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Chengyan L, Chupeng X, You W, Yinhui C, Binglong H, Dang A, Ling L, Chuan T. Identification of genetic causes in children with unexplained epilepsy based on trio-whole exome sequencing. Clin Genet 2024; 106:140-149. [PMID: 38468460 DOI: 10.1111/cge.14519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/13/2024]
Abstract
Genotype and clinical phenotype analyses of 128 children were performed based on whole exome sequencing (WES), providing a reference for the provision of genetic counseling and the precise diagnosis and treatment of epilepsy. A total of 128 children with unexplained epilepsy were included in this study, and all their clinical data were analyzed. The children's treatments, epilepsy control, and neurodevelopmental levels were regularly followed up every 3 months. The genetic diagnostic yield of the 128 children with epilepsy is 50.8%, with an SNV diagnostic yield of 39.8% and a CNV diagnostic yield of 12.5%. Among the 128 children with epilepsy, 57.0% had onset of epilepsy in infancy, 25.8% have more than two clinical seizure forms, 62.5% require two or more anti-epileptic drug treatments, and 72.7% of the children have varying degrees of psychomotor development retardation. There are significant differences between ages of onset, neurodevelopmental levels and the presence of drug resistance in the genetic diagnostic yield (all p < 0.05). The 52 pathogenic/likely pathogenic SNVs involve 31 genes, with genes encoding ion channels having the largest number of mutations (30.8%). There were 16 cases of pathogenic/possibly pathogenic CNVs, among which the main proportions of CNVs were located in chromosome 15 and chromosome 16. Trio-WES is an essential tool for the genetic diagnosis of unexplained epilepsy, with a genetic diagnostic yield of up to 50.8%. Early genetic testing can provide an initiate appropriate therapies and accurate molecular diagnosis.
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Affiliation(s)
- Li Chengyan
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Xue Chupeng
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
- Department of Pediatrics, Shantou Central Hospital, Shantou, People's Republic of China
| | - Wang You
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Chen Yinhui
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Huang Binglong
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Ao Dang
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Liu Ling
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Tian Chuan
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
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The role of copy number variants in the genetic architecture of common familial epilepsies. Epilepsia 2024; 65:792-804. [PMID: 38101940 PMCID: PMC10948303 DOI: 10.1111/epi.17860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
OBJECTIVE Copy number variants (CNVs) contribute to genetic risk and genetic etiology of both rare and common epilepsies. Whereas many studies have explored the role of CNVs in sporadic or severe cases, fewer have been done in familial generalized and focal epilepsies. METHODS We analyzed exome sequence data from 267 multiplex families and 859 first-degree relative pairs with a diagnosis of genetic generalized epilepsies or nonacquired focal epilepsies to predict CNVs. Validation and segregation studies were performed using an orthogonal method when possible. RESULTS We identified CNVs likely to contribute to epilepsy risk or etiology in the probands of 43 of 1116 (3.9%) families, including known recurrent CNVs (16p13.11 deletion, 15q13.3 deletion, 15q11.2 deletion, 16p11.2 duplication, 1q21.1 duplication, and 5-Mb duplication of 15q11q13). We also identified CNVs affecting monogenic epilepsy genes, including four families with CNVs disrupting the DEPDC5 gene, and a de novo deletion of HNRNPU in one affected individual from a multiplex family. Several large CNVs (>500 kb) of uncertain clinical significance were identified, including a deletion in 18q, a large duplication encompassing the SCN1A gene, and a 15q13.3 duplication (BP4-BP5). SIGNIFICANCE The overall CNV landscape in common familial epilepsies is similar to that of sporadic epilepsies, with large recurrent deletions at 15q11, 15q13, and 16p13 contributing in 2.5%-3% of families. CNVs that interrupt known epilepsy genes and rare, large CNVs were also identified. Multiple etiologies were found in a subset of families, emphasizing the importance of genetic testing for multiple affected family members. Rare CNVs found in a single proband remain difficult to interpret and require larger cohorts to confirm their potential role in disease. Overall, our work indicates that CNVs contribute to the complex genetic architecture of familial generalized and focal epilepsies, supporting the role for clinical testing in affected individuals.
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Mastrangelo M, Manti F, Ricciardi G, Bove R, Greco C, Tolve M, Pisani F. The burden of epilepsy on long-term outcome of genetic developmental and epileptic encephalopathies: A single tertiary center longitudinal retrospective cohort study. Epilepsy Behav 2024; 152:109670. [PMID: 38335860 DOI: 10.1016/j.yebeh.2024.109670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/11/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
BACKGROUND This retrospective cohort analysis highlighted neurodevelopmental outcome predictors of genetic developmental and epileptic encephalopathies (DEE). PATIENTS AND METHODS Patients' demographic, clinical and molecular genetics data were collected. All patients underwent clinical, developmental, and neuropsychological assessments. RESULTS We recruited 100 participants (53 males, 47 females) with a mean follow-up lasting 10.46 ± 8.37 years. Age at epilepsy-onset was predictive of poor adaptive and cognitive functions (VABS-II score, r = 0.350, p = 0.001; BRIEF control subscale, r = -0.253; p = 0.031). Duration of epilepsy correlated negatively with IQ (r = -0.234, p = 0.019) and VABS-II score (r = -0.367, p = 0.001). Correlations were found between delayed/lacking EEG maturation/organization and IQ (r = 0.587, p = 0.001), VABS-II score (r = 0.658, p = 0.001), BRIEF-MI and BRIEF-GEC scores (r = -0.375, p = 0.001; r = -0.236, p = 0.033), ASEBA anxiety (r = -0.220, p = 0.047) and ADHD (r = -0.233, p = 0.035) scores. The number of antiseizure medications (ASMs) correlated with IQ (r = -0.414, p = 0.001), VABS-II (r = -0.496, p = 0.001), and BRIEF-MI (r = 0.294, p = 0.012) scores; while age at the beginning of therapy with ASEBA anxiety score (r = 0.272, p = 0.013). The occurrence of status epilepticus was associated with worse adaptive performances. The linear regression analysis model showed that delayed/lacking EEG maturation/organization had a significant influence on the IQ (R2 = 0.252, p < 0.001) and the BRIEF-GEC variability (R2 = 0.042, p = 0.036). The delayed/lacking EEG maturation/organization and the duration of epilepsy also had a significant influence on the VABS-II score (R2 = 0.455, p = 0.005). CONCLUSIONS Age at seizure-onset, EEG maturation/organization, duration of epilepsy, occurrence of status epilepticus, age at the introduction and number of ASMs used are reliable predictors of long-term outcomes in patients with genetic DEE.
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Affiliation(s)
- Mario Mastrangelo
- Department of Women/Child Health and Urological Science, Sapienza University of Rome, Rome, Italy; Unit of Child Neurology and Psychiatry, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy.
| | - Filippo Manti
- Unit of Child Neurology and Psychiatry, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy; Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Giacomina Ricciardi
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Rossella Bove
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Carlo Greco
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Manuela Tolve
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy; Department of Experimental Medicine, Sapienza University of Rome, Italy
| | - Francesco Pisani
- Unit of Child Neurology and Psychiatry, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy; Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
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Çapan ÖY, Yapıcı Z, Özbil M, Çağlayan HS. Exome data of developmental and epileptic encephalopathy patients reveals de novo and inherited pathologic variants in epilepsy-associated genes. Seizure 2024; 116:51-64. [PMID: 37353388 DOI: 10.1016/j.seizure.2023.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 06/04/2023] [Accepted: 06/10/2023] [Indexed: 06/25/2023] Open
Abstract
PURPOSE In Developmental and Epileptic Encephalopathies (DEEs), identifying the precise genetic factors guides the clinicians to apply the most appropriate treatment for the patient. Due to high locus heterogeneity, WES analysis is a promising approach for the genetic diagnosis of DEE. Therefore, the aim of the present study is to evaluate the utility of WES in the diagnosis and treatment of DEE patients. METHODS The exome data of 29 DEE patients were filtrated for destructive and missense mutations in 1896 epilepsy-related genes to detect the causative variants and examine the genotype-phenotype correlations. We performed Sanger sequencing with the available DNA samples to follow the co-segregation of the variants with the disease phenotype in the families. Also, the structural effects of p.Asn1053Ser, p.Pro120Ser and p.Glu1868Gly mutations on KCNMA1, NPC2, and SCN2A proteins, respectively, were evaluated by molecular dynamics (MD) and molecular docking simulations. RESULTS Out of 29, nine patients (31%) harbor pathological (P) or likely pathological (LP) mutations in SCN2A, KCNQ2, ATP1A2, KCNMA1, and MECP2 genes, and three patients have VUS variants (10%) in SCN1A and SCN2A genes. Sanger sequencing results indicated that three of the patients have de novo mutations while eight of them carry paternally and/or maternally inherited causative variants. MD and molecular docking simulations supported the destructive effects of the mutations on KCNMA1, NPC2, and SCN2A protein structures. CONCLUSION Herein we demonstrated the effectiveness of WES for DEE with high locus heterogeneity. Identification of the genetic etiology guided the clinicians to adjust the proper treatment for the patients.
