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Corbett MA, Kroes T, Veneziano L, Bennett MF, Florian R, Schneider AL, Coppola A, Licchetta L, Franceschetti S, Suppa A, Wenger A, Mei D, Pendziwiat M, Kaya S, Delledonne M, Straussberg R, Xumerle L, Regan B, Crompton D, van Rootselaar AF, Correll A, Catford R, Bisulli F, Chakraborty S, Baldassari S, Tinuper P, Barton K, Carswell S, Smith M, Berardelli A, Carroll R, Gardner A, Friend KL, Blatt I, Iacomino M, Di Bonaventura C, Striano S, Buratti J, Keren B, Nava C, Forlani S, Rudolf G, Hirsch E, Leguern E, Labauge P, Balestrini S, Sander JW, Afawi Z, Helbig I, Ishiura H, Tsuji S, Sisodiya SM, Casari G, Sadleir LG, van Coller R, Tijssen MAJ, Klein KM, van den Maagdenberg AMJM, Zara F, Guerrini R, Berkovic SF, Pippucci T, Canafoglia L, Bahlo M, Striano P, Scheffer IE, Brancati F, Depienne C, Gecz J. Intronic ATTTC repeat expansions in STARD7 in familial adult myoclonic epilepsy linked to chromosome 2. Nat Commun 2019; 10:4920. [PMID: 31664034 PMCID: PMC6820779 DOI: 10.1038/s41467-019-12671-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/23/2019] [Indexed: 12/22/2022] Open
Abstract
Familial Adult Myoclonic Epilepsy (FAME) is characterised by cortical myoclonic tremor usually from the second decade of life and overt myoclonic or generalised tonic-clonic seizures. Four independent loci have been implicated in FAME on chromosomes (chr) 2, 3, 5 and 8. Using whole genome sequencing and repeat primed PCR, we provide evidence that chr2-linked FAME (FAME2) is caused by an expansion of an ATTTC pentamer within the first intron of STARD7. The ATTTC expansions segregate in 158/158 individuals typically affected by FAME from 22 pedigrees including 16 previously reported families recruited worldwide. RNA sequencing from patient derived fibroblasts shows no accumulation of the AUUUU or AUUUC repeat sequences and STARD7 gene expression is not affected. These data, in combination with other genes bearing similar mutations that have been implicated in FAME, suggest ATTTC expansions may cause this disorder, irrespective of the genomic locus involved.
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Helbig I, Riggs ER, Barry CA, Klein KM, Dyment D, Thaxton C, Sadikovic B, Sands TT, Wagnon JL, Liaquat K, Cilio MR, Mirzaa G, Park K, Axeen E, Butler E, Bardakjian TM, Striano P, Poduri A, Siegert RK, Grant AR, Helbig KL, Mefford HC. The ClinGen Epilepsy Gene Curation Expert Panel-Bridging the divide between clinical domain knowledge and formal gene curation criteria. Hum Mutat 2019; 39:1476-1484. [PMID: 30311377 DOI: 10.1002/humu.23632] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Accepted: 08/28/2018] [Indexed: 01/03/2023]
Abstract
The field of epilepsy genetics is advancing rapidly and epilepsy is emerging as a frequent indication for diagnostic genetic testing. Within the larger ClinGen framework, the ClinGen Epilepsy Gene Curation Expert Panel is tasked with connecting two increasingly separate fields: the domain of traditional clinical epileptology, with its own established language and classification criteria, and the rapidly evolving area of diagnostic genetic testing that adheres to formal criteria for gene and variant curation. We identify critical components unique to the epilepsy gene curation effort, including: (a) precise phenotype definitions within existing disease and phenotype ontologies; (b) consideration of when epilepsy should be curated as a distinct disease entity; (c) strategies for gene selection; and (d) emerging rules for evaluating functional models for seizure disorders. Given that de novo variants play a prominent role in many of the epilepsies, sufficient genetic evidence is often awarded early in the curation process. Therefore, the emphasis of gene curation is frequently shifted toward an iterative precuration process to better capture phenotypic associations. We demonstrate that within the spectrum of neurodevelopmental disorders, gene curation for epilepsy-associated genes is feasible and suggest epilepsy-specific conventions, laying the groundwork for a curation process of all major epilepsy-associated genes.
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103
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Mignot C, McMahon AC, Bar C, Campeau PM, Davidson C, Buratti J, Nava C, Jacquemont ML, Tallot M, Milh M, Edery P, Marzin P, Barcia G, Barnerias C, Besmond C, Bienvenu T, Bruel AL, Brunga L, Ceulemans B, Coubes C, Cristancho AG, Cunningham F, Dehouck MB, Donner EJ, Duban-Bedu B, Dubourg C, Gardella E, Gauthier J, Geneviève D, Gobin-Limballe S, Goldberg EM, Hagebeuk E, Hamdan FF, Hančárová M, Hubert L, Ioos C, Ichikawa S, Janssens S, Journel H, Kaminska A, Keren B, Koopmans M, Lacoste C, Laššuthová P, Lederer D, Lehalle D, Marjanovic D, Métreau J, Michaud JL, Miller K, Minassian BA, Morales J, Moutard ML, Munnich A, Ortiz-Gonzalez XR, Pinard JM, Prchalová D, Putoux A, Quelin C, Rosen AR, Roume J, Rossignol E, Simon MEH, Smol T, Shur N, Shelihan I, Štěrbová K, Vyhnálková E, Vilain C, Soblet J, Smits G, Yang SP, van der Smagt JJ, van Hasselt PM, van Kempen M, Weckhuysen S, Helbig I, Villard L, Héron D, Koeleman B, Møller RS, Lesca G, Helbig KL, Nabbout R, Verbeek NE, Depienne C. Correction: IQSEC2-related encephalopathy in males and females: a comparative study including 37 novel patients. Genet Med 2019; 21:1897-1898. [PMID: 30279470 PMCID: PMC7608434 DOI: 10.1038/s41436-018-0327-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This Article was originally published under Nature Research's License to Publish, but has now been made available under a CC BY 4.0 license. The PDF and HTML versions of the Article have been modified accordingly.
