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Brito F, Lagos C, Cubillos J, Orellana J, Gajardo M, Böhme D, Encina G, Repetto GM. Genomic analysis in Chilean patients with suspected Rett syndrome: keep a broad differential diagnosis. Front Genet 2024; 15:1278198. [PMID: 38566815 PMCID: PMC10986174 DOI: 10.3389/fgene.2024.1278198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction: Rett syndrome (RTT, MIM #312750) is a rare genetic disorder that leads to developmental regression and severe disability and is caused by pathogenic variants in the MECP2 gene. The diagnosis of RTT is based on clinical features and, depending on resources and access, on molecular confirmation. There is scarce information on molecular diagnosis from patients in Latin America, mostly due to limited availability and coverage of genomic testing. This pilot study aimed to implement genomic testing and characterize clinical and molecular findings in a group of Chilean patients with a clinical diagnosis of RTT. Methods: Twenty-eight patients with suspected RTT underwent characterization of phenotypic manifestations and molecular testing using Clinical Exome SolutionTM CES_V2 by SOPHiA Genetics. Data was analyzed using the commercial bioinformatics platform, SOPHiA DDMTM. A virtual panel of 34 genes, including MECP2 and other genes that are in the differential diagnosis of RTT, was used to prioritize initial analyses, followed by evaluation of the complete exome sequence data. Results: Twelve patients (42.8% of participants) had variants in MECP2, of which 11 (39.2%) were interpreted as pathogenic/likely pathogenic (P/LP), thus confirming the diagnosis of RTT in them. Eight additional patients (28.5%) harbored ten variants in nine other genes. Four of these variants were interpreted as P/LP (14.2%) (GRIN2B, MADD, TRPM3 and ZEB2) resulting in alternative neurodevelopmental diagnoses, and six were considered of uncertain significance. No evident candidate variant was found for eight patients. Discussion: This study allowed to reach a diagnosis in half of the participants. The diagnosis of RTT was confirmed in over a third of them, while others were found to have alternative neurodevelopmental disorders. Further evaluation is needed to identify the cause in those with negative or uncertain results. This information is useful for the patients, families, and clinicians to guide clinical management, even more so since the development of novel therapies for RTT. We also show the feasibility of implementing a step-wide approach to genomic testing in a setting with limited resources.
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Affiliation(s)
- Florencia Brito
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Catalina Lagos
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | | | - Joan Orellana
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Mallen Gajardo
- Escuela de Ingeniería, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
| | - Daniela Böhme
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Biosoluciones-UDD, Santiago, Chile
| | | | - Gabriela M. Repetto
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
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Cavirani B, Spagnoli C, Caraffi SG, Cavalli A, Cesaroni CA, Cutillo G, De Giorgis V, Frattini D, Marchetti GB, Masnada S, Peron A, Rizzi S, Varesio C, Spaccini L, Vignoli A, Canevini MP, Veggiotti P, Garavelli L, Fusco C. Genetic Epilepsies and Developmental Epileptic Encephalopathies with Early Onset: A Multicenter Study. Int J Mol Sci 2024; 25:1248. [PMID: 38279250 PMCID: PMC10816990 DOI: 10.3390/ijms25021248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
The genetic causes of epilepsies and developmental and epileptic encephalopathies (DEE) with onset in early childhood are increasingly recognized. Their outcomes vary from benign to severe disability. In this paper, we wished to retrospectively review the clinical, genetic, EEG, neuroimaging, and outcome data of patients experiencing the onset of epilepsy in the first three years of life, diagnosed and followed up in four Italian epilepsy centres (Epilepsy Centre of San Paolo University Hospital in Milan, Child Neurology and Psychiatry Unit of AUSL-IRCCS di Reggio Emilia, Pediatric Neurology Unit of Vittore Buzzi Children's Hospital, Milan, and Child Neurology and Psychiatry Unit, IRCCS Mondino Foundation, Pavia). We included 168 patients (104 with monogenic conditions, 45 with copy number variations (CNVs) or chromosomal abnormalities, and 19 with variants of unknown significance), who had been followed up for a mean of 14.75 years. We found a high occurrence of generalized seizures at onset, drug resistance, abnormal neurological examination, global developmental delay and intellectual disability, and behavioural and psychiatric comorbidities. We also documented differing presentations between monogenic issues versus CNVs and chromosomal conditions, as well as atypical/rare phenotypes. Genetic early-childhood-onset epilepsies and DEE show a very wide phenotypic and genotypic spectrum, with a high risk of complex neurological and neuropsychiatric phenotypes.
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Affiliation(s)
- Benedetta Cavirani
- Child Neuropsychiatry Unit, Azienda USL di Parma, 43121 Parma, Italy;
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Carlotta Spagnoli
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Stefano Giuseppe Caraffi
- Medical Genetics Unit, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy (L.G.)
| | - Anna Cavalli
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Carlo Alberto Cesaroni
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Gianni Cutillo
- Pediatric Neurology Unit, Department of Pediatric Neurology, Buzzi Children’s Hospital, 20154 Milan, Italy; (G.C.); (S.M.); (P.V.)
| | - Valentina De Giorgis
- Department of Brain and Behavioural Sciences, University of Pavia, 27100 Pavia, Italy; (V.D.G.); (C.V.)
- Department of Child Neurology and Psychiatriy, IRCCS Mondino Foundation, ERN-Epicare, 27100 Pavia, Italy
| | - Daniele Frattini
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Giulia Bruna Marchetti
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy;
| | - Silvia Masnada
- Pediatric Neurology Unit, Department of Pediatric Neurology, Buzzi Children’s Hospital, 20154 Milan, Italy; (G.C.); (S.M.); (P.V.)
| | - Angela Peron
- Medical Genetics, Meyer Children’s Hospital IRCCS, 50139 Florence, Italy;
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, Università degli Studi di Firenze, 50121 Florence, Italy
- Medical Genetics, ASST Santi Paolo e Carlo, San Paolo Hospital, 20142 Milan, Italy
| | - Susanna Rizzi
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
| | - Costanza Varesio
- Department of Brain and Behavioural Sciences, University of Pavia, 27100 Pavia, Italy; (V.D.G.); (C.V.)
- Department of Child Neurology and Psychiatriy, IRCCS Mondino Foundation, ERN-Epicare, 27100 Pavia, Italy
| | - Luigina Spaccini
- Clinical Genetics Unit, Department of Obstetrics and Gynecology, V. Buzzi Children’s Hospital, University of Milan, 20157 Milan, Italy;
| | - Aglaia Vignoli
- Child Neuropsychiatry Unit-Epilepsy Center, ASST Santi Paolo e Carlo, San Paolo Hospital, 20142 Milan, Italy; (A.V.); (M.P.C.)
- Department of Health Sciences, University of Milan, 20157 Milan, Italy
| | - Maria Paola Canevini
- Child Neuropsychiatry Unit-Epilepsy Center, ASST Santi Paolo e Carlo, San Paolo Hospital, 20142 Milan, Italy; (A.V.); (M.P.C.)
- Department of Health Sciences, University of Milan, 20157 Milan, Italy
| | - Pierangelo Veggiotti
- Pediatric Neurology Unit, Department of Pediatric Neurology, Buzzi Children’s Hospital, 20154 Milan, Italy; (G.C.); (S.M.); (P.V.)
- Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
| | - Livia Garavelli
- Medical Genetics Unit, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy (L.G.)
| | - Carlo Fusco
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; (A.C.); (C.A.C.); (D.F.); (S.R.); (C.F.)
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Freibauer A, Wohlleben M, Boelman C. STXBP1-Related Disorders: Clinical Presentation, Molecular Function, Treatment, and Future Directions. Genes (Basel) 2023; 14:2179. [PMID: 38137001 PMCID: PMC10742812 DOI: 10.3390/genes14122179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 11/27/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
In recent years, the affordability and availability of genetic testing have led to its increased use in clinical care. The increased frequency of testing has led to STXBP1 variants being identified as one of the more common variants associated with neurological disorders. In this review, we aim to summarize the common clinical phenotypes associated with STXBP1 pathogenic variants, provide an overview of their known natural history, and discuss current research into the genotype to phenotype correlation. We will also provide an overview of the suspected normal function of the STXBP1-encoded Munc18-1 protein, animal models, and experimental techniques that have been developed to study its function and use this information to try to explain the diverse phenotypes associated with STXBP1-related disorders. Finally, we will explore current therapies for STXBP1 disorders, including an overview of treatment goals for STXBP1-related disorders, a discussion of the current evidence for therapies, and future directions of personalized medications for STXBP1-related disorders.
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Affiliation(s)
- Alexander Freibauer
- Division of Neurology, BC Children’s Hospital, Vancouver, BC V6H 3N1, Canada;
- Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Mikayla Wohlleben
- Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Cyrus Boelman
- Division of Neurology, BC Children’s Hospital, Vancouver, BC V6H 3N1, Canada;
- Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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4
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Frankel E, Podder A, Sharifi M, Pillai R, Belnap N, Ramsey K, Dodson J, Venugopal P, Brzezinski M, Llaci L, Gerald B, Mills G, Sanchez-Castillo M, Balak CD, Szelinger S, Jepsen WM, Siniard AL, Richholt R, Naymik M, Schrauwen I, Craig DW, Piras IS, Huentelman MJ, Schork NJ, Narayanan V, Rangasamy S. Genetic and Protein Network Underlying the Convergence of Rett-Syndrome-like (RTT-L) Phenotype in Neurodevelopmental Disorders. Cells 2023; 12:1437. [PMID: 37408271 DOI: 10.3390/cells12101437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/20/2023] [Accepted: 04/29/2023] [Indexed: 07/07/2023] Open
Abstract
Mutations of the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2) cause classical forms of Rett syndrome (RTT) in girls. A subset of patients who are recognized to have an overlapping neurological phenotype with RTT but are lacking a mutation in a gene that causes classical or atypical RTT can be described as having a 'Rett-syndrome-like phenotype (RTT-L). Here, we report eight patients from our cohort diagnosed as having RTT-L who carry mutations in genes unrelated to RTT. We annotated the list of genes associated with RTT-L from our patient cohort, considered them in the light of peer-reviewed articles on the genetics of RTT-L, and constructed an integrated protein-protein interaction network (PPIN) consisting of 2871 interactions connecting 2192 neighboring proteins among RTT- and RTT-L-associated genes. Functional enrichment analysis of RTT and RTT-L genes identified a number of intuitive biological processes. We also identified transcription factors (TFs) whose binding sites are common across the set of RTT and RTT-L genes and appear as important regulatory motifs for them. Investigation of the most significant over-represented pathway analysis suggests that HDAC1 and CHD4 likely play a central role in the interactome between RTT and RTT-L genes.
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Affiliation(s)
- Eric Frankel
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Avijit Podder
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Megan Sharifi
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Roshan Pillai
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Newell Belnap
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Julius Dodson
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Pooja Venugopal
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Molly Brzezinski
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Lorida Llaci
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Brittany Gerald
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Gabrielle Mills
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Meredith Sanchez-Castillo
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Chris D Balak
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Szabolcs Szelinger
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Wayne M Jepsen
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ashley L Siniard
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ryan Richholt
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Marcus Naymik
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
| | - David W Craig
- Department of Translational Genomics, University of Southern California, Los Angeles, CA 90033, USA
| | - Ignazio S Piras
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Matthew J Huentelman
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Nicholas J Schork
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Vinodh Narayanan
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Sampathkumar Rangasamy
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
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5
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Hernandez CC, Shen Y, Hu N, Shen W, Narayanan V, Ramsey K, He W, Zou L, Macdonald RL. GABRG2 Variants Associated with Febrile Seizures. Biomolecules 2023; 13:414. [PMID: 36979350 PMCID: PMC10046037 DOI: 10.3390/biom13030414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Febrile seizures (FS) are the most common form of epilepsy in children between six months and five years of age. FS is a self-limited type of fever-related seizure. However, complicated prolonged FS can lead to complex partial epilepsy. We found that among the GABAA receptor subunit (GABR) genes, most variants associated with FS are harbored in the γ2 subunit (GABRG2). Here, we characterized the effects of eight variants in the GABAA receptor γ2 subunit on receptor biogenesis and channel function. Two-thirds of the GABRG2 variants followed the expected autosomal dominant inheritance in FS and occurred as missense and nonsense variants. The remaining one-third appeared as de novo in the affected probands and occurred only as missense variants. The loss of GABAA receptor function and dominant negative effect on GABAA receptor biogenesis likely caused the FS phenotype. In general, variants in the GABRG2 result in a broad spectrum of phenotypic severity, ranging from asymptomatic, FS, genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome individuals. The data presented here support the link between FS, epilepsy, and GABRG2 variants, shedding light on the relationship between the variant topological occurrence and disease severity.
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Affiliation(s)
- Ciria C. Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yanwen Shen
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Wen He
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Liping Zou
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Robert L. Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Exploring the Genetic Causality of Discordant Phenotypes in Familial Apparently Balanced Translocation Cases Using Whole Exome Sequencing. Genes (Basel) 2022; 14:genes14010082. [PMID: 36672823 PMCID: PMC9859009 DOI: 10.3390/genes14010082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Familial apparently balanced translocations (ABTs) are usually not associated with a phenotype; however, rarely, ABTs segregate with discordant phenotypes in family members carrying identical rearrangements. The current study was a follow-up investigation of four familial ABTs, where whole exome sequencing (WES) was implemented as a diagnostic tool to identify the underlying genetic aetiology of the patients' phenotypes. Data were analysed using an in-house bioinformatics pipeline alongside VarSome Clinical. WES findings were validated with Sanger sequencing, while the impact of splicing and missense variants was assessed by reverse-transcription PCR and in silico tools, respectively. Novel candidate variants were identified in three families. In family 1, it was shown that the de novo pathogenic STXBP1 variant (NM_003165.6:c.1110+2T>G) affected splicing and segregated with the patient's phenotype. In family 2, a likely pathogenic TUBA1A variant (NM_006009.4:c.875C>T, NP_006000.2:p.(Thr292Ile)) could explain the patient's symptoms. In family 3, an SCN1A variant of uncertain significance (NM_006920.6:c.5060A>G, NP_008851.3:p.(Glu1687Gly)) required additional evidence to sufficiently support causality. This first report of WES application in familial ABT carriers with discordant phenotypes supported our previous findings describing such rearrangements as coincidental. Thus, WES can be recommended as a complementary test to find the monogenic cause of aberrant phenotypes in familial ABT carriers.