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Affiliation(s)
- Özlem Yalçın Çapan
- Department of Medical Biology, Faculty of Medicine, Tekirdağ Namık Kemal University, Tekirdağ, Turkey; Department of Molecular Biology and Genetics, İstanbul Arel University, İstanbul, Turkey.
| | - Zuhal Yapıcı
- Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Mehmet Özbil
- Institute of Biotechnology, Gebze Technical University, Kocaeli, Turkiye
| | - Hande S Çağlayan
- Department of Molecular Biology and Genetics, Boğaziçi University, İstanbul, Turkey (formerly)
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Varadi G. Mechanism of Analgesia by Gabapentinoid Drugs: Involvement of Modulation of Synaptogenesis and Trafficking of Glutamate-Gated Ion Channels. J Pharmacol Exp Ther 2024; 388:121-133. [PMID: 37918854 DOI: 10.1124/jpet.123.001669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023] Open
Abstract
Gabapentinoids have clinically been used for treating epilepsy, neuropathic pain, and several other neurologic disorders for >30 years; however, the definitive molecular mechanism responsible for their therapeutic actions remained uncertain. The conventional pharmacological observation regarding their efficacy in chronic pain modulation is the weakening of glutamate release at presynaptic terminals in the spinal cord. While the α2/δ-1 subunit of voltage-gated calcium channels (VGCCs) has been identified as the primary drug receptor for gabapentinoids, the lack of consistent effect of this drug class on VGCC function is indicative of a minor role in regulating this ion channel's activity. The current review targets the efficacy and mechanism of gabapentinoids in treating chronic pain. The discovery of interaction of α2/δ-1 with thrombospondins established this protein as a major synaptogenic neuronal receptor for thrombospondins. Other findings identified α2/δ-1 as a powerful regulator of N-methyl-D-aspartate receptor (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) by potentiating the synaptic expression, a putative pathophysiological mechanism of neuropathic pain. Further, the interdependent interactions between thrombospondin and α2/δ-1 contribute to chronic pain states, while gabapentinoid ligands efficaciously reverse such pain conditions. Gabapentin normalizes and even blocks NMDAR and AMPAR synaptic targeting and activity elicited by nerve injury. SIGNIFICANCE STATEMENT: Gabapentinoid drugs are used to treat various neurological conditions including chronic pain. In chronic pain states, gene expression of cacnα2/δ-1 and thrombospondins are upregulated and promote aberrant excitatory synaptogenesis. The complex trait of protein associations that involve interdependent interactions between α2/δ-1 and thrombospondins, further, association of N-methyl-D-aspartate receptor and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor with the C-tail of α2/δ-1, constitutes a macromolecular signaling complex that forms the crucial elements for the pharmacological mode of action of gabapentinoids.
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Burk KC, Kaneko M, Quindipan C, Vu MH, Cepin MF, Santoro JD, Van Hirtum-Das M, Holder D, Raca G. Diagnostic Yield of Epilepsy-Genes Sequencing and Chromosomal Microarray in Pediatric Epilepsy. Pediatr Neurol 2024; 150:50-56. [PMID: 37979304 DOI: 10.1016/j.pediatrneurol.2023.10.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/26/2023] [Accepted: 10/19/2023] [Indexed: 11/20/2023]
Abstract
BACKGROUND Around 40% of individuals with epilepsy have an underlying identifiable genetic etiology. Common methods for epilepsy genetic testing are chromosomal microarray (CMA) and epilepsy-genes sequencing (EGS). Historically, CMA was the first-line test for patients with epilepsy, but recent studies have shown that EGS has a superior diagnostic yield. To further optimize testing algorithms for epilepsy, we compared these tests' diagnostic yields and explored how they are influenced by age of onset and phenotype complexity. METHODS Genetic test results from a cohort of patients with epilepsy were used to determine the diagnostic yield of CMA (n = 366) versus EGS (n = 370) for genetic epilepsy etiologies. Further analysis examined the probability of diagnostic results based on age of seizure onset and patients' phenotype complexity. RESULTS For patients who underwent CMA, causative variants were found in 28 of 366 cases (7.7%), and 60 of 366 patients (16.4%) had at least one variant of uncertain significance (VUS). For EGS, 65 of 370 (17.6%) cases had causative variants, whereas 155 of 370 (41.9%) had at least one VUS. EGS had a significantly higher diagnostic yield than CMA (odds ratio [OR] = 2.63, P < 0.001). This difference in diagnostic yield was further pronounced among patients with infantile seizure onset (OR = 4.69, P < 0.001) and patients with additional neurological findings (OR = 2.99, P < 0.001). CONCLUSION To minimize the time and resources required to reach a diagnosis, clinicians and insurers alike should consider using EGS as an initial diagnostic tool.
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Affiliation(s)
- Kelly C Burk
- Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Maki Kaneko
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Center for Personalized Medicine, Los Angeles, California
| | - Catherine Quindipan
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Center for Personalized Medicine, Los Angeles, California
| | - My H Vu
- Biostatistics Core, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California
| | - Maritza Feliz Cepin
- Division of Neurology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles
| | - Jonathan D Santoro
- Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, California; Division of Neurology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles
| | - Michele Van Hirtum-Das
- Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, California; Division of Neurology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles
| | - Deborah Holder
- Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, California; Division of Neurology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles
| | - Gordana Raca
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Center for Personalized Medicine, Los Angeles, California.
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Chaudhuri T, Hosur MV. Molecular modelling reveals how abundance of α4 sub-type in synaptic GABAR A receptor can lead to refractoriness toward GABA and BZ-type drugs. J Biomol Struct Dyn 2023:1-8. [PMID: 37948195 DOI: 10.1080/07391102.2023.2277858] [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: 08/16/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023]
Abstract
Epilepsy is a complex neurological disorder with genetic and acquired causes, and the drugs presently used to treat epilepsy are not effective in about 30% of the cases. Identification of the molecular mechanisms of resistance will help in the development of newer molecules for treatment. Recent clinical data indicate increased expression of α4- and γ2-containing synaptic GABARA receptors in patients of focal cortical dysplasia (FCD), which is associated with refractory epilepsy pathology. We have investigated, by molecular modelling and docking, the structure and ligand-binding efficiency of the α4-containing hetero-pentameric synaptic GABARA receptor. Though the overall conformation is similar to that of the α1-containing receptor, local conformational changes are seen due to differences between aligned α1 and α4 sub-type residues. The overlaps ALA209(α1)/PRO215(α4) and PHE73(α1)/TYR79(α4) have together caused conformational changes in ARG100(α4) (aligned with ARG94 in α1) thereby affecting key hydrogen bonding interactions with the inhibitory neurotransmitter GABA. This may influence the nature of seizures as strength of GABA-binding is known to affect the nature of Inhibitory Post-Synaptic Currents (IPSCs) from GABAergic neurons. The residue ARG135 (α4) aligns with the residue HIS129 (α1) in the benzodiazapine binding pocket. Molecular modelling also shows that a steric clash between benzodiazapine-type (BZ-type) drugs and ARG135 would reduce the binding of BZ-type drugs to α4-containing receptor. These two findings rationalize the observed association between over-expression of α4-containing synaptic GABARA receptors and refractory epilepsy pathology in FCD. The accurate three-dimensional geometry of the receptor-drug complex made available by these modelling studies will help in designing effective drugs.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Tanusree Chaudhuri
- Department of Natural Sciences and Engineering, National Institute of Advanced Studies, Bangalore, India
| | - M V Hosur
- Department of Natural Sciences and Engineering, National Institute of Advanced Studies, Bangalore, India
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Zhang Q, Forster-Gibson C, Bercovici E, Bernardo A, Ding F, Shen W, Langer K, Rex T, Kang JQ. Epilepsy plus blindness in microdeletion of GABRA1 and GABRG2 in mouse and human. Exp Neurol 2023; 369:114537. [PMID: 37703949 PMCID: PMC10591898 DOI: 10.1016/j.expneurol.2023.114537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
OBJECTIVE GABAA receptor subunit gene (GABR) mutations are significant causes of epilepsy, including syndromic epilepsy. This report for the first time, describes intractable epilepsy and blindness due to optic atrophy in our patient, who has a microdeletion of the GABRA1 and GABRG2 genes. We then characterized the molecular phenotypes and determined patho-mechanisms underlying the genotype-phenotype correlations in a mouse model who is haploinsufficient for both genes (Gabra1+/-/Gabrg2+/- mouse). METHODS Electroencephalography was conducted in both human and mice with the same gene loss. GABAA receptor expression was evaluated by biochemical and imaging approaches. Optic nerve atrophy was evaluated with fundus photography in human while electronic microscopy, visual evoked potential and electroretinography recordings were conducted in mice. RESULTS The patient has bilateral optical nerve atrophy. Mice displayed spontaneous seizures, reduced electroretinography oscillatory potential and reduced GABAA receptor α1, β2 and γ2 subunit expression in various brain regions. Electronic microscopy showed that mice also had optic nerve degeneration, as indicated by increased G-ratio, the ratio of the inner axonal diameter to the total outer diameter, suggesting impaired myelination of axons. More importantly, we identified that phenobarbital was the most effective anticonvulsant in mice and the patient's seizures were also controlled with phenobarbital after failing multiple anti-seizure drugs. CONCLUSIONS This study is the first report of haploinsufficiency of two GABR epilepsy genes and visual impairment due to altered axonal myelination and resultant optic nerve atrophy. The study suggests the far-reaching impact of GABR mutations and the translational significance of animal models with the same etiology.
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Affiliation(s)
- Qi Zhang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Cynthia Forster-Gibson
- Laboratory Medicine and Genetics, Trillium Health Partners, Mississauga and Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Canada
| | - Eduard Bercovici
- Division of Neurology, Faculty of Medicine, University of Toronto, Canada
| | - Alexandra Bernardo
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Katherine Langer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Tonia Rex
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Department of Pharmacology, Vanderbilt University, United States of America; Vanderbilt Brain Institute and Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN 37212, United States of America.
