenatal environmental insults. Epilepsy is a neurological disorder often associated with seizure that affects ∼0.7% of pregnant women. During pregnancy, most epileptic patients are prescribed antiepileptic drugs (AEDs) such as valproic acid (VPA) to control seizure activity. Here, we show that prenatal exposure to VPA in mice increases seizure susceptibility in adult offspring through mislocalization of newborn neurons in the hippocampus. We confirmed that neurons newly generated from neural stem/progenitor cells (NS/PCs) are integrated into the granular cell layer in the adult hippocampus; however, prenatal VPA treatment altered the expression in NS/PCs of genes associated with cell migration, including CXC motif chemokine receptor 4 (Cxcr4), consequently increasing the ectopic localization of newborn neurons in the hilus. We also found that voluntary exercise in a running wheel suppressed this ectopic neurogenesis and countered the enhanced seizure susceptibility caused by prenatal VPA exposure, probably by normalizing the VPA-disrupted expression of multiple genes including Cxcr4 in adult NS/PCs. Replenishing Cxcr4 expression alone in NS/PCs was sufficient to overcome the aberrant migration of newborn neurons and increased seizure susceptibility in VPA-exposed mice. Thus, prenatal exposure to an AED, VPA, has a long-term effect on the behavior of NS/PCs in offspring, but this effect can be counteracted by a simple physical activity. Our findings offer a step to developing strategies for managing detrimental effects in offspring exposed to VPA in utero.
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85
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Ng BG, Freeze HH. Perspectives on Glycosylation and Its Congenital Disorders. Trends Genet 2018; 34:466-476. [PMID: 29606283 DOI: 10.1016/j.tig.2018.03.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/04/2018] [Accepted: 03/05/2018] [Indexed: 12/12/2022]
Abstract
Congenital disorders of glycosylation (CDG) are a rapidly expanding group of metabolic disorders that result from abnormal protein or lipid glycosylation. They are often difficult to clinically diagnose because they broadly affect many organs and functions and lack clinical uniformity. However, recent technological advances in next-generation sequencing have revealed a treasure trove of new genetic disorders, expanded the knowledge of known disorders, and showed a critical role in infectious diseases. More comprehensive genetic tools specifically tailored for mammalian cell-based models have revealed a critical role for glycosylation in pathogen-host interactions, while also identifying new CDG susceptibility genes. We highlight recent advancements that have resulted in a better understanding of human glycosylation disorders, perspectives for potential future therapies, and mysteries for which we continue to seek new insights and solutions.
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Affiliation(s)
- Bobby G Ng
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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86
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Berg AT, Chakravorty S, Koh S, Grinspan ZM, Shellhaas RA, Saneto RP, Wirrell EC, Coryell J, Chu CJ, Mytinger JR, Gaillard WD, Valencia I, Knupp KG, Loddenkemper T, Sullivan JE, Poduri A, Millichap JJ, Keator C, Wusthoff C, Ryan N, Dobyns WB, Hegde M. Why West? Comparisons of clinical, genetic and molecular features of infants with and without spasms. PLoS One 2018. [PMID: 29518120 PMCID: PMC5843222 DOI: 10.1371/journal.pone.0193599] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Infantile spasms are the defining seizures of West syndrome, a severe form of early life epilepsy with poorly-understood pathophysiology. We present a novel comparative analysis of infants with spasms versus other seizure-types and identify clinical, etiological, and molecular-genetic factors preferentially predisposing to spasms. We compared ages, clinical etiologies, and associated-genes between spasms and non-spasms groups in a multicenter cohort of 509 infants (<12months) with newly-diagnosed epilepsy. Gene ontology and pathway enrichment analysis of clinical laboratory-confirmed pathogenic variant-harboring genes was performed. Pathways, functions, and cellular compartments between spasms and non-spasms groups were compared. Spasms onset age was similar in infants initially presenting with spasms (6.1 months) versus developing spasms as a later seizure type (6.9 months) but lower in the non-spasms group (4.7 months, p<0.0001). This pattern held across most etiological categories. Gestational age negatively correlated with spasms onset-age (r = -0.29, p<0.0001) but not with non-spasm seizure age. Spasms were significantly preferentially associated with broad developmental and regulatory pathways, whereas motor functions and pathways including cellular response to stimuli, cell motility and ion transport were preferentially enriched in non-spasms. Neuronal cell-body organelles preferentially associated with spasms, while, axonal, dendritic, and synaptic regions preferentially associated with other seizures. Spasms are a clinically and biologically distinct infantile seizure type. Comparative clinical-epidemiological analyses identify the middle of the first year as the time of peak expression regardless of etiology. The inverse association with gestational age suggests the preterm brain must reach a certain post-conceptional, not just chronological, neurodevelopmental stage before spasms manifest. Clear differences exist between the biological pathways leading to spasms versus other seizure types and suggest that spasms result from dysregulation of multiple developmental pathways and involve different cellular components than other seizure types. This deeper level of understanding may guide investigations into pathways most critical to target in future precision medicine efforts.