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Lu G, Zhang Y, Xia H, He X, Xu P, Wu L, Li D, Ma L, Wu J, Peng Q. Identification of a de novo mutation of the FOXG1 gene and comprehensive analysis for molecular factors in Chinese FOXG1-related encephalopathies. Front Mol Neurosci 2022; 15:1039990. [PMID: 36568277 PMCID: PMC9768341 DOI: 10.3389/fnmol.2022.1039990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/11/2022] [Indexed: 12/12/2022] Open
Abstract
Background FOXG1-related encephalopathy, also known as FOXG1 syndrome or FOXG1-related disorder, affects most aspects of development and causes microcephaly and brain malformations. This syndrome was previously considered to be the congenital variant of Rett syndrome. The abnormal function or expression of FOXG1, caused by intragenic mutations, microdeletions or microduplications, was considered to be crucial pathological factor for this disorder. Currently, most of the FOXG1-related encephalopathies have been identified in Europeans and North Americans, and relatively few Chinese cases were reported. Methods Array-Comparative Genomic Hybridization (Array-CGH) and whole-exome sequencing (WES) were carried out for the proband and her parent to detect pathogenic variants. Results A de novo nonsense mutation (c.385G>T, p.Glu129Ter) of FOXG1 was identified in a female child in a cohort of 73 Chinese children with neurodevelopmental disorders/intellectual disorders (NDDs/IDs). In order to have a comprehensive view of FOXG1-related encephalopathy in China, relevant published reports were browsed and twelve cases with mutations in FOXG1 or copy number variants (CNVs) involving FOXG1 gene were involved in the analysis eventually. Feeding difficulties, seizures, delayed speech, corpus callosum hypoplasia and underdevelopment of frontal and temporal lobes occurred in almost all cases. Out of the 12 cases, eight patients (66.67%) had single-nucleotide mutations of FOXG1 gene and four patients (33.33%) had CNVs involving FOXG1 (3 microdeletions and 1 microduplication). The expression of FOXG1 could also be potentially disturbed by deletions of several brain-active regulatory elements located in intergenic FOXG1-PRKD1 region. Further analysis indicated that PRKD1 might be a cooperating factor to regulate the expression of FOXG1, MECP2 and CDKL5 to contribute the RTT/RTT-like disorders. Discussion This re-analysis would broaden the existed knowledge about the molecular etiology and be helpful for diagnosis, treatment, and gene therapy of FOXG1-related disorders in the future.
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Affiliation(s)
- Guanting Lu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People's Hospital, Deyang, China
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Yan Zhang
- Department of Obstetrics and Gynecology, Strategic Support Force Medical Center, Beijing, China
| | - Huiyun Xia
- Department of Child Healthcare, Shenzhen Baoan Women's and Children's Hospital, Jinan University, Shenzhen, China
| | - Xiaoyan He
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People's Hospital, Deyang, China
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Pei Xu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People's Hospital, Deyang, China
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Lianying Wu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People's Hospital, Deyang, China
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Ding Li
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Liya Ma
- Department of Child Healthcare, Shenzhen Baoan Women's and Children's Hospital, Jinan University, Shenzhen, China
| | - Jin Wu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People's Hospital, Deyang, China
- Key Laboratory of Tumor Molecular Research of Deyang, Deyang, China
| | - Qiongling Peng
- Department of Child Healthcare, Shenzhen Baoan Women's and Children's Hospital, Jinan University, Shenzhen, China
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8
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Cali E, Rocca C, Salpietro V, Houlden H. Epileptic Phenotypes Associated With SNAREs and Related Synaptic Vesicle Exocytosis Machinery. Front Neurol 2022; 12:806506. [PMID: 35095745 PMCID: PMC8792400 DOI: 10.3389/fneur.2021.806506] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/16/2021] [Indexed: 01/29/2023] Open
Abstract
SNAREs (soluble N-ethylmaleimide sensitive factor attachment protein receptor) are an heterogeneous family of proteins that, together with their key regulators, are implicated in synaptic vesicle exocytosis and synaptic transmission. SNAREs represent the core component of this protein complex. Although the specific mechanisms of the SNARE machinery is still not completely uncovered, studies in recent years have provided a clearer understanding of the interactions regulating the essential fusion machinery for neurotransmitter release. Mutations in genes encoding SNARE proteins or SNARE complex associated proteins have been associated with a variable spectrum of neurological conditions that have been recently defined as “SNAREopathies.” These include neurodevelopmental disorder, autism spectrum disorder (ASD), movement disorders, seizures and epileptiform abnormalities. The SNARE phenotypic spectrum associated with seizures ranges from simple febrile seizures and infantile spasms, to severe early-onset epileptic encephalopathies. Our study aims to review and delineate the epileptic phenotypes associated with dysregulation of synaptic vesicle exocytosis and transmission, focusing on the main proteins of the SNARE core complex (STX1B, VAMP2, SNAP25), tethering complex (STXBP1), and related downstream regulators.
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Affiliation(s)
- Elisa Cali
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Clarissa Rocca
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Vincenzo Salpietro
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
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9
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Barki M, Xue H. GABRB2, a key player in neuropsychiatric disorders and beyond. Gene 2022; 809:146021. [PMID: 34673206 DOI: 10.1016/j.gene.2021.146021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 08/05/2021] [Accepted: 09/14/2021] [Indexed: 01/11/2023]
Abstract
The GABA receptors represent the main inhibitory system in the central nervous system that ensure synaptogenesis, neurogenesis, and the regulation of neuronal plasticity and learning. GABAA receptors are pentameric in structure and belong to the Cys-loop superfamily. The GABRB2 gene, located on chromosome 5q34, encodes the β2 subunit that combines with the α and γ subunits to form the major subtype of GABAA receptors, which account for 43% of all GABAA receptors in the mammalian brain. Each subunit probably consists of an extracellular N-terminal domain, four membrane-spanning segments, a large intracellular loop between TM3 and TM4, and an extracellular C-terminal domain. Alternative splicing of the RNA transcript of the GABRB2 gene gives rise at least to four long and short isoforms with dissimilar electrophysiological properties. Furthermore, GABRB2 is imprinted and subjected to epigenetic regulation and positive selection. It has been associated with schizophrenia first in Han Chinese, and subsequently validated in other populations. Gabrb2 knockout mice also exhibited schizophrenia-like behavior and neuroinflammation that were ameliorated by the antipsychotic drug risperidone. GABRB2 was also associated with other neuropsychiatric disorders including bipolar disorder, epilepsy, autism spectrum disorder, Alzheimer's disease, frontotemporal dementia, substance dependence, depression, internet gaming disorder, and premenstrual dysphoric disorder. Recently, it has been postulated that GABRB2 might be a potential marker for different cancer types. As GABRB2 has a pivotal role in the central nervous system and is increasingly recognized to contribute to human diseases, further understanding of its structure and function may expedite the generation of new therapeutic approaches.