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LaFlamme CW, Rastin C, Sengupta S, Pennington HE, Russ-Hall SJ, Schneider AL, Bonkowski ES, Almanza Fuerte EP, Galey M, Goffena J, Gibson SB, Allan TJ, Nyaga DM, Lieffering N, Hebbar M, Walker EV, Darnell D, Olsen SR, Kolekar P, Djekidel N, Rosikiewicz W, McConkey H, Kerkhof J, Levy MA, Relator R, Lev D, Lerman-Sagie T, Park KL, Alders M, Cappuccio G, Chatron N, Demain L, Genevieve D, Lesca G, Roscioli T, Sanlaville D, Tedder ML, Hubshman MW, Ketkar S, Dai H, Worley KC, Rosenfeld JA, Chao HT, Neale G, Carvill GL, Wang Z, Berkovic SF, Sadleir LG, Miller DE, Scheffer IE, Sadikovic B, Mefford HC. Diagnostic Utility of Genome-wide DNA Methylation Analysis in Genetically Unsolved Developmental and Epileptic Encephalopathies and Refinement of a CHD2 Episignature. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.10.11.23296741. [PMID: 37873138 PMCID: PMC10592992 DOI: 10.1101/2023.10.11.23296741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Sequence-based genetic testing currently identifies causative genetic variants in ∼50% of individuals with developmental and epileptic encephalopathies (DEEs). Aberrant changes in DNA methylation are implicated in various neurodevelopmental disorders but remain unstudied in DEEs. Rare epigenetic variations ("epivariants") can drive disease by modulating gene expression at single loci, whereas genome-wide DNA methylation changes can result in distinct "episignature" biomarkers for monogenic disorders in a growing number of rare diseases. Here, we interrogate the diagnostic utility of genome-wide DNA methylation array analysis on peripheral blood samples from 516 individuals with genetically unsolved DEEs who had previously undergone extensive genetic testing. We identified rare differentially methylated regions (DMRs) and explanatory episignatures to discover causative and candidate genetic etiologies in 10 individuals. We then used long-read sequencing to identify DNA variants underlying rare DMRs, including one balanced translocation, three CG-rich repeat expansions, and two copy number variants. We also identify pathogenic sequence variants associated with episignatures; some had been missed by previous exome sequencing. Although most DEE genes lack known episignatures, the increase in diagnostic yield for DNA methylation analysis in DEEs is comparable to the added yield of genome sequencing. Finally, we refine an episignature for CHD2 using an 850K methylation array which was further refined at higher CpG resolution using bisulfite sequencing to investigate potential insights into CHD2 pathophysiology. Our study demonstrates the diagnostic yield of genome-wide DNA methylation analysis to identify causal and candidate genetic causes as ∼2% (10/516) for unsolved DEE cases.
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Lauerer RJ, Lerche H. Voltage-gated calcium channels in genetic epilepsies. J Neurochem 2023. [PMID: 37822150 DOI: 10.1111/jnc.15983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Voltage-gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation-transcription coupling, muscle contraction and excitation-exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease-specific therapies where applicable.
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Affiliation(s)
- Robert J Lauerer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
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Wu D, Wu Y, Lan Y, Lan S, Zhong Z, Li D, Zheng Z, Wang H, Ma L. Chromosomal Aberrations in Pediatric Patients With Moderate/Severe Developmental Delay/Intellectual Disability With Abundant Phenotypic Heterogeneities: A Single-Center Study. Pediatr Neurol 2023; 147:72-81. [PMID: 37566956 DOI: 10.1016/j.pediatrneurol.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/26/2023] [Accepted: 06/06/2023] [Indexed: 08/13/2023]
Abstract
BACKGROUND This study aimed to examine the clinical usefulness of chromosome microarray (CMA) for selective implementation in patients with unexplained moderate or severe developmental delay/intellectual disability (DD/ID) and/or combined with different dysphonic features in the Han Chinese population. METHODS We retrospectively analyzed data on 122 pediatric patients with unexplained isolated moderate/severe DD/ID with or without autism spectrum disorders, epilepsy, dystonia, and congenital abnormalities from a single-center neurorehabilitation clinic in southern China. RESULTS A total of 46 probands (37.7%) had abnormal CMA results among the 122 study patients. With the exclusion of aneuploidies, uniparental disomies, and multiple homozygotes, 37 patients harbored 39 pathogenic copy number variations (pCNVs) (median [interquartile range] size: 3.57 [1.6 to 7.1] Mb; 33 deletions and 6 duplications), enriched in chromosomes 5, 7, 15, 17, and 22, with a markedly high prevalence of Angelman/Prader-Willi syndrome (24.3% [nine of 37]). Three rare deletions in the regions 5q33.2q34, 17p13.2, and 13q33.2 were reported, with specific delineation of clinical phenotypes. The frequencies of pCNVs were 18%, 33.3%, 38.89%, 41.67%, and 100% for patients with 1, 2, 3, 4, and 5 study phenotypes, respectively; patients with more concomitant abnormalities in the heart, brain, craniofacial region, and/or other organs had a higher CMA diagnostic yield and pCNV prevalence (P < 0.05). CONCLUSIONS Clinical application of CMA as a first-tier test among patients with moderate/severe DD/ID combined with congenital structural anomalies improved diagnostic yields and the quality of clinical management in this series of patients.
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Affiliation(s)
- Dan Wu
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China; Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Yi Wu
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yulong Lan
- Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia; Department of Cardiology, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Shaocong Lan
- Guangdong Medical College, Zhanjiang, Guangdong, China
| | - Zhiwei Zhong
- Department of Neurosurgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Duo Li
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Zexin Zheng
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Hongwu Wang
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
| | - Lian Ma
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China; Department of Hematology and Oncology, Shenzhen Children's Hospital of China Medical University, Shenzhen, Guangdong, China; Shenzhen Public Service Platform of Molecular Medicine in Pediatric Hematology and Oncology, Shenzhen, Guangdong, China; Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University (The Women and Children's Hospital of Guangzhou Medical University), Guangzhou, Guangdong, China.
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12
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Montanucci L, Lewis-Smith D, Collins RL, Niestroj LM, Parthasarathy S, Xian J, Ganesan S, Macnee M, Brünger T, Thomas RH, Talkowski M, Helbig I, Leu C, Lal D. Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals. Nat Commun 2023; 14:4392. [PMID: 37474567 PMCID: PMC10359300 DOI: 10.1038/s41467-023-39539-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 06/16/2023] [Indexed: 07/22/2023] Open
Abstract
Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice.
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Affiliation(s)
- Ludovica Montanucci
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA
| | - David Lewis-Smith
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- Clinical Neurosciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ryan L Collins
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, USA
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA
| | | | - Shridhar Parthasarathy
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Julie Xian
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Shiva Ganesan
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Marie Macnee
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Tobias Brünger
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Rhys H Thomas
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- Clinical Neurosciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Michael Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, USA
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA
| | - Ingo Helbig
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA.
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T, Cambridge, MA, USA.
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, US.
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA.
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA.
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T, Cambridge, MA, USA.
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, US.
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13
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Wu Y, Wu D, Lan Y, Lan S, Li D, Zheng Z, Wang H, Ma L. Case report: Sex-specific characteristics of epilepsy phenotypes associated with Xp22.31 deletion: a case report and review. Front Genet 2023; 14:1025390. [PMID: 37347056 PMCID: PMC10280017 DOI: 10.3389/fgene.2023.1025390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 05/23/2023] [Indexed: 06/23/2023] Open
Abstract
Deletion in the Xp22.31 region is increasingly suggested to be involved in the etiology of epilepsy. Little is known regarding the genomic and clinical delineations of X-linked epilepsy in the Chinese population or the sex-stratified difference in epilepsy characteristics associated with deletions in the Xp22.31 region. In this study, we reported two siblings with a 1.69 Mb maternally inherited microdeletion at Xp22.31 involving the genes VCX3A, HDHD1, STS, VCX, VCX2, and PNPLA4 presenting with easily controlled focal epilepsy and language delay with mild ichthyosis in a Chinese family with a traceable 4-generation history of skin ichthyosis. Both brain magnetic resonance imaging results were normal, while EEG revealed epileptic abnormalities. We further performed an exhaustive literature search, documenting 25 patients with epilepsy with gene defects in Xp22.31, and summarized the epilepsy heterogeneities between sexes. Males harboring the Xp22.31 deletion mainly manifested with child-onset, easily controlled focal epilepsy accompanied by X-linked ichthyosis; the deletions were mostly X-linked recessive, with copy number variants (CNVs) in the classic region of deletion (863.38 kb-2 Mb). In contrast, epilepsy in females tended to be earlier-onset, and relatively refractory, with pathogenic CNV sizes varying over a larger range (859 kb-56.36 Mb); the alterations were infrequently inherited and almost combined with additional CNVs. A candidate region encompassing STS, HDHD1, and MIR4767 was the likely pathogenic epilepsy-associated region. This study filled in the knowledge gap regarding the genomic and clinical delineations of X-linked recessive epilepsy in the Chinese population and extends the understanding of the sex-specific characteristics of Xp22.31 deletion in regard to epilepsy.