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Feng YCA, Howrigan DP, Abbott LE, Tashman K, Cerrato F, Singh T, Heyne H, Byrnes A, Churchhouse C, Watts N, Solomonson M, Lal D, Heinzen EL, Dhindsa RS, Stanley KE, Cavalleri GL, Hakonarson H, Helbig I, Krause R, May P, Weckhuysen S, Petrovski S, Kamalakaran S, Sisodiya SM, Cossette P, Cotsapas C, De Jonghe P, Dixon-Salazar T, Guerrini R, Kwan P, Marson AG, Stewart R, Depondt C, Dlugos DJ, Scheffer IE, Striano P, Freyer C, McKenna K, Regan BM, Bellows ST, Leu C, Bennett CA, Johns EM, Macdonald A, Shilling H, Burgess R, Weckhuysen D, Bahlo M, O’Brien TJ, Todaro M, Stamberger H, Andrade DM, Sadoway TR, Mo K, Krestel H, Gallati S, Papacostas SS, Kousiappa I, Tanteles GA, Štěrbová K, Vlčková M, Sedláčková L, Laššuthová P, Klein KM, Rosenow F, Reif PS, Knake S, Kunz WS, Zsurka G, Elger CE, Bauer J, Rademacher M, Pendziwiat M, Muhle H, Rademacher A, van Baalen A, von Spiczak S, Stephani U, Afawi Z, Korczyn AD, Kanaan M, Canavati C, Kurlemann G, Müller-Schlüter K, Kluger G, Häusler M, Blatt I, Lemke JR, Krey I, Weber YG, Wolking S, Becker F, Hengsbach C, Rau S, Maisch AF, Steinhoff BJ, Schulze-Bonhage A, Schubert-Bast S, Schreiber H, Borggräfe I, Schankin CJ, Mayer T, Korinthenberg R, Brockmann K, Kurlemann G, Dennig D, Madeleyn R, Kälviäinen R, Auvinen P, Saarela A, Linnankivi T, Lehesjoki AE, Rees MI, Chung SK, Pickrell WO, Powell R, Schneider N, Balestrini S, Zagaglia S, Braatz V, Johnson MR, Auce P, Sills GJ, Baum LW, Sham PC, Cherny SS, Lui CH, Barišić N, Delanty N, Doherty CP, Shukralla A, McCormack M, El-Naggar H, Canafoglia L, Franceschetti S, Castellotti B, Granata T, Zara F, Iacomino M, Madia F, Vari MS, Mancardi MM, Salpietro V, Bisulli F, Tinuper P, Licchetta L, Pippucci T, Stipa C, Minardi R, Gambardella A, Labate A, Annesi G, Manna L, Gagliardi M, Parrini E, Mei D, Vetro A, Bianchini C, Montomoli M, Doccini V, Marini C, Suzuki T, Inoue Y, Yamakawa K, Tumiene B, Sadleir LG, King C, Mountier E, Caglayan SH, Arslan M, Yapıcı Z, Yis U, Topaloglu P, Kara B, Turkdogan D, Gundogdu-Eken A, Bebek N, Uğur-İşeri S, Baykan B, Salman B, Haryanyan G, Yücesan E, Kesim Y, Özkara Ç, Poduri A, Shiedley BR, Shain C, Buono RJ, Ferraro TN, Sperling MR, Lo W, Privitera M, French JA, Schachter S, Kuzniecky RI, Devinsky O, Hegde M, Khankhanian P, Helbig KL, Ellis CA, Spalletta G, Piras F, Piras F, Gili T, Ciullo V, Reif A, McQuillin A, Bass N, McIntosh A, Blackwood D, Johnstone M, Palotie A, Pato MT, Pato CN, Bromet EJ, Carvalho CB, Achtyes ED, Azevedo MH, Kotov R, Lehrer DS, Malaspina D, Marder SR, Medeiros H, Morley CP, Perkins DO, Sobell JL, Buckley PF, Macciardi F, Rapaport MH, Knowles JA, Fanous AH, McCarroll SA, Gupta N, Gabriel SB, Daly MJ, Lander ES, Lowenstein DH, Goldstein DB, Lerche H, Berkovic SF, Neale BM. Ultra-Rare Genetic Variation in the Epilepsies: A Whole-Exome Sequencing Study of 17,606 Individuals. Am J Hum Genet 2019; 105:267-282. [PMID: 31327507 PMCID: PMC6698801 DOI: 10.1016/j.ajhg.2019.05.020] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/29/2019] [Indexed: 12/20/2022] Open
Abstract
Sequencing-based studies have identified novel risk genes associated with severe epilepsies and revealed an excess of rare deleterious variation in less-severe forms of epilepsy. To identify the shared and distinct ultra-rare genetic risk factors for different types of epilepsies, we performed a whole-exome sequencing (WES) analysis of 9,170 epilepsy-affected individuals and 8,436 controls of European ancestry. We focused on three phenotypic groups: severe developmental and epileptic encephalopathies (DEEs), genetic generalized epilepsy (GGE), and non-acquired focal epilepsy (NAFE). We observed that compared to controls, individuals with any type of epilepsy carried an excess of ultra-rare, deleterious variants in constrained genes and in genes previously associated with epilepsy; we saw the strongest enrichment in individuals with DEEs and the least strong in individuals with NAFE. Moreover, we found that inhibitory GABAA receptor genes were enriched for missense variants across all three classes of epilepsy, whereas no enrichment was seen in excitatory receptor genes. The larger gene groups for the GABAergic pathway or cation channels also showed a significant mutational burden in DEEs and GGE. Although no single gene surpassed exome-wide significance among individuals with GGE or NAFE, highly constrained genes and genes encoding ion channels were among the lead associations; such genes included CACNA1G, EEF1A2, and GABRG2 for GGE and LGI1, TRIM3, and GABRG2 for NAFE. Our study, the largest epilepsy WES study to date, confirms a convergence in the genetics of severe and less-severe epilepsies associated with ultra-rare coding variation, and it highlights a ubiquitous role for GABAergic inhibition in epilepsy etiology.