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Affiliation(s)
- Anne T. Berg
- Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States of America
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- * E-mail:
| | - Samya Chakravorty
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Sookyong Koh
- Department of Pediatrics, Children’s Healthcare of Atlanta, Emory University, Atlanta, GA, United States of America
| | - Zachary M. Grinspan
- Department of Healthcare Policy & Research, Weill Cornell Medicine, New York, NY, United States of America
- Department Pediatrics, Weill Cornell Medicine, New York, NY, United States of America
- New York Presbyterian Hospital, New York, NY, United States of America
| | - Renée A. Shellhaas
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States of America
| | - Russell P. Saneto
- Division of Pediatric Neurology, Seattle Children’s Hospital, Seattle, WA, United States of America
- Department of Neurology, University of Washington, Seattle, WA, United States of America
| | - Elaine C. Wirrell
- Department of Neurology, Mayo Clinic, Rochester, MN, United States of America
| | - Jason Coryell
- Departments of Pediatrics & Neurology, Oregon Health & Sciences University, Portland, OR, United States of America
| | - Catherine J. Chu
- Department of Neurology, Massachusetts General Hospital, Boston, MA, United States of America
| | - John R. Mytinger
- Department of Pediatrics, the Ohio State University, Nationwide Children’s Hospital, Columbus, OH, United States of America
| | - William D. Gaillard
- Department of Neurology, Children's National Health System, George Washington University School of Medicine, Washington, D.C., United States of America
| | - Ignacio Valencia
- Section of Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA, United States of America
| | - Kelly G. Knupp
- Department of Pediatrics and Neurology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Tobias Loddenkemper
- Division of Epilepsy and Clinical Neurophysiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Joseph E. Sullivan
- Department of Neurology, University of California San Francisco, San Francisco, CA, United States of America
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States of America
| | - John J. Millichap
- Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States of America
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Cynthia Keator
- Cook Children’s Health Care System, Jane and John Justin Neurosciences Center, Fort Worth, TX, United States of America
| | - Courtney Wusthoff
- Division of Child Neurology, Stanford University, Palo Alto, CA, United States of America
| | - Nicole Ryan
- Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States of America
- The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
| | - William B. Dobyns
- Division of Pediatric Neurology, Seattle Children’s Hospital, Seattle, WA, United States of America
- Department of Neurology, University of Washington, Seattle, WA, United States of America
- Center for Integrative Brain Research, University of Washington, Seattle, WA, United States of America
- Seattle Children's Research Institute, University of Washington, Seattle, WA, United States of America
- Pediatrics University of Washington, Seattle, WA, United States of America
| | - Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States of America
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87
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Ko A, Youn SE, Kim SH, Lee JS, Kim S, Choi JR, Kim HD, Lee ST, Kang HC. Targeted gene panel and genotype-phenotype correlation in children with developmental and epileptic encephalopathy. Epilepsy Res 2018; 141:48-55. [DOI: 10.1016/j.eplepsyres.2018.02.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/20/2018] [Accepted: 02/07/2018] [Indexed: 01/17/2023]
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Abstract
Infantile spasms are a devastating epileptic encephalopathy characterized by early life spasms and later seizures. Clinical outcomes of infantile spasms are poor and therapeutic options are limited with significant adverse effects. Therefore, new strategies to treat infantile spasms are of the utmost importance. Animals models of infantile spasms are a critical component of developing new therapies. Here, we review current chronic animal models of infantile spasms and consider future advances that may help improve patient care, as well as our scientific understanding of this debilitating disease.
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Two microcephaly-associated novel missense mutations in CASK specifically disrupt the CASK-neurexin interaction. Hum Genet 2018; 137:231-246. [PMID: 29426960 DOI: 10.1007/s00439-018-1874-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/31/2018] [Indexed: 12/23/2022]
Abstract
Deletion and truncation mutations in the X-linked gene CASK are associated with severe intellectual disability (ID), microcephaly and pontine and cerebellar hypoplasia in girls (MICPCH). The molecular origin of CASK-linked MICPCH is presumed to be due to disruption of the CASK-Tbr-1 interaction. This hypothesis, however, has not been directly tested. Missense variants in CASK are typically asymptomatic in girls. We report three severely affected girls with heterozygous CASK missense mutations (M519T (2), G659D (1)) who exhibit ID, microcephaly, and hindbrain hypoplasia. The mutation M519T results in the replacement of an evolutionarily invariant methionine located in the PDZ signaling domain known to be critical for the CASK-neurexin interaction. CASKM519T is incapable of binding to neurexin, suggesting a critically important role for the CASK-neurexin interaction. The mutation G659D is in the SH3 (Src homology 3) domain of CASK, replacing a semi-conserved glycine with aspartate. We demonstrate that the CASKG659D mutation affects the CASK protein in two independent ways: (1) it increases the protein's propensity to aggregate; and (2) it disrupts the interface between CASK's PDZ (PSD95, Dlg, ZO-1) and SH3 domains, inhibiting the CASK-neurexin interaction despite residing outside of the domain deemed critical for neurexin interaction. Since heterozygosity of other aggregation-inducing mutations (e.g., CASKW919R) does not produce MICPCH, we suggest that the G659D mutation produces microcephaly by disrupting the CASK-neurexin interaction. Our results suggest that disruption of the CASK-neurexin interaction, not the CASK-Tbr-1 interaction, produces microcephaly and cerebellar hypoplasia. These findings underscore the importance of functional validation for variant classification.