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Affiliation(s)
- Yi Wu
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Dan Wu
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
- Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Yulong Lan
- Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Department of Cardiology, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Shaocong Lan
- Department of clinical Medicine, Guangdong Medical University, Zhanjiang, China
| | - Duo Li
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Zexin Zheng
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Hongwu Wang
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Lian Ma
- Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, China
- Department of Hematology and Oncology, Shenzhen Children’s Hospital of China Medical University, Shenzhen, China
- Shenzhen Public Service Platform of Molecular Medicine in Pediatric Hematology and Oncology, Shenzhen, China
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University (The Women and Children’s Hospital of Guangzhou Medical University), Guangzhou, China
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14
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Chang YT, Hong SY, Lin WD, Lin CH, Lin SS, Tsai FJ, Chou IC. Genetic Testing in Children with Developmental and Epileptic Encephalopathies: A Review of Advances in Epilepsy Genomics. CHILDREN 2023; 10:children10030556. [PMID: 36980114 PMCID: PMC10047509 DOI: 10.3390/children10030556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
Advances in disease-related gene discovery have led to tremendous innovations in the field of epilepsy genetics. Identification of genetic mutations that cause epileptic encephalopathies has opened new avenues for the development of targeted therapies. Clinical testing using extensive gene panels, exomes, and genomes is currently accessible and has resulted in higher rates of diagnosis and better comprehension of the disease mechanisms underlying the condition. Children with developmental disabilities have a higher risk of developing epilepsy. As our understanding of the mechanisms underlying encephalopathies and epilepsies improves, there may be greater potential to develop innovative therapies tailored to an individual’s genotype. This article provides an overview of the significant progress in epilepsy genomics in recent years, with a focus on developmental and epileptic encephalopathies in children. The aim of this review is to enhance comprehension of the clinical utilization of genetic testing in this particular patient population. The development of effective and precise therapeutic strategies for epileptic encephalopathies may be facilitated by a comprehensive understanding of their molecular pathogenesis.
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Affiliation(s)
- Yu-Tzu Chang
- School of Post Baccalaureate Chinese Medicine, China Medical University, Taichung 40447, Taiwan; (Y.-T.C.)
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
| | - Syuan-Yu Hong
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
- Department of Medicine, School of Medicine, China Medical University, Taichung 40447, Taiwan
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40447, Taiwan
| | - Wei-De Lin
- School of Post Baccalaureate Chinese Medicine, China Medical University, Taichung 40447, Taiwan; (Y.-T.C.)
- Department of Medical Research, China Medical University Hospital, Taichung 40447, Taiwan
| | - Chien-Heng Lin
- Division of Pediatric Pulmonology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
- Department of Biomedical Imaging and Radiological Science, College of Medicine, China Medial University, Taichung 40447, Taiwan
| | - Sheng-Shing Lin
- School of Post Baccalaureate Chinese Medicine, China Medical University, Taichung 40447, Taiwan; (Y.-T.C.)
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
| | - Fuu-Jen Tsai
- Department of Medical Research, China Medical University Hospital, Taichung 40447, Taiwan
- Division of Genetics and Metabolism, China Medical University Children’s Hospital, Taichung 40447, Taiwan
- Department of Medical Genetics, China Medical University Hospital, Taichung 40447, Taiwan
- School of Chinese Medicine, China Medical University, Taichung 40447, Taiwan
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung 40447, Taiwan
| | - I-Ching Chou
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
- Graduate Institute of Integrated Medicine, China Medical University, Taichung 40447, Taiwan
- Correspondence: ; Tel.: +886-4-22052121
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15
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Brownstein CA, Douard E, Haynes RL, Koh HY, Haghighi A, Keywan C, Martin B, Alexandrescu S, Haas EA, Vargas SO, Wojcik MH, Jacquemont S, Poduri AH, Goldstein RD, Holm IA. Copy Number Variation and Structural Genomic Findings in 116 Cases of Sudden Unexplained Death between 1 and 28 Months of Age. ADVANCED GENETICS (HOBOKEN, N.J.) 2023; 4:2200012. [PMID: 36910592 PMCID: PMC10000288 DOI: 10.1002/ggn2.202200012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/31/2022] [Indexed: 11/09/2022]
Abstract
In sudden unexplained death in pediatrics (SUDP) the cause of death is unknown despite an autopsy and investigation. The role of copy number variations (CNVs) in SUDP has not been well-studied. Chromosomal microarray (CMA) data are generated for 116 SUDP cases with age at death between 1 and 28 months. CNVs are classified using the American College of Medical Genetics and Genomics guidelines and CNVs in our cohort are compared to an autism spectrum disorder (ASD) cohort, and to a control cohort. Pathogenic CNVs are identified in 5 of 116 cases (4.3%). Variants of uncertain significance (VUS) favoring pathogenic CNVs are identified in 9 cases (7.8%). Several CNVs are associated with neurodevelopmental phenotypes including seizures, ASD, developmental delay, and schizophrenia. The structural variant 47,XXY is identified in two cases (2/69 boys, 2.9%) not previously diagnosed with Klinefelter syndrome. Pathogenicity scores for deletions are significantly elevated in the SUDP cohort versus controls (p = 0.007) and are not significantly different from the ASD cohort. The finding of pathogenic or VUS favoring pathogenic CNVs, or structural variants, in 12.1% of cases, combined with the observation of higher pathogenicity scores for deletions in SUDP versus controls, suggests that CMA should be included in the genetic evaluation of SUDP.
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16
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Hessenberger M, Haddad S, Obermair GJ. Pathophysiological Roles of Auxiliary Calcium Channel α 2δ Subunits. Handb Exp Pharmacol 2023; 279:289-316. [PMID: 36598609 DOI: 10.1007/164_2022_630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
α2δ proteins serve as auxiliary subunits of voltage-gated calcium channels, which are essential components of excitable cells such as skeletal and heart muscles, nerve cells of the brain and the peripheral nervous system, as well as endocrine cells. Over the recent years, α2δ proteins have been identified as critical regulators of synaptic functions, including the formation and differentiation of synapses. These functions require signalling mechanisms which are partly independent of calcium channels. Hence, in light of these features it is not surprising that the genes encoding for the four α2δ isoforms have recently been linked to neurological and neurodevelopmental disorders including epilepsy, autism spectrum disorders, schizophrenia, and depressive and bipolar disorders. Despite the increasing number of identified disease-associated mutations, the underlying pathophysiological mechanisms are only beginning to emerge. However, a thorough understanding of the pathophysiological role of α2δ proteins ideally serves two purposes: first, it will contribute to our understanding of general pathological mechanisms in synaptic disorders. Second, it may support the future development of novel and specific treatments for brain disorders. In this context, it is noteworthy that the antiepileptic and anti-allodynic drugs gabapentin and pregabalin both act via binding to α2δ proteins and are among the top sold drugs for treating neuropathic pain. In this book chapter, we will discuss recent developments in our understanding of the functions of α2δ proteins, both as calcium channel subunits and as independent regulatory entities. Furthermore, we present and summarize recently identified and likely pathogenic mutations in the genes encoding α2δ proteins and discuss potential underlying pathophysiological consequences at the molecular and structural level.
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Affiliation(s)
- Manuel Hessenberger
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Sabrin Haddad
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gerald J Obermair
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria.
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Mastrangelo M, Salpietro V, Sullivan J. Editorial: Genetically determined epilepsies: Perspectives in the era of precision medicine. Front Neurol 2022; 13:1036846. [PMID: 36303564 PMCID: PMC9593089 DOI: 10.3389/fneur.2022.1036846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Affiliation(s)
- Mario Mastrangelo
- Division of Child and Adolescent Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
- Department of Neuroscience and Mental Health, Umberto I-Polyclinic Rome, Rome, Italy
- *Correspondence: Mario Mastrangelo
| | - Vincenzo Salpietro
- Department of Pediatrics, University of L'Aquila, L'Aquila, Italy
- Department of Neuromuscular Diseases, University College London, London, United Kingdom
| | - Joseph Sullivan
- Division of Epilepsy, Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
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18
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Moufawad El Achkar C, Rosen A, Kessler SK, Steinman KJ, Spence SJ, Ramocki M, Marco EJ, Green Snyder L, Spiro JE, Chung WK, Annapurna P, Sherr EH. Clinical Characteristics of Seizures and Epilepsy in Individuals With Recurrent Deletions and Duplications in the 16p11.2 Region. Neurol Genet 2022; 8:e200018. [PMID: 36531974 PMCID: PMC9756306 DOI: 10.1212/nxg.0000000000200018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 07/01/2022] [Indexed: 11/15/2022]
Abstract
Background and Objectives Deletions and duplications at 16p11.2 (BP4 to BP5; 29.5-30.1 Mb) have been associated with several neurodevelopmental and neuropsychiatric disorders including autism spectrum disorder, intellectual disability (ID), and schizophrenia. Seizures have also been reported in individuals with these particular copy number variants, but the epilepsy phenotypes have not been well-delineated. We aimed to systematically characterize the seizure types, epilepsy syndromes, and epilepsy severity in a large cohort of individuals with these 16p11.2 deletions and duplications. Methods The cohort of ascertained participants with the recurrent 16p11.2 copy number variant was assembled through the multicenter Simons Variation in Individuals Project. Detailed data on individuals identified as having a history of seizures were obtained using a semistructured phone interview and review of medical records, EEG, and MRI studies obtained clinically or as part of the Simons Variation in Individuals Project. Results Among 129 individuals with the 16p11.2 deletion, 31 (24%) had at least one seizure, including 23 (18%) who met criteria for epilepsy; 42% of them fit the phenotype of classic or atypical Self-limited (Familial) Infantile Epilepsy (Se(F)IE). Among 106 individuals with 16p11.2 duplications, 16 (15%) had at least one seizure, including 11 (10%) who met criteria for epilepsy. The seizure types and epilepsy syndromes were heterogeneous in this group. Most of the individuals in both the deletion and duplication groups had well-controlled seizures with subsequent remission. Pharmacoresistant epilepsy was uncommon. Seizures responded favorably to phenobarbital, carbamazepine, and oxcarbazepine in the deletion group, specifically in the Se(F)IE, and to various antiseizure medications in the duplication group. Discussion These findings delineate the spectrum of seizures and epilepsies in the recurrent 16p11.2 deletions and duplications and provide potential diagnostic, therapeutic, and prognostic information.