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105
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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: 33] [Impact Index Per Article: 6.6] [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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Fitzgerald MP, Fiannacca M, Smith DM, Gertler TS, Gunning B, Syrbe S, Verbeek N, Stamberger H, Weckhuysen S, Ceulemans B, Schoonjans AS, Rossi M, Demarquay G, Lesca G, Olofsson K, Koolen DA, Hornemann F, Baulac S, Rubboli G, Minks KQ, Lee B, Helbig I, Dlugos D, Møller RS, Bearden D. Treatment Responsiveness in KCNT1-Related Epilepsy. Neurotherapeutics 2019; 16:848-857. [PMID: 31054119 PMCID: PMC6694367 DOI: 10.1007/s13311-019-00739-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Pathogenic variants in KCNT1 represent an important cause of treatment-resistant epilepsy, for which an effective therapy has been elusive. Reports about the effectiveness of quinidine, a candidate precision therapy, have been mixed. We sought to evaluate the treatment responsiveness of patients with KCNT1-related epilepsy. We performed an observational study of 43 patients using a collaborative KCNT1 patient registry. We assessed treatment efficacy based upon clinical seizure reduction, side effects of quinidine therapy, and variant-specific responsiveness to treatment. Quinidine treatment resulted in a > 50% seizure reduction in 20% of patients, with rare patients achieving transient seizure freedom. Multiple other therapies demonstrated some success in reducing seizure frequency, including the ketogenic diet and vigabatrin, the latter particularly in patients with epileptic spasms. Patients with the best quinidine response had variants that clustered distal to the NADP domain within the RCK2 domain of the protein. Half of patients did not receive a quinidine trial. In those who did, nearly half did not achieve therapeutic blood levels. More favorable response to quinidine in patients with KCNT1 variants distal to the NADP domain within the RCK2 domain may suggest a variant-specific response.
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O'Donnell-Luria AH, Pais LS, Faundes V, Wood JC, Sveden A, Luria V, Abou Jamra R, Accogli A, Amburgey K, Anderlid BM, Azzarello-Burri S, Basinger AA, Bianchini C, Bird LM, Buchert R, Carre W, Ceulemans S, Charles P, Cox H, Culliton L, Currò A, Demurger F, Dowling JJ, Duban-Bedu B, Dubourg C, Eiset SE, Escobar LF, Ferrarini A, Haack TB, Hashim M, Heide S, Helbig KL, Helbig I, Heredia R, Héron D, Isidor B, Jonasson AR, Joset P, Keren B, Kok F, Kroes HY, Lavillaureix A, Lu X, Maas SM, Maegawa GHB, Marcelis CLM, Mark PR, Masruha MR, McLaughlin HM, McWalter K, Melchinger EU, Mercimek-Andrews S, Nava C, Pendziwiat M, Person R, Ramelli GP, Ramos LLP, Rauch A, Reavey C, Renieri A, Rieß A, Sanchez-Valle A, Sattar S, Saunders C, Schwarz N, Smol T, Srour M, Steindl K, Syrbe S, Taylor JC, Telegrafi A, Thiffault I, Trauner DA, van der Linden H, van Koningsbruggen S, Villard L, Vogel I, Vogt J, Weber YG, Wentzensen IM, Widjaja E, Zak J, Baxter S, Banka S, Rodan LH. Heterozygous Variants in KMT2E Cause a Spectrum of Neurodevelopmental Disorders and Epilepsy. Am J Hum Genet 2019; 104:1210-1222. [PMID: 31079897 PMCID: PMC6556837 DOI: 10.1016/j.ajhg.2019.03.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/21/2019] [Indexed: 01/22/2023] Open
Abstract
We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities.
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108
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Helbig I, Lopez-Hernandez T, Shor O, Galer P, Ganesan S, Pendziwiat M, Rademacher A, Ellis CA, Hümpfer N, Schwarz N, Seiffert S, Peeden J, Shen J, Štěrbová K, Hammer TB, Møller RS, Shinde DN, Tang S, Smith L, Poduri A, Krause R, Benninger F, Helbig KL, Haucke V, Weber YG. A Recurrent Missense Variant in AP2M1 Impairs Clathrin-Mediated Endocytosis and Causes Developmental and Epileptic Encephalopathy. Am J Hum Genet 2019; 104:1060-1072. [PMID: 31104773 PMCID: PMC6556875 DOI: 10.1016/j.ajhg.2019.04.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 03/29/2019] [Indexed: 11/17/2022] Open
Abstract
The developmental and epileptic encephalopathies (DEEs) are heterogeneous disorders with a strong genetic contribution, but the underlying genetic etiology remains unknown in a significant proportion of individuals. To explore whether statistical support for genetic etiologies can be generated on the basis of phenotypic features, we analyzed whole-exome sequencing data and phenotypic similarities by using Human Phenotype Ontology (HPO) in 314 individuals with DEEs. We identified a de novo c.508C>T (p.Arg170Trp) variant in AP2M1 in two individuals with a phenotypic similarity that was higher than expected by chance (p = 0.003) and a phenotype related to epilepsy with myoclonic-atonic seizures. We subsequently found the same de novo variant in two individuals with neurodevelopmental disorders and generalized epilepsy in a cohort of 2,310 individuals who underwent diagnostic whole-exome sequencing. AP2M1 encodes the μ-subunit of the adaptor protein complex 2 (AP-2), which is involved in clathrin-mediated endocytosis (CME) and synaptic vesicle recycling. Modeling of protein dynamics indicated that the p.Arg170Trp variant impairs the conformational activation and thermodynamic entropy of the AP-2 complex. Functional complementation of both the μ-subunit carrying the p.Arg170Trp variant in human cells and astrocytes derived from AP-2μ conditional knockout mice revealed a significant impairment of CME of transferrin. In contrast, stability, expression levels, membrane recruitment, and localization were not impaired, suggesting a functional alteration of the AP-2 complex as the underlying disease mechanism. We establish a recurrent pathogenic variant in AP2M1 as a cause of DEEs with distinct phenotypic features, and we implicate dysfunction of the early steps of endocytosis as a disease mechanism in epilepsy.