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90
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Mutoh H, Kato M, Akita T, Shibata T, Wakamoto H, Ikeda H, Kitaura H, Aoto K, Nakashima M, Wang T, Ohba C, Miyatake S, Miyake N, Kakita A, Miyake K, Fukuda A, Matsumoto N, Saitsu H. Biallelic Variants in CNPY3, Encoding an Endoplasmic Reticulum Chaperone, Cause Early-Onset Epileptic Encephalopathy. Am J Hum Genet 2018; 102:321-329. [PMID: 29394991 DOI: 10.1016/j.ajhg.2018.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/08/2018] [Indexed: 12/22/2022] Open
Abstract
Early-onset epileptic encephalopathies, including West syndrome (WS), are a group of neurological disorders characterized by developmental impairments and intractable seizures from early infancy. We have now identified biallelic CNPY3 variants in three individuals with WS; these include compound-heterozygous missense and frameshift variants in a family with two affected siblings (individuals 1 and 2) and a homozygous splicing variant in a consanguineous family (individual 3). All three individuals showed hippocampal malrotation. In individuals 1 and 2, electroencephalography (EEG) revealed characteristic fast waves and diffuse sharp- and slow-wave complexes. The fast waves were clinically associated with seizures. CNPY3 encodes a co-chaperone in the endoplasmic reticulum and regulates the subcellular distribution and responses of multiple Toll-like receptors. The amount of CNPY3 in lymphoblastoid cells derived from individuals 1 and 2 was severely lower than that in control cells. Cnpy3-knockout mice exhibited spastic or dystonic features under resting conditions and hyperactivity and anxiolytic behavior during the open field test. Also, their resting EEG showed enhanced activity in the fast beta frequency band (20-35 Hz), which could mimic the fast waves in individuals 1 and 2. These data suggest that CNPY3 and Cnpy3 perform essential roles in brain function in addition to known Toll-like receptor-dependent immune responses.
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Affiliation(s)
- Hiroki Mutoh
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo 142-8666, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Takuma Shibata
- Division of Infectious Genetics, Department of Microbiology and Immunology, University of Tokyo, Tokyo 108-8639, Japan
| | - Hiroyuki Wakamoto
- Department of Pediatrics, Ehime Rehabilitation Center for Children, Ehime 791-0212, Japan
| | - Hiroko Ikeda
- Department of Pediatrics, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, National Hospital Organization, Shizuoka 420-8688, Japan
| | - Hiroki Kitaura
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata 951-8585, Japan
| | - Kazushi Aoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Tianying Wang
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata 951-8585, Japan
| | - Kensuke Miyake
- Division of Infectious Genetics, Department of Microbiology and Immunology, University of Tokyo, Tokyo 108-8639, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
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91
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Zhou P, He N, Zhang JW, Lin ZJ, Wang J, Yan LM, Meng H, Tang B, Li BM, Liu XR, Shi YW, Zhai QX, Yi YH, Liao WP. Novel mutations and phenotypes of epilepsy-associated genes in epileptic encephalopathies. GENES BRAIN AND BEHAVIOR 2018; 17:e12456. [PMID: 29314583 DOI: 10.1111/gbb.12456] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/13/2017] [Accepted: 12/30/2017] [Indexed: 12/30/2022]
Abstract
Epileptic encephalopathies are severe epilepsy disorders with strong genetic bases. We performed targeted next-generation sequencing (NGS) in 70 patients with epileptic encephalopathies. The likely pathogenicity of variants in candidate genes was evaluated by American College of Medical Genetics and Genomics (ACMG) scoring taken together with the accepted clinical presentation. Thirty-three candidate variants were detected after population filtration and computational prediction. According to ACMG, 21 candidate variants, including 18 de novo variants, were assessed to be pathogenic/likely pathogenic with clinical concordance. Twelve variants were initially assessed as uncertain significance by ACMG, among which 3 were considered causative and 3 others were considered possibly causative after analysis of clinical concordance. In total, 24 variants were identified as putatively causative, among which 19 were novel findings. SCN1A mutations were identified in 50% of patients with Dravet syndrome. TSC1/TSC2 mutations were detected in 66.7% of patients with tuberous sclerosis. STXBP1 mutations were the main findings in patients with West syndrome. Mutations in SCN2A, KCNT1, KCNQ2 and CLCN4 were identified in patients with epileptic infantile with migrating focal seizures; among them, KCNQ2 and CLCN4 were first identified as potential causative genes. Only one CHD2 mutation was detected in patients with Lennox-Gastaut syndrome. This study highlighted the utility of targeted NGS in genetic diagnoses of epileptic encephalopathies and a comprehensive evaluation of the pathogenicity of variants based on ACMG scoring and assessment of clinical concordance. Epileptic encephalopathies differ in genetic causes, and the genotype-phenotype correlations would provide insights into the underlying pathogenic mechanisms.