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Lee S, Kim BR, Kim YO. Rates of rare copy number variants in different circumstances among patients with genetic developmental and epileptic encephalopathy. Sci Prog 2022; 105:368504221131233. [PMID: 36217831 PMCID: PMC10481157 DOI: 10.1177/00368504221131233] [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] [Indexed: 11/05/2022]
Abstract
BACKGROUND Most patients with developmental and epileptic encephalopathy (DEE) have genetic etiology, which has been uncovered with different methods. Although chromosomal microarray analysis (CMA) has been broadly used in patients with DEE, data is still limited. METHODS Among 560 children (<18 years) who underwent CMA in our hospital between January 2013 and June 2021, 146 patients with developmental delay and recurrent seizures were screened. Patients with major brain abnormalities, metabolic abnormalities, and specific syndromes were excluded. The rate of rare copy number variants (CNVs) was estimated in total and according to seizure-onset age, relation to first seizure with the diagnosis of developmental delay, epilepsy syndromes, and organ anomalies. RESULTS Among the 110 patients enrolled, the rate of rare CNVs was 16.4%, varying by seizure-onset age: 33.3% in three neonates, 21.2% in 33 infants, 13.3% in 45 early childhood patients, 5.3% in 19 late childhood patients, and 30.0% in 10 adolescents. In relation to the first seizure with the diagnosis of developmental delay, the rates were 3.7%, 22.2%, and 12.5% in "before", "after", and "concurrent" subclasses, respectively. The rates of rare CNVs were 16.7% in "other predominantly focal or multifocal epilepsy", 28.6% in "other predominantly generalized epilepsy (PGE)", and 15.4% in West syndrome. The rates were 27.8% in minor brain anomalies, 37.5% in facial dysmorphism, and 22.2%, 20.0%, and 57.1% in endocrine, genitourinary and cardiovascular anomalies, respectively. CONCLUSION The rate of rare CNVs in patients with genetic DEE was 16.4% in total, which was higher in seizures occurring below the infantile period or after the diagnosis of developmental delay, in PGE, and in the presence of facial dysmorphism or cardiovascular anomalies.
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Affiliation(s)
- Sanghoon Lee
- Department of Pediatrics, Chonnam National University Children’s Hospital, Gwangju, Republic of Korea
| | - Bo Ram Kim
- Department of Pediatrics, Chonnam National University Hwasun Hospital, Hwasun, Republic of Korea
| | - Young Ok Kim
- Department of Pediatrics, Chonnam National University Children’s Hospital, Gwangju, Republic of Korea
- Department of Pediatrics, Chonnam National University Medical School, Gwangju, Republic of Korea
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Kwon CS, Wirrell EC, Jetté N. Autism Spectrum Disorder and Epilepsy. Neurol Clin 2022; 40:831-847. [DOI: 10.1016/j.ncl.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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21
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Moreau C, Tremblay F, Wolking S, Girard A, Laprise C, Hamdan FF, Michaud JL, Minassian BA, Cossette P, Girard SL. Assessment of burden and segregation profiles of CNVs in patients with epilepsy. Ann Clin Transl Neurol 2022; 9:1050-1058. [PMID: 35678011 PMCID: PMC9268881 DOI: 10.1002/acn3.51598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/12/2022] Open
Abstract
Objective Microdeletions are associated with different forms of epilepsy but show incomplete penetrance, which is not well understood. We aimed to assess whether unmasked variants or double CNVs could explain incomplete penetrance. Methods We analyzed copy number variants (CNVs) in 603 patients with four different subgroups of epilepsy and 945 controls. CNVs were called from genotypes and validated on whole‐genome (WGS) or whole‐exome sequences (WES). CNV burden difference between patients and controls was obtained by fitting a logistic regression. CNV burden was assessed for small and large (>1 Mb) deletions and duplications and for deletions overlapping different gene sets. Results Large deletions were enriched in genetic generalized epilepsies (GGE) compared to controls. We also found enrichment of deletions in epilepsy genes and hotspots for GGE. We did not find truncating or functional variants that could have been unmasked by the deletions. We observed a double CNV hit in two patients. One patient also carried a de novo deletion in the 22q11.2 hotspot. Interpretation We could corroborate previous findings of an enrichment of large microdeletions and deletions in epilepsy genes in GGE. We could also replicate that microdeletions show incomplete penetrance. However, we could not validate the hypothesis of unmasked variants nor the hypothesis of double CNVs to explain the incomplete penetrance. We found a de novo CNV on 22q11.2 that could be of interest. We also observed GGE families carrying a deletion on 15q13.3 hotspot that could be investigated in the Quebec founder population.
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Affiliation(s)
- Claudia Moreau
- Department of Fundamental Sciences, University of Quebec in Chicoutimi, Chicoutimi, Canada
| | - Frédérique Tremblay
- Department of Fundamental Sciences, University of Quebec in Chicoutimi, Chicoutimi, Canada
| | - Stefan Wolking
- Department of Neurology and Epileptology, University Hospital RWTH Aachen, Aachen, Germany
| | - Alexandre Girard
- Department of Fundamental Sciences, University of Quebec in Chicoutimi, Chicoutimi, Canada
| | - Catherine Laprise
- Department of Fundamental Sciences, University of Quebec in Chicoutimi, Chicoutimi, Canada
| | - Fadi F Hamdan
- CHU Sainte-Justine Research Center, Montreal, Canada.,Department of Pediatrics, University of Montreal, Montreal, Canada
| | - Jacques L Michaud
- CHU Sainte-Justine Research Center, Montreal, Canada.,Department of Neurosciences and Department of Pediatrics, University of Montreal, Montreal, Canada
| | - Berge A Minassian
- Department of Pediatrics, Hospital for Sick Children and University of Toronto, Toronto, Canada.,Department of Pediatrics, University of Texas Southwestern, Dallas, Texas, USA
| | - Patrick Cossette
- CHUM Research Center, Montreal, Canada.,Department of Neurosciences, University of Montreal, Montreal, Canada
| | - Simon L Girard
- Department of Fundamental Sciences, University of Quebec in Chicoutimi, Chicoutimi, Canada.,CERVO Research Center, Laval University, Quebec, Canada
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22
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Genetics and gene therapy in Dravet syndrome. Epilepsy Behav 2022; 131:108043. [PMID: 34053869 DOI: 10.1016/j.yebeh.2021.108043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/02/2021] [Accepted: 05/02/2021] [Indexed: 12/17/2022]
Abstract
Dravet syndrome is a well-established electro-clinical condition first described in 1978. A main genetic cause was identified with the discovery of a loss-of-function SCN1A variant in 2001. Mechanisms underlying the phenotypic variations have subsequently been a main topic of research. Various genetic modifiers of clinical severities have been elucidated through many rigorous studies on genotype-phenotype correlations and the recent advances in next generation sequencing technology. Furthermore, a deeper understanding of the regulation of gene expression and remarkable progress on genome-editing technology using the CRISPR-Cas9 system provide significant opportunities to overcome hurdles of gene therapy, such as enhancing NaV1.1 expression. This article reviews the current understanding of genetic pathology and the status of research toward the development of gene therapy for Dravet syndrome. This article is part of the Special Issue "Severe Infantile Epilepsies".
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23
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CfDNA Measurement as a Diagnostic Tool for the Detection of Brain Somatic Mutations in Refractory Epilepsy. Int J Mol Sci 2022; 23:ijms23094879. [PMID: 35563270 PMCID: PMC9102996 DOI: 10.3390/ijms23094879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/21/2022] [Accepted: 04/26/2022] [Indexed: 02/04/2023] Open
Abstract
Epilepsy is a neurological disorder that affects more than 50 million people. Its etiology is unknown in approximately 60% of cases, although the existence of a genetic factor is estimated in about 75% of these individuals. Hundreds of genes involved in epilepsy are known, and their number is increasing progressively, especially with next-generation sequencing techniques. However, there are still many cases in which the results of these molecular studies do not fully explain the phenotype of the patients. Somatic mutations specific to brain tissue could contribute to the phenotypic spectrum of epilepsy. Undetectable in the genomic DNA of blood cells, these alterations can be identified in cell-free DNA (cfDNA). We aim to review the current literature regarding the detection of somatic variants in cfDNA to diagnose refractory epilepsy, highlighting novel research directions and suggesting further studies.