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Canavati C, Klein KM, Afawi Z, Pendziwiat M, Abu Rayyan A, Kamal L, Zahdeh F, Qaysia I, Helbig I, Kanaan M. Inclusion of hemimegalencephaly into the phenotypic spectrum of NPRL3 pathogenic variants in familial focal epilepsy with variable foci. Epilepsia 2019; 60:e67-e73. [PMID: 31111464 DOI: 10.1111/epi.15665] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/21/2019] [Accepted: 04/25/2019] [Indexed: 01/14/2023]
Abstract
Despite tremendous progress through next generation sequencing technologies, familial focal epilepsies are insufficiently understood. We sought to identify the genetic basis in multiplex Palestinian families with familial focal epilepsy with variable foci (FFEVF). Family I with 10 affected individuals and Family II with five affected individuals underwent detailed phenotyping over three generations. The phenotypic spectrum of the two families varied from nonlesional focal epilepsy including nocturnal frontal lobe epilepsy to severe structural epilepsy due to hemimegalencephaly. Whole-exome sequencing and single nucleotide polymorphism array analysis revealed pathogenic variants in NPRL3 in each family, a partial ~38-kb deletion encompassing eight exons (exons 8-15) and the 3'-untranslated region of the NPRL3 gene in Family I, and a de novo nonsense variant c.1063C>T, p.Gln355* in Family II. Furthermore, we identified a truncating variant in the PDCD10 gene in addition to the NPRL3 variant in a patient with focal epilepsy from Family I. The individual also had developmental delay and multiple cerebral cavernomas, possibly demonstrating a digenic contribution to the individual's phenotype. Our results implicate the association of NPRL3 with hemimegalencephaly, expanding the phenotypic spectrum of NPRL3 in FFEVF and underlining that partial deletions are part of the genotypic spectrum of NPRL3 variants.
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110
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Heyne HO, Artomov M, Battke F, Bianchini C, Smith DR, Liebmann N, Tadigotla V, Stanley CM, Lal D, Rehm H, Lerche H, Daly MJ, Helbig I, Biskup S, Weber YG, Lemke JR. Targeted gene sequencing in 6994 individuals with neurodevelopmental disorder with epilepsy. Genet Med 2019; 21:2496-2503. [DOI: 10.1038/s41436-019-0531-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/19/2019] [Indexed: 12/16/2022] Open
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111
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Bayat A, Knaus A, Juul AW, Dukic D, Gardella E, Charzewska A, Clement E, Hjalgrim H, Hoffman-Zacharska D, Horn D, Horton R, Hurst JA, Josifova D, Larsen LHG, Lascelles K, Obersztyn E, Pagnamenta A, Pal DK, Pendziwiat M, Ryten M, Taylor J, Vogt J, Weber Y, Krawitz PM, Helbig I, Kini U, Møller RS. PIGT-CDG, a disorder of the glycosylphosphatidylinositol anchor: description of 13 novel patients and expansion of the clinical characteristics. Genet Med 2019; 21:2216-2223. [DOI: 10.1038/s41436-019-0512-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/25/2019] [Indexed: 12/20/2022] Open
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112
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Johannesen KM, Gardella E, Encinas AC, Lehesjoki A, Linnankivi T, Petersen MB, Lund ICB, Blichfeldt S, Miranda MJ, Pal DK, Lascelles K, Procopis P, Orsini A, Bonuccelli A, Giacomini T, Helbig I, Fenger CD, Sisodiya SM, Hernandez‐Hernandez L, Krithika S, Rumple M, Masnada S, Valente M, Cereda C, Giordano L, Accorsi P, Bürki SE, Mancardi M, Korff C, Guerrini R, Spiczak S, Hoffman‐Zacharska D, Mazurczak T, Coppola A, Buono S, Vecchi M, Hammer MF, Varesio C, Veggiotti P, Lal D, Brünger T, Zara F, Striano P, Rubboli G, Møller RS. The spectrum of intermediate
SCN
8A
‐related epilepsy. Epilepsia 2019; 60:830-844. [DOI: 10.1111/epi.14705] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/07/2019] [Accepted: 03/07/2019] [Indexed: 01/06/2023]
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Taylor DM, Aronow BJ, Tan K, Bernt K, Salomonis N, Greene CS, Frolova A, Henrickson SE, Wells A, Pei L, Jaiswal JK, Whitsett J, Hamilton KE, MacParland SA, Kelsen J, Heuckeroth RO, Potter SS, Vella LA, Terry NA, Ghanem LR, Kennedy BC, Helbig I, Sullivan KE, Castelo-Soccio L, Kreigstein A, Herse F, Nawijn MC, Koppelman GH, Haendel M, Harris NL, Rokita JL, Zhang Y, Regev A, Rozenblatt-Rosen O, Rood JE, Tickle TL, Vento-Tormo R, Alimohamed S, Lek M, Mar JC, Loomes KM, Barrett DM, Uapinyoying P, Beggs AH, Agrawal PB, Chen YW, Muir AB, Garmire LX, Snapper SB, Nazarian J, Seeholzer SH, Fazelinia H, Singh LN, Faryabi RB, Raman P, Dawany N, Xie HM, Devkota B, Diskin SJ, Anderson SA, Rappaport EF, Peranteau W, Wikenheiser-Brokamp KA, Teichmann S, Wallace D, Peng T, Ding YY, Kim MS, Xing Y, Kong SW, Bönnemann CG, Mandl KD, White PS. The Pediatric Cell Atlas: Defining the Growth Phase of Human Development at Single-Cell Resolution. Dev Cell 2019; 49:10-29. [PMID: 30930166 PMCID: PMC6616346 DOI: 10.1016/j.devcel.2019.03.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 02/11/2019] [Accepted: 03/01/2019] [Indexed: 12/15/2022]
Abstract
Single-cell gene expression analyses of mammalian tissues have uncovered profound stage-specific molecular regulatory phenomena that have changed the understanding of unique cell types and signaling pathways critical for lineage determination, morphogenesis, and growth. We discuss here the case for a Pediatric Cell Atlas as part of the Human Cell Atlas consortium to provide single-cell profiles and spatial characterization of gene expression across human tissues and organs. Such data will complement adult and developmentally focused HCA projects to provide a rich cytogenomic framework for understanding not only pediatric health and disease but also environmental and genetic impacts across the human lifespan.