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Affiliation(s)
- P Zhou
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - N He
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - J-W Zhang
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Z-J Lin
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - J Wang
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - L-M Yan
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - H Meng
- Department of Neurology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Clinical Neuroscience Institute, Jinan University, Guangzhou, China
| | - B Tang
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - B-M Li
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - X-R Liu
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Y-W Shi
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Q-X Zhai
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Y-H Yi
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - W-P Liao
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
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92
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Ortega-Moreno L, Giráldez BG, Soto-Insuga V, Losada-Del Pozo R, Rodrigo-Moreno M, Alarcón-Morcillo C, Sánchez-Martín G, Díaz-Gómez E, Guerrero-López R, Serratosa JM. Molecular diagnosis of patients with epilepsy and developmental delay using a customized panel of epilepsy genes. PLoS One 2017; 12:e0188978. [PMID: 29190809 PMCID: PMC5708701 DOI: 10.1371/journal.pone.0188978] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022] Open
Abstract
Pediatric epilepsies are a group of disorders with a broad phenotypic spectrum that are associated with great genetic heterogeneity, thus making sequential single-gene testing an impractical basis for diagnostic strategy. The advent of next-generation sequencing has increased the success rate of epilepsy diagnosis, and targeted resequencing using genetic panels is the a most cost-effective choice. We report the results found in a group of 87 patients with epilepsy and developmental delay using targeted next generation sequencing (custom-designed Haloplex panel). Using this gene panel, we were able to identify disease-causing variants in 17 out of 87 (19.5%) analyzed patients, all found in known epilepsy-associated genes (KCNQ2, CDKL5, STXBP1, SCN1A, PCDH19, POLG, SLC2A1, ARX, ALG13, CHD2, SYNGAP1, and GRIN1). Twelve of 18 variants arose de novo and 6 were novel. The highest yield was found in patients with onset in the first years of life, especially in patients classified as having early-onset epileptic encephalopathy. Knowledge of the underlying genetic cause provides essential information on prognosis and could be used to avoid unnecessary studies, which may result in a greater diagnostic cost-effectiveness.
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Affiliation(s)
- Laura Ortega-Moreno
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Beatriz G. Giráldez
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Victor Soto-Insuga
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - Rebeca Losada-Del Pozo
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - María Rodrigo-Moreno
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - Cristina Alarcón-Morcillo
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Gema Sánchez-Martín
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Esther Díaz-Gómez
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Rosa Guerrero-López
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - José M. Serratosa
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
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93
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Hamdan FF, Myers CT, Cossette P, Lemay P, Spiegelman D, Laporte AD, Nassif C, Diallo O, Monlong J, Cadieux-Dion M, Dobrzeniecka S, Meloche C, Retterer K, Cho MT, Rosenfeld JA, Bi W, Massicotte C, Miguet M, Brunga L, Regan BM, Mo K, Tam C, Schneider A, Hollingsworth G, FitzPatrick DR, Donaldson A, Canham N, Blair E, Kerr B, Fry AE, Thomas RH, Shelagh J, Hurst JA, Brittain H, Blyth M, Lebel RR, Gerkes EH, Davis-Keppen L, Stein Q, Chung WK, Dorison SJ, Benke PJ, Fassi E, Corsten-Janssen N, Kamsteeg EJ, Mau-Them FT, Bruel AL, Verloes A, Õunap K, Wojcik MH, Albert DV, Venkateswaran S, Ware T, Jones D, Liu YC, Mohammad SS, Bizargity P, Bacino CA, Leuzzi V, Martinelli S, Dallapiccola B, Tartaglia M, Blumkin L, Wierenga KJ, Purcarin G, O’Byrne JJ, Stockler S, Lehman A, Keren B, Nougues MC, Mignot C, Auvin S, Nava C, Hiatt SM, Bebin M, Shao Y, Scaglia F, Lalani SR, Frye RE, Jarjour IT, Jacques S, Boucher RM, Riou E, Srour M, Carmant L, Lortie A, Major P, Diadori P, Dubeau F, D’Anjou G, Bourque G, Berkovic SF, Sadleir LG, Campeau PM, Kibar Z, Lafrenière RG, Girard SL, Mercimek-Mahmutoglu S, Boelman C, Rouleau GA, Scheffer IE, Mefford HC, Andrade DM, Rossignol E, Minassian BA, Michaud JL, Michaud JL. High Rate of Recurrent De Novo Mutations in Developmental and Epileptic Encephalopathies. Am J Hum Genet 2017; 101:664-685. [PMID: 29100083 DOI: 10.1016/j.ajhg.2017.09.008] [Citation(s) in RCA: 308] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/11/2017] [Indexed: 12/30/2022] Open