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24
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Birca V, Myers KA. Genetic Generalized Epilepsy and Intrafamilial Phenotypic Variability with Distal 7q11.23 Deletion. Child Neurol Open 2022; 9:2329048X221093173. [PMID: 35481155 PMCID: PMC9036355 DOI: 10.1177/2329048x221093173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 11/15/2022] Open
Abstract
Background: Distal 7q11.23 deletions are variably associated with epilepsy, intellectual disability and neurobehavioural abnormalities. The relative importance of different genes in this region in contributing to different phenotypes is not clear, though HIP1 and YWHAG are both thought to play important roles. Patients and Methods: We performed thorough phenotyping on members of a family in which multiple members carried a relatively small 0.8 Mb distal 7q11.23 deletion, affecting 17 genes. Results: Two brothers and a half-brother had all inherited the 7q11.23 deletion from their mother. The eldest two both had global developmental impairment and genetic generalized epilepsy, involving absence, myoclonic or myoclonic-atonic seizures. There was no history of seizures in the mother or her youngest son, but both also had developmental impairment. Conclusion: Distal 7q11.23 deletions affecting HIP1 and YWHAG may cause developmental impairment and genetic generalized epilepsy, with considerable intrafamilial phenotypic variability.
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Affiliation(s)
- Veronica Birca
- Division of Child Neurology, Department of Pediatrics, McGill University, Montreal, Quebec, Canada
| | - Kenneth A. Myers
- Division of Child Neurology, Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Canada
- Department of Neurology & Neurosurgery, Montreal Children’s Hospital, McGill University, Montreal, Canada
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25
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Auwerx C, Lepamets M, Sadler MC, Patxot M, Stojanov M, Baud D, Mägi R, Porcu E, Reymond A, Kutalik Z, Metspalu A, Milani L, Mägi R, Nelis M. The individual and global impact of copy-number variants on complex human traits. Am J Hum Genet 2022; 109:647-668. [PMID: 35240056 PMCID: PMC9069145 DOI: 10.1016/j.ajhg.2022.02.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 02/09/2022] [Indexed: 12/25/2022] Open
Abstract
The impact of copy-number variations (CNVs) on complex human traits remains understudied. We called CNVs in 331,522 UK Biobank participants and performed genome-wide association studies (GWASs) between the copy number of CNV-proxy probes and 57 continuous traits, revealing 131 signals spanning 47 phenotypes. Our analysis recapitulated well-known associations (e.g., 1q21 and height), revealed the pleiotropy of recurrent CNVs (e.g., 26 and 16 traits for 16p11.2-BP4-BP5 and 22q11.21, respectively), and suggested gene functionalities (e.g., MARF1 in female reproduction). Forty-eight CNV signals (38%) overlapped with single-nucleotide polymorphism (SNP)-GWASs signals for the same trait. For instance, deletion of PDZK1, which encodes a urate transporter scaffold protein, decreased serum urate levels, while deletion of RHD, which encodes the Rhesus blood group D antigen, associated with hematological traits. Other signals overlapped Mendelian disorder regions, suggesting variable expressivity and broad impact of these loci, as illustrated by signals mapping to Rotor syndrome (SLCO1B1/3), renal cysts and diabetes syndrome (HNF1B), or Charcot-Marie-Tooth (PMP22) loci. Total CNV burden negatively impacted 35 traits, leading to increased adiposity, liver/kidney damage, and decreased intelligence and physical capacity. Thirty traits remained burden associated after correcting for CNV-GWAS signals, pointing to a polygenic CNV architecture. The burden negatively correlated with socio-economic indicators, parental lifespan, and age (survivorship proxy), suggesting a contribution to decreased longevity. Together, our results showcase how studying CNVs can expand biological insights, emphasizing the critical role of this mutational class in shaping human traits and arguing in favor of a continuum between Mendelian and complex diseases.
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Affiliation(s)
- Chiara Auwerx
- Center for Integrative Genomics, University of Lausanne, Lausanne 1015, Switzerland; Department of Computational Biology, University of Lausanne, Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland; University Center for Primary Care and Public Health, Lausanne 1010, Switzerland
| | - Maarja Lepamets
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia; Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu 51010, Estonia
| | - Marie C Sadler
- Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland; University Center for Primary Care and Public Health, Lausanne 1010, Switzerland
| | - Marion Patxot
- Department of Computational Biology, University of Lausanne, Lausanne 1015, Switzerland
| | - Miloš Stojanov
- Materno-fetal and Obstetrics Research Unit, Department Woman-Mother-Child, CHUV, Lausanne 1011, Switzerland
| | - David Baud
- Materno-fetal and Obstetrics Research Unit, Department Woman-Mother-Child, CHUV, Lausanne 1011, Switzerland
| | - Reedik Mägi
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu 51010, Estonia
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- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu 51010, Estonia
| | - Eleonora Porcu
- Center for Integrative Genomics, University of Lausanne, Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland; University Center for Primary Care and Public Health, Lausanne 1010, Switzerland
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, Lausanne 1015, Switzerland.
| | - Zoltán Kutalik
- Department of Computational Biology, University of Lausanne, Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland; University Center for Primary Care and Public Health, Lausanne 1010, Switzerland.
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26
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Tomasello DL, Kim JL, Khodour Y, McCammon JM, Mitalipova M, Jaenisch R, Futerman AH, Sive H. 16pdel lipid changes in iPSC-derived neurons and function of FAM57B in lipid metabolism and synaptogenesis. iScience 2022; 25:103551. [PMID: 34984324 PMCID: PMC8693007 DOI: 10.1016/j.isci.2021.103551] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 09/23/2021] [Accepted: 11/26/2021] [Indexed: 01/01/2023] Open
Abstract
The complex 16p11.2 deletion syndrome (16pdel) is accompanied by neurological disorders, including epilepsy, autism spectrum disorder, and intellectual disability. We demonstrated that 16pdel iPSC differentiated neurons from affected people show augmented local field potential activity and altered ceramide-related lipid species relative to unaffected. FAM57B, a poorly characterized gene in the 16p11.2 interval, has emerged as a candidate tied to symptomatology. We found that FAM57B modulates ceramide synthase (CerS) activity, but is not a CerS per se. In FAM57B mutant human neuronal cells and zebrafish brain, composition and levels of sphingolipids and glycerolipids associated with cellular membranes are disrupted. Consistently, we observed aberrant plasma membrane architecture and synaptic protein mislocalization, which were accompanied by depressed brain and behavioral activity. Together, these results suggest that haploinsufficiency of FAM57B contributes to changes in neuronal activity and function in 16pdel syndrome through a crucial role for the gene in lipid metabolism.
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Affiliation(s)
| | - Jiyoon L. Kim
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yara Khodour
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Maya Mitalipova
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anthony H. Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hazel Sive
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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27
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Ai J, Wang Y, Liu D, Fan D, Wang Q, Li T, Luan G, Wang P, An J. Genetic Factors in Rasmussen's Encephalitis Characterized by Whole-Exome Sequencing. Front Neurosci 2021; 15:744429. [PMID: 34675770 PMCID: PMC8523672 DOI: 10.3389/fnins.2021.744429] [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: 07/20/2021] [Accepted: 09/13/2021] [Indexed: 12/01/2022] Open
Abstract
Rasmussen’s encephalitis (RE) is a rare chronic neurological disorder characterized by unihemispheric brain atrophy and epileptic seizures. The mechanisms of RE are complex. Adaptive immunity, innate immunity and viral infection are all involved in the development of RE. However, there are few studies on the role of genetic factors in the mechanisms of RE. Thus, the objective of this study was to reveal the genetic factors in the mechanisms of RE. Whole-exome sequencing (WES) was performed in 15 RE patients. Ten patients with temporal lobe epilepsy (TLE), which is a common and frequently intractable seizure disorder, were used as the controls. Thirty-one non-silent single nucleotide variants (SNVs) affecting 16 genes were identified in the RE cases. The functions of the genes with SNVs were associated with antigen presentation, antiviral infection, epilepsy, schizophrenia and nerve cell regeneration. Genetic factors of RE were found first in this study. These results suggest that RE patients have congenital abnormalities in adaptive immunity and are susceptible to some harmful factors, which lead to polygenic abnormal disease.
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Affiliation(s)
- Junhong Ai
- Department of Microbiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Yisong Wang
- Department of Microbiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Dong Liu
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Dongying Fan
- Department of Microbiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Qiqi Wang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Tianfu Li
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Guoming Luan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Peigang Wang
- Department of Microbiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Jing An
- Department of Microbiology, School of Basic Medical Science, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
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28
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Trollmann R, Borggräfe I, Müller-Felber W, Brandl U. Pädiatrische epileptische Enzephalopathien mit Manifestation oberhalb des Neugeborenenalters: ein Up-date. KLIN NEUROPHYSIOL 2021. [DOI: 10.1055/a-1528-3511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
ZusammenfassungEntwicklungs-und epileptische Enzephalopathien manifestieren sich überwiegend bereits im Säuglings-und frühen Kleinkindesalter. Mit der neuen ILAE-Klassifikation der Epilepsien konnten epileptische Enzephalopathien sowohl hinsichtlich des elektroklinischen Phänotyps als auch des ätiologischen Spektrums und assoziierter Komorbiditäten genauer definiert werden. Einige elektroklinischer Entitäten wie das West-Syndrom oder das Dravet-Syndrom können auf der Basis ihres Genotyps inzwischen als spezifische Enzephalopathien klassifiziert werden. Das EEG stellt eine wichtige Zusatzdiagnostik in der Abklärung einer epileptischen Enzephalopathie dar. Es hat einen besonderen Stellenwert für die Diagnose von Komplikationen wie z. B. subklinischer Anfälle oder eines Status epilepticus sowie für ein adäquates Therapiemonitoring. Der Betrag fasst anhand ausgewählter pädiatrischer Epilepsiesyndrome aktuelle Aspekte zur Komplexität der pädiatrischen epileptischen Enzephalopathien und den Stellenwert der EEG-Diagnostik zusammen.