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Balciuniene J, DeChene ET, Akgumus G, Romasko EJ, Cao K, Dubbs HA, Mulchandani S, Spinner NB, Conlin LK, Marsh ED, Goldberg E, Helbig I, Sarmady M, Abou Tayoun A. Use of a Dynamic Genetic Testing Approach for Childhood-Onset Epilepsy. JAMA Netw Open 2019; 2:e192129. [PMID: 30977854 PMCID: PMC6481455 DOI: 10.1001/jamanetworkopen.2019.2129] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
IMPORTANCE Although genetic testing is important for bringing precision medicine to children with epilepsy, it is unclear what genetic testing strategy is best in maximizing diagnostic yield. OBJECTIVES To evaluate the diagnostic yield of an exome-based gene panel for childhood epilepsy and discuss the value of follow-up testing. DESIGN, SETTING, AND PARTICIPANTS A case series study was conducted on data from clinical genetic testing at Children's Hospital of Philadelphia was conducted from September 26, 2016, to January 8, 2018. Initial testing targeted 100 curated epilepsy genes for sequence and copy number analysis in 151 children with idiopathic epilepsy referred consecutively by neurologists. Additional genetic testing options were offered afterward. EXPOSURES Clinical genetic testing. MAIN OUTCOMES AND MEASURES Molecular diagnostic findings. RESULTS Of 151 patients (84 boys [55.6%]; median age, 4.2 years [interquartile range, 1.4-8.7 years]), 16 children (10.6%; 95% CI, 6%-16%) received a diagnosis after initial panel analysis. Parental testing for 15 probands with inconclusive results revealed de novo variants in 7 individuals (46.7%), resulting in an overall diagnostic yield of 15.3% (23 of 151; 95% CI, 9%-21%). Twelve probands with nondiagnostic panel findings were reflexed to exome sequencing, and 4 were diagnostic (33.3%; 95% CI, 6%-61%), raising the overall diagnostic yield to 17.9% (27 of 151; 95% CI, 12%-24%). The yield was highest (17 of 44 [38.6%; 95% CI, 24%-53%]) among probands with epilepsy onset in infancy (age, 1-12 months). Panel diagnostic findings involved 16 genes: SCN1A (n = 4), PRRT2 (n = 3), STXBP1 (n = 2), IQSEC2 (n = 2), ATP1A2, ATP1A3, CACNA1A, GABRA1, KCNQ2, KCNT1, SCN2A, SCN8A, DEPDC5, TPP1, PCDH19, and UBE3A (all n = 1). Exome sequencing analysis identified 4 genes: SMC1A, SETBP1, NR2F1, and TRIT1. For the remaining 124 patients, analysis of 13 additional genes implicated in epilepsy since the panel was launched in 2016 revealed promising findings in 6 patients. CONCLUSIONS AND RELEVANCE Exome-based targeted panels appear to enable rapid analysis of a preselected set of genes while retaining flexibility in gene content. Successive genetic workup should include parental testing of select probands with inconclusive results and reflex to whole-exome trio analysis for the remaining nondiagnostic cases. Periodic reanalysis is needed to capture information in newly identified disease genes.
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Helbig KL, Lauerer RJ, Bahr JC, Souza IA, Myers CT, Uysal B, Schwarz N, Gandini MA, Huang S, Keren B, Mignot C, Afenjar A, Billette de Villemeur T, Héron D, Nava C, Valence S, Buratti J, Fagerberg CR, Soerensen KP, Kibaek M, Kamsteeg EJ, Koolen DA, Gunning B, Schelhaas HJ, Kruer MC, Fox J, Bakhtiari S, Jarrar R, Padilla-Lopez S, Lindstrom K, Jin SC, Zeng X, Bilguvar K, Papavasileiou A, Xing Q, Zhu C, Boysen K, Vairo F, Lanpher BC, Klee EW, Tillema JM, Payne ET, Cousin MA, Kruisselbrink TM, Wick MJ, Baker J, Haan E, Smith N, Sadeghpour A, Davis EE, Katsanis N, Corbett MA, MacLennan AH, Gecz J, Biskup S, Goldmann E, Rodan LH, Kichula E, Segal E, Jackson KE, Asamoah A, Dimmock D, McCarrier J, Botto LD, Filloux F, Tvrdik T, Cascino GD, Klingerman S, Neumann C, Wang R, Jacobsen JC, Nolan MA, Snell RG, Lehnert K, Sadleir LG, Anderlid BM, Kvarnung M, Guerrini R, Friez MJ, Lyons MJ, Leonhard J, Kringlen G, Casas K, El Achkar CM, Smith LA, Rotenberg A, Poduri A, Sanchis-Juan A, Carss KJ, Rankin J, Zeman A, Raymond FL, Blyth M, Kerr B, Ruiz K, Urquhart J, Hughes I, Banka S, Hedrich UB, Scheffer IE, Helbig I, Zamponi GW, Lerche H, Mefford HC, Allori A, Angrist M, Ashley P, Bidegain M, Boyd B, Chambers E, Cope H, Cotten CM, Curington T, Davis EE, Ellestad S, Fisher K, French A, Gallentine W, Goldberg R, Hill K, Kansagra S, Katsanis N, Katsanis S, Kurtzberg J, Marcus J, McDonald M, Mikati M, Miller S, Murtha A, Perilla Y, Pizoli C, Purves T, Ross S, Sadeghpour A, Smith E, Wiener J. De Novo Pathogenic Variants in CACNA1E Cause Developmental and Epileptic Encephalopathy with Contractures, Macrocephaly, and Dyskinesias. Am J Hum Genet 2019; 104:562. [PMID: 30849329 DOI: 10.1016/j.ajhg.2019.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Siekierska A, Stamberger H, Deconinck T, Oprescu SN, Partoens M, Zhang Y, Sourbron J, Adriaenssens E, Mullen P, Wiencek P, Hardies K, Lee JS, Giong HK, Distelmaier F, Elpeleg O, Helbig KL, Hersh J, Isikay S, Jordan E, Karaca E, Kecskes A, Lupski JR, Kovacs-Nagy R, May P, Narayanan V, Pendziwiat M, Ramsey K, Rangasamy S, Shinde DN, Spiegel R, Timmerman V, von Spiczak S, Helbig I, Weckhuysen S, Francklyn C, Antonellis A, de Witte P, De Jonghe P. Biallelic VARS variants cause developmental encephalopathy with microcephaly that is recapitulated in vars knockout zebrafish. Nat Commun 2019; 10:708. [PMID: 30755616 PMCID: PMC6372652 DOI: 10.1038/s41467-018-07953-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 10/03/2018] [Indexed: 11/09/2022] Open
Abstract
Aminoacyl tRNA synthetases (ARSs) link specific amino acids with their cognate transfer RNAs in a critical early step of protein translation. Mutations in ARSs have emerged as a cause of recessive, often complex neurological disease traits. Here we report an allelic series consisting of seven novel and two previously reported biallelic variants in valyl-tRNA synthetase (VARS) in ten patients with a developmental encephalopathy with microcephaly, often associated with early-onset epilepsy. In silico, in vitro, and yeast complementation assays demonstrate that the underlying pathomechanism of these mutations is most likely a loss of protein function. Zebrafish modeling accurately recapitulated some of the key neurological disease traits. These results provide both genetic and biological insights into neurodevelopmental disease and pave the way for further in-depth research on ARS related recessive disorders and precision therapies. tRNAs are linked with their cognate amino acid by aminoacyl tRNA synthetases (ARS). Here, the authors report a developmental encephalopathy associated with biallelic VARS variants (valyl-tRNA synthetase) that lead to loss of function, as determined by several in vitro assays and a vars knockout zebrafish model.