Abstract
Developmental and epileptic encephalopathy (DEE) is a group of conditions characterized by the co-occurrence of epilepsy and intellectual disability (ID), typically with developmental plateauing or regression associated with frequent epileptiform activity. The cause of DEE remains unknown in the majority of cases. We performed whole-genome sequencing (WGS) in 197 individuals with unexplained DEE and pharmaco-resistant seizures and in their unaffected parents. We focused our attention on de novo mutations (DNMs) and identified candidate genes containing such variants. We sought to identify additional subjects with DNMs in these genes by performing targeted sequencing in another series of individuals with DEE and by mining various sequencing datasets. We also performed meta-analyses to document enrichment of DNMs in candidate genes by leveraging our WGS dataset with those of several DEE and ID series. By combining these strategies, we were able to provide a causal link between DEE and the following genes: NTRK2, GABRB2, CLTC, DHDDS, NUS1, RAB11A, GABBR2, and SNAP25. Overall, we established a molecular diagnosis in 63/197 (32%) individuals in our WGS series. The main cause of DEE in these individuals was de novo point mutations (53/63 solved cases), followed by inherited mutations (6/63 solved cases) and de novo CNVs (4/63 solved cases). De novo missense variants explained a larger proportion of individuals in our series than in other series that were primarily ascertained because of ID. Moreover, these DNMs were more frequently recurrent than those identified in ID series. These observations indicate that the genetic landscape of DEE might be different from that of ID without epilepsy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Jacques L Michaud
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T1C5, Canada; Department of Neurosciences, Université de Montréal, Montreal, QC H3T1J4, Canada; Department of Pediatrics, Université de Montréal, Montreal, QC H3T1C5, Canada.
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94
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Myers CT, Stong N, Mountier EI, Helbig KL, Freytag S, Sullivan JE, Ben Zeev B, Nissenkorn A, Tzadok M, Heimer G, Shinde DN, Rezazadeh A, Regan BM, Oliver KL, Ernst ME, Lippa NC, Mulhern MS, Ren Z, Poduri A, Andrade DM, Bird LM, Bahlo M, Berkovic SF, Lowenstein DH, Scheffer IE, Sadleir LG, Goldstein DB, Mefford HC, Heinzen EL. De Novo Mutations in PPP3CA Cause Severe Neurodevelopmental Disease with Seizures. Am J Hum Genet 2017; 101:516-524. [PMID: 28942967 DOI: 10.1016/j.ajhg.2017.08.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/10/2017] [Indexed: 12/30/2022] Open
Abstract
Exome sequencing has readily enabled the discovery of the genetic mutations responsible for a wide range of diseases. This success has been particularly remarkable in the severe epilepsies and other neurodevelopmental diseases for which rare, often de novo, mutations play a significant role in disease risk. Despite significant progress, the high genetic heterogeneity of these disorders often requires large sample sizes to identify a critical mass of individuals with disease-causing mutations in a single gene. By pooling genetic findings across multiple studies, we have identified six individuals with severe developmental delay (6/6), refractory seizures (5/6), and similar dysmorphic features (3/6), each harboring a de novo mutation in PPP3CA. PPP3CA encodes the alpha isoform of a subunit of calcineurin. Calcineurin encodes a calcium- and calmodulin-dependent serine/threonine protein phosphatase that plays a role in a wide range of biological processes, including being a key regulator of synaptic vesicle recycling at nerve terminals. Five individuals with de novo PPP3CA mutations were identified among 4,760 trio probands with neurodevelopmental diseases; this is highly unlikely to occur by chance (p = 1.2 × 10-8) given the size and mutability of the gene. Additionally, a sixth individual with a de novo mutation in PPP3CA was connected to this study through GeneMatcher. Based on these findings, we securely implicate PPP3CA in early-onset refractory epilepsy and further support the emerging role for synaptic dysregulation in epilepsy.