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Affiliation(s)
- Regina Trollmann
- Abteilung Neuropädiatrie und Sozialpädiatrisches Zentrum, Kinder-und Jugendklinik am Universitätsklinikum, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen
| | - Ingo Borggräfe
- Abteilung für Pädiatrische Neurologie, Entwicklungsneurologie und Sozialpädiatrie, Dr. von Haunersches Kinderspital, LMU Klinikum München, München
- Interdisziplinäres Epilepsiezentrum, LMU Klinikum München, München
| | - Wolfgang Müller-Felber
- Abteilung für Pädiatrische Neurologie, Entwicklungsneurologie und Sozialpädiatrie, Dr. von Haunersches Kinderspital, LMU Klinikum München, München
| | - Ulrich Brandl
- Klinik für Neuropädiatrie, Universitätsklinikum Jena, Jena
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29
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Umlai UKI, Bangarusamy DK, Estivill X, Jithesh PV. Genome sequencing data analysis for rare disease gene discovery. Brief Bioinform 2021; 23:6366880. [PMID: 34498682 DOI: 10.1093/bib/bbab363] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/24/2021] [Accepted: 08/17/2021] [Indexed: 12/14/2022] Open
Abstract
Rare diseases occur in a smaller proportion of the general population, which is variedly defined as less than 200 000 individuals (US) or in less than 1 in 2000 individuals (Europe). Although rare, they collectively make up to approximately 7000 different disorders, with majority having a genetic origin, and affect roughly 300 million people globally. Most of the patients and their families undergo a long and frustrating diagnostic odyssey. However, advances in the field of genomics have started to facilitate the process of diagnosis, though it is hindered by the difficulty in genome data analysis and interpretation. A major impediment in diagnosis is in the understanding of the diverse approaches, tools and datasets available for variant prioritization, the most important step in the analysis of millions of variants to select a few potential variants. Here we present a review of the latest methodological developments and spectrum of tools available for rare disease genetic variant discovery and recommend appropriate data interpretation methods for variant prioritization. We have categorized the resources based on various steps of the variant interpretation workflow, starting from data processing, variant calling, annotation, filtration and finally prioritization, with a special emphasis on the last two steps. The methods discussed here pertain to elucidating the genetic basis of disease in individual patient cases via trio- or family-based analysis of the genome data. We advocate the use of a combination of tools and datasets and to follow multiple iterative approaches to elucidate the potential causative variant.
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Affiliation(s)
- Umm-Kulthum Ismail Umlai
- Division of Genomics & Translational Biomedicine, College of Health & Life Sciences, Hamad Bin Khalifa University, B-147, Penrose House, PO Box 34110, Education City, Doha, Qatar
| | - Dhinoth Kumar Bangarusamy
- Division of Genomics & Translational Biomedicine, College of Health & Life Sciences, Hamad Bin Khalifa University, B-147, Penrose House, PO Box 34110, Education City, Doha, Qatar
| | - Xavier Estivill
- Quantitative Genomics Laboratories (qGenomics), Barcelona, Catalonia, Spain
| | - Puthen Veettil Jithesh
- Division of Genomics & Translational Biomedicine, College of Health & Life Sciences, Hamad Bin Khalifa University, B-147, Penrose House, PO Box 34110, Education City, Doha, Qatar
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30
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Turkdogan D, Turkyilmaz A, Sager G, Ozturk G, Unver O, Say M. Chromosomal microarray and exome sequencing in unexplained early infantile epileptic encephalopathies in a highly consanguineous population. Int J Neurosci 2021:1-18. [PMID: 34380004 DOI: 10.1080/00207454.2021.1967349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AIM To identify genetic causes for early infantile epileptic encephalopathies (EIEE) in Turkish children with mostly consanguineous parents. METHODS In a selected EIEE group (N = 59) based on results of nongenetic and initial genetic testing with unexplained etiology, 49 patients underwent array-based comparative genomic hybridization (aCGH) and 49 patients underwent whole exome sequencing (WES) including 39 with negative aCGH results and 10 with WES-only. RESULTS Diagnostic yield of aCGH and WES for pathogenic or likely pathogenic variants was 14.3% and 38.8%, respectively. Including de novo variants of uncertain significance linked to compatible phenotypes, increased the diagnostic yield of WES to 61.2%. Out of 38 positive variants, 18 (47.4%) were novel and 16 (42.1%) were de novo. Twenty-one (56.8%) patients had recessive variants inherited from mostly consanguineous healthy parents (85.7%). Fourteen (37.8%) of patients with diagnostic results had positive variants in established EIEE genes. Seizures started during neonatal period in 32.4% patients. Posture or movement disorders were comorbid with EIEE in 40.5% of diagnosed patients. We identified treatable metabolic disorders in 8.1% of patients and pathogenic variants in genes which support using targeted medicine in 19% of patients. CONCLUSIONS Detailed electro-clinical phenotyping led to expansion of some of the known phenotypes with non-neurological and neurological findings in addition to seizures, as well as suggestion of candidate genes (SEC24B, SLC16A2 and PRICKLE2) and a copy number variant (microduplication of Xp21.1p11.4). The high ratio of recessive inheritance could be important for family counseling.
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Affiliation(s)
- Dilsad Turkdogan
- Medical Faculty, Department of Pediatric Neurology, Marmara University, Pendik, Istanbul, Turkey
| | - Ayberk Turkyilmaz
- Medical Faculty, Department of Medical Genetics, Marmara University, Pendik, Istanbul, Turkey
| | - Gunes Sager
- Medical Faculty, Department of Pediatric Neurology, Marmara University, Pendik, Istanbul, Turkey
| | - Gulten Ozturk
- Medical Faculty, Department of Pediatric Neurology, Marmara University, Pendik, Istanbul, Turkey
| | - Olcay Unver
- Medical Faculty, Department of Pediatric Neurology, Marmara University, Pendik, Istanbul, Turkey
| | - Merve Say
- Bioinformatics, Private Practice, Kadıkoy, Istanbul, Turkey
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31
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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32
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Epilepsy Syndromes in the First Year of Life and Usefulness of Genetic Testing for Precision Therapy. Genes (Basel) 2021; 12:genes12071051. [PMID: 34356067 PMCID: PMC8307222 DOI: 10.3390/genes12071051] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/23/2021] [Accepted: 07/05/2021] [Indexed: 12/18/2022] Open
Abstract
The high pace of gene discovery has resulted in thrilling advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, or genomes are now increasingly available and have led to a significant higher diagnostic yield in early-onset epilepsies and enabled precision medicine approaches. These have been instrumental in providing insights into the pathophysiology of both early-onset benign and self-limited syndromes and devastating developmental and epileptic encephalopathies (DEEs). Genetic heterogeneity is seen in many epilepsy syndromes such as West syndrome and epilepsy of infancy with migrating focal seizures (EIMFS), indicating that two or more genetic loci produce the same or similar phenotypes. At the same time, some genes such as SCN2A can be associated with a wide range of epilepsy syndromes ranging from self-limited familial neonatal epilepsy at the mild end to Ohtahara syndrome, EIFMS, West syndrome, Lennox–Gastaut syndrome, or unclassifiable DEEs at the severe end of the spectrum. The aim of this study was to review the clinical and genetic heterogeneity associated with epilepsy syndromes starting in the first year of life including: Self-limited familial neonatal, neonatal-infantile or infantile epilepsies, genetic epilepsy with febrile seizures plus spectrum, myoclonic epilepsy in infancy, Ohtahara syndrome, early myoclonic encephalopathy, West syndrome, Dravet syndrome, EIMFS, and unclassifiable DEEs. We also elaborate on the advantages and pitfalls of genetic testing in such conditions. Finally, we describe how a genetic diagnosis can potentially enable precision therapy in monogenic epilepsies and emphasize that early genetic testing is a cornerstone for such therapeutic strategies.
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33
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Epileptic Mechanisms Shared by Alzheimer's Disease: Viewed via the Unique Lens of Genetic Epilepsy. Int J Mol Sci 2021; 22:ijms22137133. [PMID: 34281185 PMCID: PMC8268161 DOI: 10.3390/ijms22137133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 12/18/2022] Open
Abstract
Our recent work on genetic epilepsy (GE) has identified common mechanisms between GE and neurodegenerative diseases including Alzheimer's disease (AD). Although both disorders are seemingly unrelated and occur at opposite ends of the age spectrum, it is likely there are shared mechanisms and studies on GE could provide unique insights into AD pathogenesis. Neurodegenerative diseases are typically late-onset disorders, but the underlying pathology may have already occurred long before the clinical symptoms emerge. Pathophysiology in the early phase of these diseases is understudied but critical for developing mechanism-based treatment. In AD, increased seizure susceptibility and silent epileptiform activity due to disrupted excitatory/inhibitory (E/I) balance has been identified much earlier than cognition deficit. Increased epileptiform activity is likely a main pathology in the early phase that directly contributes to impaired cognition. It is an enormous challenge to model the early phase of pathology with conventional AD mouse models due to the chronic disease course, let alone the complex interplay between subclinical nonconvulsive epileptiform activity, AD pathology, and cognition deficit. We have extensively studied GE, especially with gene mutations that affect the GABA pathway such as mutations in GABAA receptors and GABA transporter 1. We believe that some mouse models developed for studying GE and insights gained from GE could provide unique opportunity to understand AD. These include the pathology in early phase of AD, endoplasmic reticulum (ER) stress, and E/I imbalance as well as the contribution to cognitive deficit. In this review, we will focus on the overlapping mechanisms between GE and AD, the insights from mutations affecting GABAA receptors, and GABA transporter 1. We will detail mechanisms of E/I imbalance and the toxic epileptiform generation in AD, and the complex interplay between ER stress, impaired membrane protein trafficking, and synaptic physiology in both GE and AD.