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Affiliation(s)
- Manel Barki
- Center for Cancer Genomics, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Hong Xue
- Center for Cancer Genomics, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China; Division of Life Science and Applied Genomics Center, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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10
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Yang P, Broadbent R, Prasad C, Levin S, Goobie S, Knoll JH, Prasad AN. De novo STXBP1 Mutations in Two Patients With Developmental Delay With or Without Epileptic Seizures. Front Neurol 2022; 12:804078. [PMID: 35002943 PMCID: PMC8739808 DOI: 10.3389/fneur.2021.804078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022] Open
Abstract
Objectives: Mutations in the STXBP1 gene have been associated with epileptic encephalopathy. Previous studies from in vitro neuroblastoma 2A cells showed that haploinsufficiency of STXBP1 is the mechanism for epileptic encephalopathy. In this ex vivo study, STXPB1 DNA mutations and RNA expression were assessed from two patients to help understand the impact of STXBP1 mutations on the disease etiology and mechanism. Methods: Microarray analysis and DNA sequencing were performed on two children with development delay, one with and one without infantile spasms. Different pathogenic mutations of STXBP1 were identified in the patients and RNA expression of STXPB1 was then performed by RT-Q-PCR on RNA extracted from blood samples of each patient. Results: Pathogenic deletion [of exons 13–20 and 3′ downstream of STXBP1] and nonsense mutation [c.1663G>T (p.Glu555X) in exon 18 of STXBP1] were detected from the two patients, respectively. RNA analysis showed that 1) the deletion mediated RNA decay, and that 2) no RNA decay was identified for the nonsense mutation at codon 555 which predicts a truncated STXBP1 protein. Significance: Our RNA expression analyses from the patient blood samples are the first ex vivo studies to support that both haploinsufficiency and truncation of STXBP1 protein (either dominant negative or haploinsufficiency) are causative mechanisms for epileptic encephalopathies, intellectual disability and developmental delay. The RNA assay also suggests that escape from nonsense-mediated RNA decay is possible when the nonsense mutation resides <50 nucleotides upstream of the last coding exon-exon junction even in the presence of additional non-coding exons that are 3′ downstream of the last coding exon.
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Affiliation(s)
- Ping Yang
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.,London Health Sciences Centre, London, ON, Canada
| | - Robert Broadbent
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.,London Health Sciences Centre, London, ON, Canada
| | - Chitra Prasad
- Department of Paediatrics, London Health Sciences Centre, Western University, London, ON, Canada
| | - Simon Levin
- Department of Paediatrics, London Health Sciences Centre, Western University, London, ON, Canada
| | - Sharan Goobie
- Maritime Medical Genetic Service, Department of Paediatrics, Izaak Walton Killam Health Centre, Halifax, NS, Canada
| | - Joan H Knoll
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.,London Health Sciences Centre, London, ON, Canada
| | - Asuri N Prasad
- Department of Paediatrics, London Health Sciences Centre, Western University, London, ON, Canada
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11
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Yang Y, Niu X, Cheng M, Zeng Q, Deng J, Tian X, Wang Y, Yu J, Shi W, Wu W, Ma J, Li Y, Yang X, Zhang X, Jia T, Yang Z, Liao J, Sun Y, Zheng H, Sun S, Sun D, Jiang Y, Zhang Y. Phenotypic Spectrum and Prognosis of Epilepsy Patients With GABRG2 Variants. Front Mol Neurosci 2022; 15:809163. [PMID: 35359574 PMCID: PMC8964129 DOI: 10.3389/fnmol.2022.809163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/28/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE This study aimed to obtain a comprehensive understanding of the genetic and phenotypic aspects of GABRG2-related epilepsy and its prognosis and to explore the potential prospects for personalized medicine. METHODS Through a multicenter collaboration in China, we analyzed the genotype-phenotype correlation and antiseizure medication (ASM) of patients with GABRG2-related epilepsy. The three-dimensional protein structure of the GABRG2 variant was modeled to predict the effect of GABRG2 missense variants using PyMOL 2.3 software. RESULTS In 35 patients with GABRG2 variants, 22 variants were de novo, and 18 variants were novel. The seizure onset age was ranged from 2 days after birth to 34 months (median age: 9 months). The seizure onset age was less than 1 year old in 22 patients (22/35, 62.9%). Seizure types included focal seizures (68.6%), generalized tonic-clonic seizures (60%), myoclonic seizures (14.3%), and absence seizures (11.4%). Other clinical features included fever-sensitive seizures (91.4%), cluster seizures (57.1%), and developmental delay (45.7%). Neuroimaging was abnormal in 2 patients, including dysplasia of the frontotemporal cortex and delayed myelination of white matter. Twelve patients were diagnosed with febrile seizures plus, eleven with epilepsy and developmental delay, two with Dravet syndrome, two with developmental and epileptic encephalopathy, two with focal epilepsy, two with febrile seizures, and four with unclassified epilepsy. The proportions of patients with missense variants in the extracellular region and the transmembrane region exhibiting developmental delay were 40% and 63.2%, respectively. The last follow-up age ranged from 11 months to 17 years. Seizures were controlled in 71.4% of patients, and 92% of their seizures were controlled by valproate and/or levetiracetam. CONCLUSION The clinical features of GABRG2-related epilepsy included seizure onset, usually in infancy, and seizures were fever-sensitive. More than half of the patients had cluster seizures. Phenotypes of GABRG2-related epilepsy were ranged from mild febrile seizures to severe epileptic encephalopathies. Most patients with GABRG2 variants who experienced seizures had a good prognosis. Valproate and levetiracetam were effective treatments for most patients.
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Affiliation(s)
- Ying Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xueyang Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Miaomiao Cheng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Qi Zeng
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jie Deng
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, Beijing, China
| | - Xiaojuan Tian
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, Beijing, China
| | - Yi Wang
- Department of Neurology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Jing Yu
- Department of Neurology, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Ürümqi, China
| | - Wenli Shi
- Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Wenjuan Wu
- Department of Neurology, Hebei Children’s Hospital, Shijiazhuang, China
| | - Jiehui Ma
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yufen Li
- Department of Pediatrics, Linyi People’s Hospital, Linyi, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoli Zhang
- Department of Pediatrics, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Tianming Jia
- Department of Pediatrics, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yan Sun
- Department of Neurology, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Ürümqi, China
| | - Hong Zheng
- Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Suzhen Sun
- Department of Neurology, Hebei Children’s Hospital, Shijiazhuang, China
| | - Dan Sun
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- *Correspondence: Yuehua Zhang,
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12
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SCN2A Pathogenic Variants and Epilepsy: Heterogeneous Clinical, Genetic and Diagnostic Features. Brain Sci 2021; 12:brainsci12010018. [PMID: 35053762 PMCID: PMC8773615 DOI: 10.3390/brainsci12010018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/19/2022] Open
Abstract
Pathogenic variants of the SCN2A gene (MIM 182390) are associated with several epileptic syndromes ranging from benign familial neonatal-infantile seizures (BFNIS) to early infantile epileptic encephalopathy. The aim of this work was to describe clinical features among five patients with concomitant SCN2A gene variants and cryptogenic epileptic syndromes, thus expanding the SCN2A spectrum of phenotypic heterogeneity. De novo variants were identified in four patients, while one inherited variant was identified in a patient with an unaffected carrier biological father with somatic mosaicism. Two of five patients were diagnosed with a neonatal epileptic encephalopathy. The remaining three patients manifested a focal epileptic syndrome associated with autistic spectrum disorders (ASD) or with a variable degree of intellectual disability (ID), one of them displaying a hitherto unreported atypical late onset epilepsy. Overall, the pattern of clinical manifestations among these patients suggest that any observed neurological impairment may not be directly related to the severity of the electroclinical pattern, but instead likely associated with the mutation itself. Moreover, our results highlight the importance of SCN2A mutational screening in cases of ID/ASD with or without epilepsy.