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Affiliation(s)
- Candace T Myers
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Nicholas Stong
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Emily I Mountier
- Department of Paediatrics and Child Health, University of Otago, Wellington 6242, New Zealand
| | | | - Saskia Freytag
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3050, Australia
| | - Joseph E Sullivan
- Department of Neurology & Pediatrics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Bruria Ben Zeev
- Sheba Medical Center, Ramat Gan, Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Andreea Nissenkorn
- Sheba Medical Center, Ramat Gan, Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Michal Tzadok
- Sheba Medical Center, Ramat Gan, Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Gali Heimer
- Sheba Medical Center, Ramat Gan, Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | | | - Arezoo Rezazadeh
- Division of Neurology, Epilepsy Genetics Research Program, Toronto Western Hospital, Krembil Neuroscience Centre, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Brigid M Regan
- Division of Neurology, Epilepsy Genetics Research Program, Toronto Western Hospital, Krembil Neuroscience Centre, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Karen L Oliver
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, VIC 3084, Australia
| | - Michelle E Ernst
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Natalie C Lippa
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Maureen S Mulhern
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Zhong Ren
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Danielle M Andrade
- Division of Neurology, Epilepsy Genetics Research Program, Toronto Western Hospital, Krembil Neuroscience Centre, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Lynne M Bird
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92037, USA; Rady Children's Hospital, San Diego, CA 92037, USA
| | - Melanie Bahlo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3050, Australia
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, VIC 3084, Australia
| | - Daniel H Lowenstein
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, VIC 3084, Australia; Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Parkville, VIC 3050, Australia
| | - Lynette G Sadleir
- Department of Paediatrics and Child Health, University of Otago, Wellington 6242, New Zealand
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA.
| | - Erin L Heinzen
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA.
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Galama WH, Verhaagen-van den Akker SLJ, Lefeber DJ, Feenstra I, Verrips A. ALG13-CDG with Infantile Spasms in a Male Patient Due to a De Novo ALG13 Gene Mutation. JIMD Rep 2017; 40:11-16. [PMID: 28887793 DOI: 10.1007/8904_2017_53] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 07/20/2017] [Accepted: 07/28/2017] [Indexed: 01/06/2023] Open
Abstract
A boy presented at the age of 3.5 months with a developmental delay. He developed infantile spasms with hypsarrhytmia on EEG 1 month later. Additional symptoms were delayed visual development, asymmetrical hearing loss, hypotonia, and choreoathetoid movements. He also had some dysmorphic features and was vulnerable for infections. He was treated successively with vigabatrin, prednisolone, valproic acid, nitrazepam, and lamotrigine without a lasting clinical effect, but showed a treatment response to levetiracetam. Cerebral MRI showed hypoplasia of the corpus callosum and a mild delay in myelination. Further investigations including metabolic screening and glycosylation studies by transferrin isoelectric focusing were all considered to be normal. Whole-exome sequencing identified a de novo mutation in the ALG13 gene (c.320A>G, p.(Asn107Ser)). Mutations in this gene, which is located on the X-chromosome, are associated with congenital disorders of glycosylation type I (CDG-I). Mass spectrometric analysis of transferrin showed minor glycosylation abnormalities. The c.320A>G mutation in ALG13 has until now only been described in girls and was thought to be lethal for boys. All girls with this specific mutation presented with a similar phenotype of developmental delay and severe early onset epilepsy. In two girls glycosylation studies were performed which showed a normal glycosylation pattern. This is the first boy presenting with an epileptic encephalopathy caused by the c.320A>G mutation in the ALG13 gene. Since glycosylation studies are near-normal in patients with this mutation, the diagnosis of ALG13-CDG can be missed if genetic studies are not performed.
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Affiliation(s)
- Wienke H Galama
- Department of Neurology/Pediatric Neurology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
| | | | - Dirk J Lefeber
- Department of Neurology, Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Ilse Feenstra
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Aad Verrips
- Department of Neurology/Pediatric Neurology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
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Jackson MR, Lee K, Mattiske T, Jaehne EJ, Ozturk E, Baune BT, O'Brien TJ, Jones N, Shoubridge C. Extensive phenotyping of two ARX polyalanine expansion mutation mouse models that span clinical spectrum of intellectual disability and epilepsy. Neurobiol Dis 2017; 105:245-256. [DOI: 10.1016/j.nbd.2017.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/30/2017] [Accepted: 05/29/2017] [Indexed: 11/17/2022] Open