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Wolking S, May P, Mei D, Møller RS, Balestrini S, Helbig KL, Altuzarra CD, Chatron N, Kaiwar C, Stöhr K, Widdess-Walsh P, Mendelsohn BA, Numis A, Cilio MR, Van Paesschen W, Svendsen LL, Oates S, Hughes E, Goyal S, Brown K, Sifuentes Saenz M, Dorn T, Muhle H, Pagnamenta AT, Vavoulis DV, Knight SJL, Taylor JC, Canevini MP, Darra F, Gavrilova RH, Powis Z, Tang S, Marquetand J, Armstrong M, McHale D, Klee EW, Kluger GJ, Lowenstein DH, Weckhuysen S, Pal DK, Helbig I, Guerrini R, Thomas RH, Rees MI, Lesca G, Sisodiya SM, Weber YG, Lal D, Marini C, Lerche H, Schubert J. Clinical spectrum of STX1B-related epileptic disorders. Neurology 2019; 92:e1238-e1249. [PMID: 30737342 PMCID: PMC6511102 DOI: 10.1212/wnl.0000000000007089] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 11/04/2018] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE The aim of this study was to expand the spectrum of epilepsy syndromes related to STX1B, encoding the presynaptic protein syntaxin-1B, and establish genotype-phenotype correlations by identifying further disease-related variants. METHODS We used next-generation sequencing in the framework of research projects and diagnostic testing. Clinical data and EEGs were reviewed, including already published cases. To estimate the pathogenicity of the variants, we used established and newly developed in silico prediction tools. RESULTS We describe 17 new variants in STX1B, which are distributed across the whole gene. We discerned 4 different phenotypic groups across the newly identified and previously published patients (49 patients in 23 families): (1) 6 sporadic patients or families (31 affected individuals) with febrile and afebrile seizures with a benign course, generally good drug response, normal development, and without permanent neurologic deficits; (2) 2 patients with genetic generalized epilepsy without febrile seizures and cognitive deficits; (3) 13 patients or families with intractable seizures, developmental regression after seizure onset and additional neuropsychiatric symptoms; (4) 2 patients with focal epilepsy. More often, we found loss-of-function mutations in benign syndromes, whereas missense variants in the SNARE motif of syntaxin-1B were associated with more severe phenotypes. CONCLUSION These data expand the genetic and phenotypic spectrum of STX1B-related epilepsies to a diverse range of epilepsies that span the International League Against Epilepsy classification. Variants in STX1B are protean and contribute to many different epilepsy phenotypes, similar to SCN1A, the most important gene associated with fever-associated epilepsies.
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Carvill GL, Engel KL, Ramamurthy A, Cochran JN, Roovers J, Stamberger H, Lim N, Schneider AL, Hollingsworth G, Holder DH, Regan BM, Lawlor J, Lagae L, Ceulemans B, Bebin EM, Nguyen J, Barsh GS, Weckhuysen S, Meisler M, Berkovic SF, De Jonghe P, Scheffer IE, Myers RM, Cooper GM, Mefford HC, Striano P, Zara F, Helbig I, Møller RS, von Spiczak S, Muhle H, Caglayan H, Sterbova K, Craiu D, Hoffman D, Lehesjoki AE, Selmer K, Depienne C, Lemke J, Marini C, Guerrini R, Neubauer B, Talvik T, Leguern E, de Jonghe P, Weckhuysen S. Aberrant Inclusion of a Poison Exon Causes Dravet Syndrome and Related SCN1A-Associated Genetic Epilepsies. Am J Hum Genet 2018; 103:1022-1029. [PMID: 30526861 DOI: 10.1016/j.ajhg.2018.10.023] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/25/2018] [Indexed: 12/30/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are a group of severe epilepsies characterized by refractory seizures and developmental impairment. Sequencing approaches have identified causal genetic variants in only about 50% of individuals with DEEs.1-3 This suggests that unknown genetic etiologies exist, potentially in the ∼98% of human genomes not covered by exome sequencing (ES). Here we describe seven likely pathogenic variants in regions outside of the annotated coding exons of the most frequently implicated epilepsy gene, SCN1A, encoding the alpha-1 sodium channel subunit. We provide evidence that five of these variants promote inclusion of a "poison" exon that leads to reduced amounts of full-length SCN1A protein. This mechanism is likely to be broadly relevant to human disease; transcriptome studies have revealed hundreds of poison exons,4,5 including some present within genes encoding other sodium channels and in genes involved in neurodevelopment more broadly.6 Future research on the mechanisms that govern neuronal-specific splicing behavior might allow researchers to co-opt this system for RNA therapeutics.