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13
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Efficacy of levetiracetam in STXBP1 encephalopathy with different phenotypic and genetic spectra. Seizure 2021; 95:64-74. [PMID: 35007884 DOI: 10.1016/j.seizure.2021.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 12/08/2021] [Accepted: 12/15/2021] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Syntaxin binding protein 1 (STXBP1) plays an important role in the release of synaptic vesicles. STXBP1-related encephalopathy is a brain dysfunction caused by STXBP1 variation. Levetiracetam (LEV) exerts antiepileptic effects by binding to synaptic vesicle protein 2A (SV2A). This study aimed to analyze the prognosis of LEV treatment of STXBP1 encephalopathy (STXBP1-E) and the correlation among genotype, phenotype, and LEV efficacy. METHODS Patients with pathogenic STXBP1 variants were collected from multiple centers, and their clinical history, video electroencephalogram (vEEG) characteristics, imaging examination data, and anti-seizure medication (ASM) history were systematically analyzed. The ASMs related to the prognosis were explored. RESULTS Forty patients with STXBP1-E were enrolled in this study. The detailed ASM usage of 37 patients was recorded without intervening in ASM selection. At the endpoint of six months treatment, the results of Fisher's exact test showed that in all ASMs, LEV affected the prognosis of patients with STXBP1-E. LEV was effective in improving the partial remission rate but did not achieve seizure freedom. However, LEV monotherapy could achieve seizure freedom in patients with other early-onset epileptic and encephalopathy. For refractory West syndrome (WS) or Ohtahara syndrome (OS), LEV combined with other ASMs could improve the seizure remission rate. CONCLUSION LEV increased the seizure reduction rate and improved the vEEG characteristics in patients with STXBP1-E, but not seizure freedom. LEV combined with other ASMs could increase the seizure reduction rate, especially for refractory WS or OS. Thus, LEV could be considered after identifying the pathogenicity of STXBP1 variants.
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14
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Spagnoli C, Fusco C, Pisani F. Rett Syndrome Spectrum in Monogenic Developmental-Epileptic Encephalopathies and Epilepsies: A Review. Genes (Basel) 2021; 12:genes12081157. [PMID: 34440332 PMCID: PMC8394997 DOI: 10.3390/genes12081157] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 01/22/2023] Open
Abstract
INTRODUCTION Progress in the clinical application of next-generation-sequencing-based techniques has resulted in a dramatic increase in the recognized genetic heterogeneity of the Rett syndrome spectrum (RSS). Our awareness of the considerable overlap with pediatric-onset epilepsies and epileptic/developmental encephalopathies (EE/DE) genes is also growing, and the presence of variable clinical features inside a general frame of commonalities has drawn renewed attention into deep phenotyping. METHODS We decided to review the medical literature on atypical Rett syndrome and "Rett-like" phenotypes, with special emphasis on described cases with pediatric-onset epilepsies and/or EE-DE, evaluating Neul's criteria for Rett syndrome and associated movement disorders and notable stereotypies. RESULTS "Rett-like" features were described in syndromic and non-syndromic monogenic epilepsy- and DE/EE-related genes, in "intellectual disability plus epilepsy"-related genes and in neurodegenerative disorders. Additionally, prominent stereotypies can be observed in monogenic complex neurodevelopmental disorders featuring epilepsy with or without autistic features outside of the RSS. CONCLUSIONS Patients share a complex neurodevelopmental and neurological phenotype (developmental delay, movement disorder) with impaired gait, abnormal tone and hand stereotypies. However, the presence and characteristics of regression and loss of language and functional hand use can differ. Finally, the frequency of additional supportive criteria and their distribution also vary widely.
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Affiliation(s)
- Carlotta Spagnoli
- Child Neurology Unit, AUSL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
- Correspondence:
| | - Carlo Fusco
- Child Neurology Unit, AUSL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Francesco Pisani
- Child Neuropsychiatry Unit, University-Hospital of Parma, 43123 Parma, Italy;
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15
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Lee J, Avramets D, Jeon B, Choo H. Modulation of Serotonin Receptors in Neurodevelopmental Disorders: Focus on 5-HT7 Receptor. Molecules 2021; 26:molecules26113348. [PMID: 34199418 PMCID: PMC8199608 DOI: 10.3390/molecules26113348] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 12/17/2022] Open
Abstract
Since neurodevelopmental disorders (NDDs) influence more than 3% of children worldwide, there has been intense investigation to understand the etiology of disorders and develop treatments. Although there are drugs such as aripiprazole, risperidone, and lurasidone, these medications are not cures for the disorders and can only help people feel better or alleviate their symptoms. Thus, it is required to discover therapeutic targets in order to find the ultimate treatments of neurodevelopmental disorders. It is suggested that abnormal neuronal morphology in the neurodevelopment process is a main cause of NDDs, in which the serotonergic system is emerging as playing a crucial role. From this point of view, we noticed the correlation between serotonin receptor subtype 7 (5-HT7R) and NDDs including autism spectrum disorder (ASD), fragile X syndrome (FXS), and Rett syndrome (RTT). 5-HT7R modulators improved altered behaviors in animal models and also affected neuronal morphology via the 5-HT7R/G12 signaling pathway. Through the investigation of recent studies, it is suggested that 5-HT7R could be a potential therapeutic target for the treatment of NDDs.
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Affiliation(s)
- Jieon Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Korea; (J.L.); (D.A.)
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - Diana Avramets
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Korea; (J.L.); (D.A.)
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - Byungsun Jeon
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Korea; (J.L.); (D.A.)
- Correspondence: (B.J.); (H.C.); Tel.: +82-2-958-5191 (B.J.); +82-2-958-5157 (H.C.)
| | - Hyunah Choo
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Korea; (J.L.); (D.A.)
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
- Correspondence: (B.J.); (H.C.); Tel.: +82-2-958-5191 (B.J.); +82-2-958-5157 (H.C.)
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16
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Fontana A, Consentino MC, Motta M, Costanza G, Lo Bianco M, Marino S, Falsaperla R, Praticò AD. Syntaxin Binding Protein 1 Related Epilepsies. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractSyntaxin binding protein 1 (STXBP1), commonly known as MUNC18–1, is a member of SEC1 family membrane trafficking proteins; their function consists in controlling the soluble N-ethylmaleimide-sensitive factor attachment protein receptors complex assembly, making them essentials regulators of vesicle fusion. The precise function and molecular mechanism through which Munc18–1 contributes to neurotransmitter releasing is not entirely understood, but several evidences suggest its probable role in exocytosis. In 2008, heterozygous de novo mutations in neuronal protein Munc18–1 were first referred as a cause of Ohtahara syndrome development. Currently, a wide examination of the published data proved that 3.1% of patients with severe epilepsy carry a pathogenic de novo mutation including STXBP1 and approximately 10.2% of early onset epileptic encephalopathy is due to an aberrant STXBP1 form codified by the mutated gene. STXBP1 mutations can be associated to a wide clinical heterogeneity. All affected individuals show developmental delay and approximately the 95% of cases have seizures and early onset epileptic encephalopathy, characterized by infantile spasms as the main consistent feature. Burst suppression pattern and hypsarrhythmia are the most frequent EEG anomalies. Other neuronal disorders include Rett syndrome and behavioral and movement disorders. Mild dysmorphic features have been detected in a small number of cases. No genotype–phenotype correlation has been reported. Management of STXBP1 encephalopathy requires a multidisciplinary approach, including epilepsy control and neurological rehabilitation. About 25% of patients are refractory to standard therapy. A single or combined antiepileptic drugs may be required. Several studies described vigabatrin, valproic acid, levetiracetam, topiramate, clobazam, and oxcarbazepine as effective in seizure control. Lamotrigine, zonisamide, and phenobarbital are also commonly used. To date, it remains unclear which therapy is the most effective. Severe morbidity and high mortality are inevitable consequences in some of these patients.