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Gadomski TE, Bolton M, Alfadhel M, Dvorak C, Ogunsakin OA, Nelson SL, Morava E. ALG13-CDG in a male with seizures, normal cognitive development, and normal transferrin isoelectric focusing. Am J Med Genet A 2017; 173:2772-2775. [DOI: 10.1002/ajmg.a.38377] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 06/26/2017] [Accepted: 07/01/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Therese E. Gadomski
- Hayward Genetics Center; Tulane University School of Medicine; New Orleans Louisiana
- Department of Pediatrics; Tulane University School of Medicine; New Orleans Louisiana
| | - Melody Bolton
- Hayward Genetics Center; Tulane University School of Medicine; New Orleans Louisiana
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdullah International Medical Research Centre, King Abdulaziz Medical City; King Saud bin Abdulaziz University for Health Sciences; Riyadh Saudi Arabia
| | - Chris Dvorak
- Hayward Genetics Center; Tulane University School of Medicine; New Orleans Louisiana
| | - Olalekan A. Ogunsakin
- Hayward Genetics Center; Tulane University School of Medicine; New Orleans Louisiana
| | - Stephen L. Nelson
- Department of Pediatrics; Tulane University School of Medicine; New Orleans Louisiana
| | - Eva Morava
- Hayward Genetics Center; Tulane University School of Medicine; New Orleans Louisiana
- Department of Pediatrics; Tulane University School of Medicine; New Orleans Louisiana
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98
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Exome sequence identified a c.320A > G ALG13 variant in a female with infantile epileptic encephalopathy with normal glycosylation and random X inactivation: Review of the literature. Eur J Med Genet 2017; 60:541-547. [PMID: 28778787 DOI: 10.1016/j.ejmg.2017.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/12/2017] [Accepted: 07/30/2017] [Indexed: 12/24/2022]
Abstract
Congenital Disorders of Glycosylation (CDG) are new and rapidly expanding neurometabolic disorders with multisystem involvements, broad phenotypic manifestations, and variable severity. The majority results from a defect of one of the steps involved with protein or lipid N-glycosylation pathway. Almost all are inherited in autosomal recessive patterns with a few exceptions such as the X-linked ALG13. Mutations of ALG13 are reported, so far in only 10 patients, all were ascertained through exome/genome sequencing. Specifically, the ALG13 c.320A > G (p.Asn107Ser) variant was reported only in females and in all were de novo mutations. These findings may suggest an X-linked dominant inheritance of this mutation with embryonic male lethality. These patients presented with severe infantile epileptic encephalopathy, global developmental delay, and multisystem abnormalities. Only two of these females had glycosylation studies done, and both showed normal pattern of glycosylated serum transferrin isoforms, and none had their X-chromosome inactivation patterns studied. Here, we report on another female patient who is heterozygous for the same ALG13 c.320A > G (p.Asn107Ser) variant. She presented with infantile spasms, epileptic encephalopathy, hypsarrhythmia, hypotonia, developmental delay, intellectual disability, abnormal coagulation profile, feeding problems, hypotonia, and dysmorphic features. The diagnosis of CGD was suspected clinically, but glycosylation studies were done twice and showed normal patterns on both occasions. Her X-inactivation study was also done and, surprisingly, showed a random pattern of X-inactivation, with no evidence of skewness.
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99
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Abstract
Epileptic encephalopathies represent a particularly severe form of epilepsy, associated with cognitive and behavioral deficits, including impaired social-communication and restricted, repetitive behaviors that are the hallmarks of autism spectrum disorder (ASD). With the advent of next-generation sequencing, the genetic landscape of epileptic encephalopathies is growing and demonstrates overlap with genes separately implicated in ASD. However, many questions remain about this connection, including whether epileptiform activity itself contributes to the development of ASD symptomatology. In this review, we compiled a database of genes associated with both epileptic encephalopathy and ASD, limiting our purview to Mendelian disorders not including inborn errors of metabolism, and we focused on the connection between ASD and epileptic encephalopathy rather than epilepsy broadly. Our review has four goals: to (1) discuss the overlapping presentations of ASD and monogenic epileptic encephalopathies; (2) examine the impact of the epilepsy itself on neurocognitive features, including ASD, in monogenic epileptic encephalopathies; (3) outline many of the genetic causes responsible for both ASD and epileptic encephalopathy; (4) provide an illustrative example of a final common pathway that may be implicated in both ASD and epileptic encephalopathy. We demonstrate that autistic features are a common association with monogenic epileptic encephalopathies. Certain epileptic encephalopathy syndromes, like infantile spasms, are especially linked to the development of ASD. The connection between seizures themselves and neurobehavioral deficits in these monogenic encephalopathies remains open to debate. Finally, advances in genetics have revealed many genes that overlap in ties to both ASD and epileptic encephalopathy and that play a role in diverse central nervous system processes. Increased attention to the autistic features of monogenic epileptic encephalopathies is warranted for both researchers and clinicians alike.