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Helbig KL, Lauerer RJ, Bahr JC, Souza IA, Myers CT, Uysal B, Schwarz N, Gandini MA, Huang S, Keren B, Mignot C, Afenjar A, Billette de Villemeur T, Héron D, Nava C, Valence S, Buratti J, Fagerberg CR, Soerensen KP, Kibaek M, Kamsteeg EJ, Koolen DA, Gunning B, Schelhaas HJ, Kruer MC, Fox J, Bakhtiari S, Jarrar R, Padilla-Lopez S, Lindstrom K, Jin SC, Zeng X, Bilguvar K, Papavasileiou A, Xing Q, Zhu C, Boysen K, Vairo F, Lanpher BC, Klee EW, Tillema JM, Payne ET, Cousin MA, Kruisselbrink TM, Wick MJ, Baker J, Haan E, Smith N, Sadeghpour A, Davis EE, Katsanis N, Corbett MA, MacLennan AH, Gecz J, Biskup S, Goldmann E, Rodan LH, Kichula E, Segal E, Jackson KE, Asamoah A, Dimmock D, McCarrier J, Botto LD, Filloux F, Tvrdik T, Cascino GD, Klingerman S, Neumann C, Wang R, Jacobsen JC, Nolan MA, Snell RG, Lehnert K, Sadleir LG, Anderlid BM, Kvarnung M, Guerrini R, Friez MJ, Lyons MJ, Leonhard J, Kringlen G, Casas K, El Achkar CM, Smith LA, Rotenberg A, Poduri A, Sanchis-Juan A, Carss KJ, Rankin J, Zeman A, Raymond FL, Blyth M, Kerr B, Ruiz K, Urquhart J, Hughes I, Banka S, Hedrich UB, Scheffer IE, Helbig I, Zamponi GW, Lerche H, Mefford HC, Allori A, Angrist M, Ashley P, Bidegain M, Boyd B, Chambers E, Cope H, Cotten CM, Curington T, Davis EE, Ellestad S, Fisher K, French A, Gallentine W, Goldberg R, Hill K, Kansagra S, Katsanis N, Katsanis S, Kurtzberg J, Marcus J, McDonald M, Mikati M, Miller S, Murtha A, Perilla Y, Pizoli C, Purves T, Ross S, Sadeghpour A, Smith E, Wiener J. De Novo Pathogenic Variants in CACNA1E Cause Developmental and Epileptic Encephalopathy with Contractures, Macrocephaly, and Dyskinesias. Am J Hum Genet 2018; 103:666-678. [PMID: 30343943 DOI: 10.1016/j.ajhg.2018.09.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/17/2018] [Indexed: 12/27/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are severe neurodevelopmental disorders often beginning in infancy or early childhood that are characterized by intractable seizures, abundant epileptiform activity on EEG, and developmental impairment or regression. CACNA1E is highly expressed in the central nervous system and encodes the α1-subunit of the voltage-gated CaV2.3 channel, which conducts high voltage-activated R-type calcium currents that initiate synaptic transmission. Using next-generation sequencing techniques, we identified de novo CACNA1E variants in 30 individuals with DEE, characterized by refractory infantile-onset seizures, severe hypotonia, and profound developmental impairment, often with congenital contractures, macrocephaly, hyperkinetic movement disorders, and early death. Most of the 14, partially recurring, variants cluster within the cytoplasmic ends of all four S6 segments, which form the presumed CaV2.3 channel activation gate. Functional analysis of several S6 variants revealed consistent gain-of-function effects comprising facilitated voltage-dependent activation and slowed inactivation. Another variant located in the domain II S4-S5 linker results in facilitated activation and increased current density. Five participants achieved seizure freedom on the anti-epileptic drug topiramate, which blocks R-type calcium channels. We establish pathogenic variants in CACNA1E as a cause of DEEs and suggest facilitated R-type calcium currents as a disease mechanism for human epilepsy and developmental disorders.
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Holze N, Baalen AV, Stephani U, Helbig I, Muhle H. Variants in the ATP1A3 Gene Mutations within Severe Apnea Starting in Early Infancy: An Observational Study of Two Cases with a Possible Relation to Epileptic Activity. Neuropediatrics 2018; 49:342-346. [PMID: 29801192 DOI: 10.1055/s-0038-1653978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Mutations in the ATP1A3 gene are known to cause alternating hemiplegia of childhood (AHC) and rapid-onset dystonia parkinsonism (RDP). Both conditions are childhood-onset neurological disorders with distinct symptoms and different times of onset. ATP1A3 has also been associated with CAPOS syndrome (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss). Within the various ATP1A3-related neurological syndromes, a specific genotype-phenotype correlation is starting to emerge. Several mutations such as the relatively common p.E815K pathogenic variant have been shown to strongly correlate with AHC, while others may cause both AHC and RDP. A significant subset of patients with AHC and RDP are reported to have epileptic seizures. Even though detailed clinical descriptions of seizures in childhood are rare, seizures involving apneic events seem to be frequent in ATP1A3-related neurological disorders. Here, we describe two children with unexplained severe apnea beginning around the first year of life and pathogenic variants in ATP1A3. We hypothesize that the symptoms are early-onset autonomic seizures related to the underlying pathogenic ATP1A3 variants.
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Dines JN, Golden-Grant K, LaCroix A, Muir AM, Cintrón DL, McWalter K, Cho MT, Sun A, Merritt JL, Thies J, Niyazov D, Burton B, Kim K, Fleming L, Westman R, Karachunski P, Dalton J, Basinger A, Ficicioglu C, Helbig I, Pendziwiat M, Muhle H, Helbig KL, Caliebe A, Santer R, Becker K, Suchy S, Douglas G, Millan F, Begtrup A, Monaghan KG, Mefford HC. TANGO2: expanding the clinical phenotype and spectrum of pathogenic variants. Genet Med 2018; 21:601-607. [PMID: 30245509 PMCID: PMC6752277 DOI: 10.1038/s41436-018-0137-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/05/2018] [Indexed: 12/22/2022] Open
Abstract
Purpose TANGO2-related disorders were first described in 2016 and prior to this publication, only 15 individuals with TANGO2-related disorder were described in the literature. Primary features include metabolic crisis with rhabdomyolysis, encephalopathy, intellectual disability, seizures, and cardiac arrhythmias. We assess whether genotype and phenotype of TANGO2-related disorder has expanded since the initial discovery and determine the efficacy of exome sequencing (ES) as a diagnostic tool for detecting variants. Methods We present a series of 14 individuals from 11 unrelated families with complex medical and developmental histories, in whom ES or microarray identified compound heterozygous or homozygous variants in TANGO2. Results The initial presentation of patients with TANGO2-related disorders can be variable, including primarily neurological presentations. We expand the phenotype and genotype for TANGO2, highlighting the variability of the disorder. Conclusion TANGO2-related disorders can have a more diverse clinical presentation than previously anticipated. We illustrate the utility of routine ES data reanalysis whereby discovery of novel disease genes can lead to a diagnosis in previously unsolved cases and the need for additional copy-number variation analysis when ES is performed.