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Affiliation(s)
- Alessandra Fontana
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Maria Chiara Consentino
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Milena Motta
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Giuseppe Costanza
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Simona Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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17
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Abramov D, Guiberson NGL, Burré J. STXBP1 encephalopathies: Clinical spectrum, disease mechanisms, and therapeutic strategies. J Neurochem 2021; 157:165-178. [PMID: 32643187 PMCID: PMC7812771 DOI: 10.1111/jnc.15120] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/24/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022]
Abstract
Mutations in Munc18-1/STXBP1 (syntaxin-binding protein 1) are linked to various severe early epileptic encephalopathies and neurodevelopmental disorders. Heterozygous mutations in the STXBP1 gene include missense, nonsense, frameshift, and splice site mutations, as well as intragenic deletions and duplications and whole-gene deletions. No genotype-phenotype correlation has been identified so far, and patients are treated by anti-epileptic drugs because of the lack of a specific disease-modifying therapy. The molecular disease mechanisms underlying STXBP1-linked disorders are yet to be fully understood, but both haploinsufficiency and dominant-negative mechanisms have been proposed. This review focuses on the current understanding of the phenotypic spectrum of STXBP1-linked disorders, as well as discusses disease mechanisms in the context of the numerous pathways in which STXBP1 functions in the brain. We additionally evaluate the available animal models to study these disorders and highlight potential therapeutic approaches for treating these devastating diseases.
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Affiliation(s)
- Debra Abramov
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Noah Guy Lewis Guiberson
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Jacqueline Burré
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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18
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Deshmukh AL, Porro A, Mohiuddin M, Lanni S, Panigrahi GB, Caron MC, Masson JY, Sartori AA, Pearson CE. FAN1, a DNA Repair Nuclease, as a Modifier of Repeat Expansion Disorders. J Huntingtons Dis 2021; 10:95-122. [PMID: 33579867 PMCID: PMC7990447 DOI: 10.3233/jhd-200448] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
FAN1 encodes a DNA repair nuclease. Genetic deficiencies, copy number variants, and single nucleotide variants of FAN1 have been linked to karyomegalic interstitial nephritis, 15q13.3 microdeletion/microduplication syndrome (autism, schizophrenia, and epilepsy), cancer, and most recently repeat expansion diseases. For seven CAG repeat expansion diseases (Huntington's disease (HD) and certain spinocerebellar ataxias), modification of age of onset is linked to variants of specific DNA repair proteins. FAN1 variants are the strongest modifiers. Non-coding disease-delaying FAN1 variants and coding disease-hastening variants (p.R507H and p.R377W) are known, where the former may lead to increased FAN1 levels and the latter have unknown effects upon FAN1 functions. Current thoughts are that ongoing repeat expansions in disease-vulnerable tissues, as individuals age, promote disease onset. Fan1 is required to suppress against high levels of ongoing somatic CAG and CGG repeat expansions in tissues of HD and FMR1 transgenic mice respectively, in addition to participating in DNA interstrand crosslink repair. FAN1 is also a modifier of autism, schizophrenia, and epilepsy. Coupled with the association of these diseases with repeat expansions, this suggests a common mechanism, by which FAN1 modifies repeat diseases. Yet how any of the FAN1 variants modify disease is unknown. Here, we review FAN1 variants, associated clinical effects, protein structure, and the enzyme's attributed functional roles. We highlight how variants may alter its activities in DNA damage response and/or repeat instability. A thorough awareness of the FAN1 gene and FAN1 protein functions will reveal if and how it may be targeted for clinical benefit.
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Affiliation(s)
- Amit L Deshmukh
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Antonio Porro
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Mohiuddin Mohiuddin
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Stella Lanni
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Gagan B Panigrahi
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Marie-Christine Caron
- Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, Quebec, Canada.,Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Québec City, Quebec, Canada
| | - Jean-Yves Masson
- Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, Quebec, Canada.,Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Québec City, Quebec, Canada
| | - Alessandro A Sartori
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Christopher E Pearson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada.,University of Toronto, Program of Molecular Genetics, Toronto, Ontario, Canada
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19
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Trollmann R. Neuromonitoring in Neonatal-Onset Epileptic Encephalopathies. Front Neurol 2021; 12:623625. [PMID: 33603712 PMCID: PMC7884638 DOI: 10.3389/fneur.2021.623625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/12/2021] [Indexed: 12/31/2022] Open
Abstract
Considering the wide spectrum of etiologies of neonatal-onset epileptic encephalopathies (EE) and their unfavorable consequences for neurodevelopmental prognoses, neuromonitoring at-risk neonates is increasingly important. EEG is highly sensitive for early identification of electrographic seizures and abnormal background activity. Amplitude-integrated EEG (aEEG) is recommended as a useful bedside monitoring method but as a complementary tool because of methodical limitations. It is of special significance in monitoring neonates with acute symptomatic as well as structural, metabolic and genetic neonatal-onset EE, being at high risk of electrographic-only and prolonged seizures. EEG/aEEG monitoring is established as an adjunctive tool to confirm perinatal hypoxic-ischemic encephalopathy (HIE). In neonates with HIE undergoing therapeutic hypothermia, burst suppression pattern is associated with good outcomes in about 40% of the patients. The prognostic specificity of EEG/aEEG is lower compared to cMRI. As infants with HIE may develop seizures after cessation of hypothermia, recording for at least 24 h after the last seizure is recommended. Progress in the identification of genetic etiology of neonatal EE constantly increases. However, presently, no specific EEG changes indicative of a genetic variant have been characterized, except for individual variants associated with typical EEG patterns (e.g., KCNQ2, KCNT1). Long-term monitoring studies are necessary to define and classify electro-clinical patterns of neonatal-onset EE.