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Affiliation(s)
- Siddharth Srivastava
- Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115 USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115 USA
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100
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Suri M, Evers JMG, Laskowski RA, O'Brien S, Baker K, Clayton-Smith J, Dabir T, Josifova D, Joss S, Kerr B, Kraus A, McEntagart M, Morton J, Smith A, Splitt M, Thornton JM, Wright CF. Protein structure and phenotypic analysis of pathogenic and population missense variants in STXBP1. Mol Genet Genomic Med 2017; 5:495-507. [PMID: 28944233 PMCID: PMC5606886 DOI: 10.1002/mgg3.304] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/17/2017] [Accepted: 05/20/2017] [Indexed: 01/07/2023] Open
Abstract
Background Syntaxin‐binding protein 1, encoded by STXBP1, is highly expressed in the brain and involved in fusing synaptic vesicles with the plasma membrane. Studies have shown that pathogenic loss‐of‐function variants in this gene result in various types of epilepsies, mostly beginning early in life. We were interested to model pathogenic missense variants on the protein structure to investigate the mechanism of pathogenicity and genotype–phenotype correlations. Methods We report 11 patients with pathogenic de novo mutations in STXBP1 identified in the first 4293 trios of the Deciphering Developmental Disorder (DDD) study, including six missense variants. We analyzed the structural locations of the pathogenic missense variants from this study and the literature, as well as population missense variants extracted from Exome Aggregation Consortium (ExAC). Results Pathogenic variants are significantly more likely to occur at highly conserved locations than population variants, and be buried inside the protein domain. Pathogenic mutations are also more likely to destabilize the domain structure compared with population variants, increasing the proportion of (partially) unfolded domains that are prone to aggregation or degradation. We were unable to detect any genotype–phenotype correlation, but unlike previously reported cases, most of the DDD patients with STXBP1 pathogenic variants did not present with very early‐onset or severe epilepsy and encephalopathy, though all have developmental delay with intellectual disability and most display behavioral problems and suffered seizures in later childhood. Conclusion Variants across STXBP1 that cause loss of function can result in severe intellectual disability with or without seizures, consistent with a haploinsufficiency mechanism. Pathogenic missense mutations act through destabilization of the protein domain, making it prone to aggregation or degradation. The presence or absence of early seizures may reflect ascertainment bias in the literature as well as the broad recruitment strategy of the DDD study.
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Affiliation(s)
- Mohnish Suri
- Nottingham Regional Genetics ServiceNottingham University Hospitals NHS TrustCity Hospital Campus, The Gables, Hucknall RoadNottinghamNG5 1PBUK
| | - Jochem M G Evers
- European Bioinformatics Institute (EMBL-EBI)Wellcome Genome Campus, HinxtonCambridgeCB10 1SDUK
| | - Roman A Laskowski
- European Bioinformatics Institute (EMBL-EBI)Wellcome Genome Campus, HinxtonCambridgeCB10 1SDUK
| | - Sinead O'Brien
- MRC Cognition and Brain Sciences Unit15 Chaucer RoadCambridgeCB2 7EFUK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit15 Chaucer RoadCambridgeCB2 7EFUK.,Department of Medical GeneticsUniversity of CambridgeCambridge Biomedical CampusCambridgeCB2 0QQUK
| | - Jill Clayton-Smith
- Manchester Centre for Genomic MedicineSt Mary's Hospital, Central Manchester University Hospitals NHS Foundation TrustManchester Academic Health Science CentreManchesterM13 9WLUK
| | - Tabib Dabir
- Northern Ireland Regional Genetics CentreBelfast Health and Social Care TrustBelfast City HospitalLisburn RoadBelfastBT9 7ABUK
| | - Dragana Josifova
- South East Thames Regional Genetics CentreGuy's and St Thomas' NHS Foundation TrustGuy's HospitalGreat Maze PondLondonSE1 9RTUK
| | - Shelagh Joss
- West of Scotland Genetics ServiceQueen Elizabeth University HospitalLaboratory Medicine BuildingGlasgowG51 4TFUK
| | - Bronwyn Kerr
- Manchester Centre for Genomic MedicineSt Mary's Hospital, Central Manchester University Hospitals NHS Foundation TrustManchester Academic Health Science CentreManchesterM13 9WLUK
| | - Alison Kraus
- Yorkshire Regional Genetics ServiceDepartment of Clinical GeneticsLeeds Teaching Hospitals NHS TrustChapel Allerton HospitalChapeltown RoadLeedsLS7 4SAUK
| | - Meriel McEntagart
- South West Thames Regional Genetics CentreSt George's Healthcare NHS TrustSt George's University of LondonCranmer TerraceLondonSW17 0REUK
| | - Jenny Morton
- West Midlands Regional Clinical Genetics Service and Birmingham Health PartnersBirmingham Women's and Children's NHS Foundation TrustBirmingham Women's HospitalMindelsohn Way, EdgbastonBirminghamB15 2TGUK
| | - Audrey Smith
- Yorkshire Regional Genetics ServiceDepartment of Clinical GeneticsLeeds Teaching Hospitals NHS TrustChapel Allerton HospitalChapeltown RoadLeedsLS7 4SAUK
| | - Miranda Splitt
- Northern Genetics ServiceNewcastle upon Tyne Hospitals NHS Foundation TrustInstitute of Human GeneticsInternational Centre for LifeCentral ParkwayNewcastle upon TyneNE1 3BZUK
| | - Janet M Thornton
- European Bioinformatics Institute (EMBL-EBI)Wellcome Genome Campus, HinxtonCambridgeCB10 1SDUK
| | | | - Caroline F Wright
- Wellcome Trust Sanger InstituteWellcome Genome Campus, HinxtonCambridgeCB1 8RQUK.,University of Exeter Medical SchoolRoyal Devon & Exeter HospitalBarrack RoadExeterEX2 5DWUK
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