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Mignot C, McMahon AC, Bar C, Campeau PM, Davidson C, Buratti J, Nava C, Jacquemont ML, Tallot M, Milh M, Edery P, Marzin P, Barcia G, Barnerias C, Besmond C, Bienvenu T, Bruel AL, Brunga L, Ceulemans B, Coubes C, Cristancho AG, Cunningham F, Dehouck MB, Donner EJ, Duban-Bedu B, Dubourg C, Gardella E, Gauthier J, Geneviève D, Gobin-Limballe S, Goldberg EM, Hagebeuk E, Hamdan FF, Hančárová M, Hubert L, Ioos C, Ichikawa S, Janssens S, Journel H, Kaminska A, Keren B, Koopmans M, Lacoste C, Laššuthová P, Lederer D, Lehalle D, Marjanovic D, Métreau J, Michaud JL, Miller K, Minassian BA, Morales J, Moutard ML, Munnich A, Ortiz-Gonzalez XR, Pinard JM, Prchalová D, Putoux A, Quelin C, Rosen AR, Roume J, Rossignol E, Simon MEH, Smol T, Shur N, Shelihan I, Štěrbová K, Vyhnálková E, Vilain C, Soblet J, Smits G, Yang SP, van der Smagt JJ, van Hasselt PM, van Kempen M, Weckhuysen S, Helbig I, Villard L, Héron D, Koeleman B, Møller RS, Lesca G, Helbig KL, Nabbout R, Verbeek NE, Depienne C. IQSEC2-related encephalopathy in males and females: a comparative study including 37 novel patients. Genet Med 2018; 21:837-849. [PMID: 30206421 PMCID: PMC6752297 DOI: 10.1038/s41436-018-0268-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/31/2018] [Indexed: 12/19/2022] Open
Abstract
Purpose Variants in IQSEC2, escaping X inactivation, cause X-linked intellectual disability with frequent epilepsy in males and females. We aimed to investigate sex-specific differences. Methods We collected the data of 37 unpublished patients (18 males and 19 females) with IQSEC2 pathogenic variants and 5 individuals with variants of unknown significance and reviewed published variants. We compared variant types and phenotypes in males and females and performed an analysis of IQSEC2 isoforms. Results IQSEC2 pathogenic variants mainly led to premature truncation and were scattered throughout the longest brain-specific isoform, encoding the synaptic IQSEC2/BRAG1 protein. Variants occurred de novo in females but were either de novo (2/3) or inherited (1/3) in males, with missense variants being predominantly inherited. Developmental delay and intellectual disability were overall more severe in males than in females. Likewise, seizures were more frequently observed and intractable, and started earlier in males than in females. No correlation was observed between the age at seizure onset and severity of intellectual disability or resistance to antiepileptic treatments. Conclusion This study provides a comprehensive overview of IQSEC2-related encephalopathy in males and females, and suggests that an accurate dosage of IQSEC2 at the synapse is crucial during normal brain development.
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Gardella E, Marini C, Trivisano M, Fitzgerald MP, Alber M, Howell KB, Darra F, Siliquini S, Bölsterli BK, Masnada S, Pichiecchio A, Johannesen KM, Jepsen B, Fontana E, Anibaldi G, Russo S, Cogliati F, Montomoli M, Specchio N, Rubboli G, Veggiotti P, Beniczky S, Wolff M, Helbig I, Vigevano F, Scheffer IE, Guerrini R, Møller RS. The phenotype of SCN8A developmental and epileptic encephalopathy. Neurology 2018; 91:e1112-e1124. [DOI: 10.1212/wnl.0000000000006199] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 06/20/2018] [Indexed: 12/20/2022] Open
Abstract
ObjectiveTo delineate the electroclinical features of SCN8A infantile developmental and epileptic encephalopathy (EIEE13, OMIM #614558).MethodsTwenty-two patients, aged 19 months to 22 years, underwent electroclinical assessment.ResultsSixteen of 22 patients had mildly delayed development since birth. Drug-resistant epilepsy started at a median age of 4 months, followed by developmental slowing, pyramidal/extrapyramidal signs (22/22), movement disorders (12/22), cortical blindness (17/22), sialorrhea, and severe gastrointestinal symptoms (15/22), worsening during early childhood and plateauing at age 5 to 9 years. Death occurred in 4 children, following extreme neurologic deterioration, at 22 months to 5.5 years. Nonconvulsive status epilepticus recurred in 14 of 22 patients. The most effective antiepileptic drugs were oxcarbazepine, carbamazepine, phenytoin, and benzodiazepines. EEG showed background deterioration, epileptiform abnormalities with a temporo-occipital predominance, and posterior delta/beta activity correlating with visual impairment. Video-EEG documented focal seizures (FS) (22/22), spasm-like episodes (8/22), cortical myoclonus (8/22), and myoclonic absences (1/22). FS typically clustered and were prolonged (<20 minutes) with (1) cyanosis, hypomotor, and vegetative semiology, sometimes unnoticed, followed by (2) tonic-vibratory and (3) (hemi)-clonic manifestations ± evolution to a bilateral tonic-clonic seizure. FS had posterior-temporal/occipital onset, slowly spreading and sometimes migrating between hemispheres. Brain MRI showed progressive parenchymal atrophy and restriction of the optic radiations.Conclusions:SCN8A developmental and epileptic encephalopathy has strikingly consistent electroclinical features, suggesting a global progressive brain dysfunction primarily affecting the temporo-occipital regions. Both uncontrolled epilepsy and developmental compromise contribute to the profound impairment (increasing risk of death) during early childhood, but stabilization occurs in late childhood.
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Goldberg EM, Helbig I. Reply to “Recurrent SCN3A
p.Ile875Thr variant in patients with polymicrogyria”. Ann Neurol 2018; 84:161. [DOI: 10.1002/ana.25254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/16/2018] [Indexed: 11/06/2022]
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Johannesen KM, Gardella E, Scheffer I, Howell K, Smith DM, Helbig I, Møller RS, Rubboli G. Early mortality in SCN8A -related epilepsies. Epilepsy Res 2018; 143:79-81. [DOI: 10.1016/j.eplepsyres.2018.04.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/05/2018] [Accepted: 04/11/2018] [Indexed: 12/13/2022]
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