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Affiliation(s)
- Regina Trollmann
- Department of Pediatrics and Pediatric Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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20
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El Achkar CM, Harrer M, Smith L, Kelly M, Iqbal S, Maljevic S, Niturad CE, Vissers LELM, Poduri A, Yang E, Lal D, Lerche H, Møller RS, Olson HE. Characterization of the GABRB2-Associated Neurodevelopmental Disorders. Ann Neurol 2020; 89:573-586. [PMID: 33325057 DOI: 10.1002/ana.25985] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We aimed to characterize the phenotypic spectrum and functional consequences associated with variants in the gene GABRB2, coding for the γ-aminobutyric acid type A (GABAA ) receptor subunit β2. METHODS We recruited and systematically evaluated 25 individuals with variants in GABRB2, 17 of whom are newly described and 8 previously reported with additional clinical data. Functional analysis was performed using a Xenopus laevis oocyte model system. RESULTS Our cohort of 25 individuals from 22 families with variants in GABRB2 demonstrated a range of epilepsy phenotypes from genetic generalized epilepsy to developmental and epileptic encephalopathy. Fifty-eight percent of individuals had pharmacoresistant epilepsy; response to medications targeting the GABAergic pathway was inconsistent. Developmental disability (present in 84%) ranged from mild intellectual disability to severe global disability; movement disorders (present in 44%) included choreoathetosis, dystonia, and ataxia. Disease-associated variants cluster in the extracellular N-terminus and transmembrane domains 1-3, with more severe phenotypes seen in association with variants in transmembrane domains 1 and 2 and the allosteric binding site between transmembrane domains 2 and 3. Functional analysis of 4 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents. INTERPRETATION GABRB2-related epilepsy ranges broadly in severity from genetic generalized epilepsy to developmental and epileptic encephalopathies. Developmental disability and movement disorder are key features. The phenotypic spectrum is comparable to other GABAA receptor-encoding genes. Phenotypic severity varies by protein domain. Experimental evidence supports loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders. ANN NEUROL 2021;89:573-586.
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Affiliation(s)
- Christelle M El Achkar
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Merle Harrer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lacey Smith
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA
| | - McKenna Kelly
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Dartmouth Geisel School of Medicine, Hanover, NH
| | - Sumaiya Iqbal
- Center for Development of Therapeutics and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Snezana Maljevic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Cristina E Niturad
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lisenka E L M Vissers
- Department of Human Genetics, Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Boston, MA
| | - Dennis Lal
- Cleveland Clinic Genomic Medicine Institute and Neurological Institute, Cleveland, OH
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Heather E Olson
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
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21
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Sandweiss AJ, Brandt VL, Zoghbi HY. Advances in understanding of Rett syndrome and MECP2 duplication syndrome: prospects for future therapies. Lancet Neurol 2020; 19:689-698. [PMID: 32702338 DOI: 10.1016/s1474-4422(20)30217-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 01/07/2023]
Abstract
The X-linked gene encoding MECP2 is involved in two severe and complex neurodevelopmental disorders. Loss of function of the MeCP2 protein underlies Rett syndrome, whereas duplications of the MECP2 locus cause MECP2 duplication syndrome. Research on the mechanisms by which MeCP2 exerts effects on gene expression in neurons, studies of animal models bearing different disease-causing mutations, and more in-depth observations of clinical presentations have clarified some issues even as they have raised further questions. Yet there is enough evidence so far to suggest possible approaches to therapy for these two diseases that could go beyond attempting to address specific signs and symptoms (of which there are many) and instead target the pathophysiology underlying MECP2 disorders. Further work could bring antisense oligonucleotides, deep brain stimulation, and gene therapy into the clinic within the next decade or so.
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Affiliation(s)
- Alexander J Sandweiss
- Department of Pediatrics, Section of Neurology and Developmental Neurosciences, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Vicky L Brandt
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Huda Y Zoghbi
- Department of Pediatrics, Section of Neurology and Developmental Neurosciences, Baylor College of Medicine, Houston, TX, USA; Howard Hughes Medical Institute, and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA.
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22
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Kaur S, Van Bergen NJ, Verhey KJ, Nowell CJ, Budaitis B, Yue Y, Ellaway C, Brunetti-Pierri N, Cappuccio G, Bruno I, Boyle L, Nigro V, Torella A, Roscioli T, Cowley MJ, Massey S, Sonawane R, Burton MD, Schonewolf-Greulich B, Tümer Z, Chung WK, Gold WA, Christodoulou J. Expansion of the phenotypic spectrum of de novo missense variants in kinesin family member 1A (KIF1A). Hum Mutat 2020; 41:1761-1774. [PMID: 32652677 DOI: 10.1002/humu.24079] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022]
Abstract
Defects in the motor domain of kinesin family member 1A (KIF1A), a neuron-specific ATP-dependent anterograde axonal transporter of synaptic cargo, are well-recognized to cause a spectrum of neurological conditions, commonly known as KIF1A-associated neurological disorders (KAND). Here, we report one mutation-negative female with classic Rett syndrome (RTT) harboring a de novo heterozygous novel variant [NP_001230937.1:p.(Asp248Glu)] in the highly conserved motor domain of KIF1A. In addition, three individuals with severe neurodevelopmental disorder along with clinical features overlapping with KAND are also reported carrying de novo heterozygous novel [NP_001230937.1:p.(Cys92Arg) and p.(Pro305Leu)] or previously reported [NP_001230937.1:p.(Thr99Met)] variants in KIF1A. In silico tools predicted these variants to be likely pathogenic, and 3D molecular modeling predicted defective ATP hydrolysis and/or microtubule binding. Using the neurite tip accumulation assay, we demonstrated that all novel KIF1A variants significantly reduced the ability of the motor domain of KIF1A to accumulate along the neurite lengths of differentiated SH-SY5Y cells. In vitro microtubule gliding assays showed significantly reduced velocities for the variant p.(Asp248Glu) and reduced microtubule binding for the p.(Cys92Arg) and p.(Pro305Leu) variants, suggesting a decreased ability of KIF1A to move along microtubules. Thus, this study further expanded the phenotypic characteristics of KAND individuals with pathogenic variants in the KIF1A motor domain to include clinical features commonly seen in RTT individuals.
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Affiliation(s)
- Simranpreet Kaur
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Nicole J Van Bergen
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Cameron J Nowell
- Drug Discover Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia
| | - Breane Budaitis
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan
| | - Yang Yue
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Carolyn Ellaway
- Discipline of Genomic Medicine, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Western Sydney Genetics Program, Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, University of Naples "Federico II", Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Gerarda Cappuccio
- Department of Translational Medicine, University of Naples "Federico II", Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Irene Bruno
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Lia Boyle
- Division of Molecular Genetics, Columbia University Irving Medical Center, New York, New York
| | - Vincenzo Nigro
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Annalaura Torella
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Tony Roscioli
- New South Wales Health Pathology, Randwick, New South Wales, Australia.,Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
| | - Mark J Cowley
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia.,Children's Cancer Institute, Lowy Cancer Research Centre, UNSW, Sydney, New South Wales, Australia
| | - Sean Massey
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Rhea Sonawane
- Faculty of Science, Engineering and Built Environment, Deakin University, Melbourne, Australia
| | - Matthew D Burton
- Flow Cytometry and Imaging Facility, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Bitten Schonewolf-Greulich
- Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Zeynep Tümer
- Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Wendy K Chung
- Departments of Paediatrics and Medicine, Columbia University Medical Center, New York, New York
| | - Wendy A Gold
- Molecular Neurobiology Research Laboratory, Kids Research, Children's Hospital at Westmead, and The Children's Medical Research Institute, Westmead, New South Wales, Australia.,Kids Neuroscience Centre, Kids Research, Children's Hospital at Westmead, Westmead, New South Wales, Australia.,School of Medical Sciences and Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Discipline of Genomic Medicine, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Victoria, Australia
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23
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Peron A, Iascone M, Salvatici E, Cavirani B, Marchetti D, Corno S, Vignoli A. PIGW-related glycosylphosphatidylinositol deficiency: Description of a new patient and review of the literature. Am J Med Genet A 2020; 182:1477-1482. [PMID: 32198969 DOI: 10.1002/ajmg.a.61555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/20/2020] [Accepted: 03/02/2020] [Indexed: 12/13/2022]
Abstract
Inherited glycosylphosphatidylinositol (GPI) deficiencies are a group of clinically and genetically heterogeneous conditions belonging to the congenital disorders of glycosylation. PIGW is involved in GPI biosynthesis and modification, and biallelic pathogenic variants in this gene cause autosomal recessive GPI biosynthesis defect 11. Only five patients and two fetuses have been reported in the literature thus far. Here we describe a new patient with a novel homozygous missense variant in PIGW, who presented with hypotonia, severe intellectual disability, early-onset epileptic seizures, brain abnormalities, nystagmus, hand stereotypies, recurrent respiratory infections, distinctive facial features, and hyperphosphatasia. Our report expands the phenotype of GPI biosynthesis defect 11 to include stereotypies and recurrent respiratory infections. A detailed and long-term analysis of the electroclinical characteristics and review of the literature suggest that early-onset epileptic seizures are a key manifestation of GPI biosynthesis defect 11. West syndrome and focal-onset epileptic seizures are the most common seizure types, and the fronto-temporal regions may be the most frequently involved areas in these patients.
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Affiliation(s)
- Angela Peron
- Child Neuropsychiatry Unit-Epilepsy Center (Medical Genetics Clinic), ASST Santi Paolo e Carlo, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.,Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Maria Iascone
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Elisabetta Salvatici
- Department of Pediatrics, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy
| | - Benedetta Cavirani
- Child Neuropsychiatry Unit-Epilepsy Center, ASST Santi Paolo e Carlo, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Daniela Marchetti
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Silvia Corno
- Child Neuropsychiatry Unit-Epilepsy Center, ASST Santi Paolo e Carlo, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Aglaia Vignoli
- Child Neuropsychiatry Unit-Epilepsy Center, ASST Santi Paolo e Carlo, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
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24
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Peron A, Novara F, La Briola F, Merati E, Giannusa E, Segalini E, Anniballi G, Vignoli A, Ciccone R, Canevini MP. Missense variants in the Arg206 residue of HNRNPH2: Further evidence of causality and expansion of the phenotype. Am J Med Genet A 2020; 182:823-828. [PMID: 31943778 DOI: 10.1002/ajmg.a.61486] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 12/05/2019] [Accepted: 12/27/2019] [Indexed: 11/11/2022]
Abstract
Missense variants in HNRNPH2 cause Bain type syndromic X-linked intellectual disability (XLID). To date, only six affected females and three affected males have been reported in the literature, and the phenotype has yet to be delineated in detail. Here, we report on a 35-year-old female with a novel de novo variant in HNRNPH2, providing further evidence that missense changes in the nuclear localization sequence cause Bain type XLID and that aminoacid 206 likely represents a mutational hotspot. We expand the phenotype of Bain type XLID to include breathing, sleep and movement disorders, cerebellar vermis hypoplasia, stereotypies, and hypersensitivity to noise. Our data indicate that the phenotype may be broader and more variable than initially reported, and suggest Rett syndrome as a possible differential diagnosis.
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Affiliation(s)
- Angela Peron
- Child Neuropsychiatry Unit - Epilepsy Center, San Paolo Hospital, Milan, Italy.,Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.,Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Francesca La Briola
- Child Neuropsychiatry Unit - Epilepsy Center, San Paolo Hospital, Milan, Italy
| | - Elisabetta Merati
- Child Neuropsychiatry Unit - Epilepsy Center, San Paolo Hospital, Milan, Italy.,Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | | | | | | | - Aglaia Vignoli
- Child Neuropsychiatry Unit - Epilepsy Center, San Paolo Hospital, Milan, Italy.,Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Roberto Ciccone
- Microgenomics srl, Pavia, Italy.,Biology and Medical Genetics Unit, Department of Molecular Medicine, Università di Pavia, Pavia, Italy
| | - Maria Paola Canevini
- Child Neuropsychiatry Unit - Epilepsy Center, San Paolo Hospital, Milan, Italy.,Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
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25
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Heimer G, van Woerden GM, Barel O, Marek-Yagel D, Kol N, Munting JB, Borghei M, Atawneh OM, Nissenkorn A, Rechavi G, Anikster Y, Elgersma Y, Kushner SA, Ben Zeev B. Netrin-G2 dysfunction causes a Rett-like phenotype with areflexia. Hum Mutat 2019; 41:476-486. [PMID: 31692205 DOI: 10.1002/humu.23945] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/17/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022]
Abstract
We describe the underlying genetic cause of a novel Rett-like phenotype accompanied by areflexia in three methyl-CpG-binding protein 2-negative individuals from two unrelated families. Discovery analysis was performed using whole-exome sequencing followed by Sanger sequencing for validation and segregation. Functional studies using short-hairpin RNA for targeted gene knockdown were implemented by the transfection of mouse cultured primary hippocampal neurons and in vivo by in utero electroporation. All patients shared a common homozygous frameshift mutation (chr9:135073515, c.376dupT, p.(Ser126PhefsTer241)) in netrin-G2 (NTNG2, NM_032536.3) with predicted nonsense-mediated decay. The mutation fully segregated with the disease in both families. The knockdown of either NTNG2 or the related netrin-G family member NTNG1 resulted in severe neurodevelopmental defects of neuronal morphology and migration. While NTNG1 has previously been linked to a Rett syndrome (RTT)-like phenotype, this is the first description of a RTT-like phenotype caused by NTNG2 mutation. Netrin-G proteins have been shown to be required for proper axonal guidance during early brain development and involved in N-methyl- d-aspartate-mediated synaptic transmission. Our results demonstrating that knockdown of murine NTNG2 causes severe impairments of neuronal morphology and cortical migration are consistent with those of RTT animal models and the shared neurodevelopmental phenotypes between the individuals described here and typical RTT patients.
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Affiliation(s)
- Gali Heimer
- Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Ramat Gan, Israel.,The Pinchas Borenstein Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Ramat Gan, Israel.,The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Geeske M van Woerden
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Ortal Barel
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel.,Wohl Institute for Translational Medicine, Sheba Medical Center, Ramat Gan, Israel
| | - Dina Marek-Yagel
- Metabolic Disease Unit, Edmond and Lily Safra Children's Hospital, The Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Nitzan Kol
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel.,Wohl Institute for Translational Medicine, Sheba Medical Center, Ramat Gan, Israel
| | - Johannes B Munting
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Minoeshka Borghei
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - Andreea Nissenkorn
- Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Ramat Gan, Israel.,The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gideon Rechavi
- The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel.,Wohl Institute for Translational Medicine, Sheba Medical Center, Ramat Gan, Israel
| | - Yair Anikster
- The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Metabolic Disease Unit, Edmond and Lily Safra Children's Hospital, The Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Ype Elgersma
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Steven A Kushner
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, Rotterdam, The Netherlands.,Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Bruria Ben Zeev
- Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Ramat Gan, Israel.,The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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