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34
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Carvill GL, Matheny T, Hesselberth J, Demarest S. Haploinsufficiency, Dominant Negative, and Gain-of-Function Mechanisms in Epilepsy: Matching Therapeutic Approach to the Pathophysiology. Neurotherapeutics 2021; 18:1500-1514. [PMID: 34648141 PMCID: PMC8608973 DOI: 10.1007/s13311-021-01137-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2021] [Indexed: 02/04/2023] Open
Abstract
This review summarizes the pathogenic mechanisms that underpin the monogenic epilepsies and discusses the potential of novel precision therapeutics to treat these disorders. Pathogenic mechanisms of epilepsy include recessive (null alleles), haploinsufficiency, imprinting, gain-of-function, and dominant negative effects. Understanding which pathogenic mechanism(s) that underlie each genetic epilepsy is pivotal to design precision therapies that are most likely to be beneficial for the patient. Novel therapeutics discussed include gene therapy, gene editing, antisense oligonucleotides, and protein replacement. Discussions are illustrated and reinforced with examples from the literature.
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Affiliation(s)
- Gemma L Carvill
- Departments of Neurology, Pharmacology and Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Tyler Matheny
- Department Biochemistry and Molecular Genetics, School of Medicine, RNA Bioscience Initiative, University of Colorado, PO Box 6511, Aurora, CO, USA
| | - Jay Hesselberth
- Department Biochemistry and Molecular Genetics, School of Medicine, RNA Bioscience Initiative, University of Colorado, PO Box 6511, Aurora, CO, USA
| | - Scott Demarest
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, USA.
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Liu L, Liu F, Wang Q, Xie H, Li Z, Lu Q, Wang Y, Zhang M, Zhang Y, Picker J, Cui X, Zou L, Chen X. Confirming the contribution and genetic spectrum of de novo mutation in infantile spasms: Evidence from a Chinese cohort. Mol Genet Genomic Med 2021; 9:e1689. [PMID: 33951346 PMCID: PMC8222834 DOI: 10.1002/mgg3.1689] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 01/21/2023] Open
Abstract
Objective We determined the yield, genetic spectrum, and actual origin of de novo mutations (DNMs) for infantile spasms (ISs) in a Chinese cohort. The efficacy of levetiracetam (LEV) for STXBP1‐related ISs was explored also. Methods Targeted sequencing of 153 epilepsy‐related candidate genes was applied to 289 Chinese patients with undiagnosed ISs. Trio‐based amplicon deep sequencing was used for all DNMs to distinguish somatic/mosaic mutations from germline ones. Results Total of 26 DNMs were identified from 289 recruited Chinese patients with undiagnosed ISs. Among them, 24 DNMs were interpreted as pathogenic mutations based on American College of Medical Genetics and Genomics guidelines, contributing to 8.3% (24/289) of diagnosis yield in the Chinese IS cohort. CDKL5 and STXBP1 are the top genes with recurrent DNMs, accounting for 3.1% (9/289) of yield. Further deep resequencing for the trio members showed that 22.7% (5/22) of DNMs are actually somatic in the proband or a parent. These somatic carriers presented milder seizure attacks than those with true germline DNMs. After treatment with LEV for half a year, three patients with DNM in STXBP1 showed improved clinical symptoms, including seizure‐free and normal electroencephalogram, except for a patient with a second DNM in DIAPH3. Significance Our study confirmed the contribution and genetic spectrum of DNMs in Chinese IS patients. Somatic mutation account for a quarter of DNMs in IS cases. Treatment with LEV improved the prognosis of STXBP1‐related ISs.
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Affiliation(s)
- Liying Liu
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China
| | - Fang Liu
- Graduate School of Peking, Union Medical College, Beijing, China.,Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, China
| | - Qiuhong Wang
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China
| | - Hua Xie
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, China
| | - Zhengchang Li
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, China
| | - Qian Lu
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Yangyang Wang
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China
| | - Mengna Zhang
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China
| | - Yu Zhang
- Department of Lab Center, Capital Institute of Pediatrics, Beijing, China
| | - Jonathan Picker
- Division of Genetics & Genomics (Department of Medicine) and Department of Child & Adolescent Psychiatry, Boston Children's Hospital, Boston, MA, USA
| | - Xiaodai Cui
- Department of Lab Center, Capital Institute of Pediatrics, Beijing, China
| | - Liping Zou
- Department of Pediatrics, The First Medical Center of Chinese, PLA General Hospital, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Xiaoli Chen
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, China.,Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
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John A, Ng-Cordell E, Hanna N, Brkic D, Baker K. The neurodevelopmental spectrum of synaptic vesicle cycling disorders. J Neurochem 2021; 157:208-228. [PMID: 32738165 DOI: 10.1111/jnc.15135] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe and discuss neurodevelopmental phenotypes arising from rare, high penetrance genomic variants which directly influence synaptic vesicle cycling (SVC disorders). Pathogenic variants in each SVC disorder gene lead to disturbance of at least one SVC subprocess, namely vesicle trafficking (e.g. KIF1A and GDI1), clustering (e.g. TRIO, NRXN1 and SYN1), docking and priming (e.g. STXBP1), fusion (e.g. SYT1 and PRRT2) or re-uptake (e.g. DNM1, AP1S2 and TBC1D24). We observe that SVC disorders share a common set of neurological symptoms (movement disorders, epilepsies), cognitive impairments (developmental delay, intellectual disabilities, cerebral visual impairment) and mental health difficulties (autism, ADHD, psychiatric symptoms). On the other hand, there is notable phenotypic variation between and within disorders, which may reflect selective disruption to SVC subprocesses, spatiotemporal and cell-specific gene expression profiles, mutation-specific effects, or modifying factors. Understanding the common cellular and systems mechanisms underlying neurodevelopmental phenotypes in SVC disorders, and the factors responsible for variation in clinical presentations and outcomes, may translate to personalized clinical management and improved quality of life for patients and families.
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Affiliation(s)
- Abinayah John
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Elise Ng-Cordell
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Nancy Hanna
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Diandra Brkic
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Morrison-Levy N, Borlot F, Jain P, Whitney R. Early-Onset Developmental and Epileptic Encephalopathies of Infancy: An Overview of the Genetic Basis and Clinical Features. Pediatr Neurol 2021; 116:85-94. [PMID: 33515866 DOI: 10.1016/j.pediatrneurol.2020.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 12/19/2022]
Abstract
Our current knowledge of genetically determined forms of epilepsy has shortened the diagnostic pathway usually experienced by the families of infants diagnosed with early-onset developmental and epileptic encephalopathies. Genetic causes can be found in up to 80% of infants presenting with early-onset developmental and epileptic encephalopathies, often in the context of an uneventful perinatal history and with no clear underlying brain abnormalities. Although current disease-specific therapies remain limited and patient outcomes are often guarded, a genetic diagnosis may lead to early therapeutic intervention using new and/or repurposed therapies. In this review, an overview of epilepsy genetics, the indications for genetic testing in infants, the advantages and limitations of each test, and the challenges and ethical implications of genetic testing are discussed. In addition, the following causative genes associated with early-onset developmental and epileptic encephalopathies are discussed in detail: KCNT1, KCNQ2, KCNA2, SCN2A, SCN8A, STXBP1, CDKL5, PIGA, SPTAN1, and GNAO1. The epilepsy phenotypes, comorbidities, electroencephalgraphic findings, neuroimaging findings, and potential targeted therapies for each gene are reviewed.
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Affiliation(s)
| | - Felippe Borlot
- Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Puneet Jain
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, Ontario, Canada.
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Abstract
PURPOSE OF REVIEW To review the evolution of the concept of epileptic encephalopathy during the course of past years and analyze how the current definition might impact on both clinical practice and research. RECENT FINDINGS Developmental delay in children with epilepsy could be the expression of the cause, consequence of intense epileptiform activity (seizures and EEG abnormalities), or because of the combination of both factors. Therefore, the current International League Against Epilepsy classification identified three electroclinical entities that are those of developmental encephalopathy, epileptic encephalopathy, and developmental and epileptic encephalopathy (DEE). Many biological pathways could be involved in the pathogenesis of DEEs. DNA repair, transcriptional regulation, axon myelination, metabolite and ion transport, and peroxisomal function could all be involved in DEE. Also, epilepsy and epileptiform discharges might impact on cognition via several mechanisms, although they are not fully understood. SUMMARY The correct and early identification of cause in DEE might increase the chances of a targeted treatment regimen. Interfering with neurobiological processes of the disease will be the most successful way in order to improve both the cognitive disturbances and epilepsy that are the key features of DEE.
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Albuz B, Ozdemir O, Silan F. The high frequency of chromosomal copy number variations and candidate genes in epilepsy patients. Clin Neurol Neurosurg 2021; 202:106487. [PMID: 33484953 DOI: 10.1016/j.clineuro.2021.106487] [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: 07/09/2020] [Revised: 11/29/2020] [Accepted: 01/07/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Epilepsy is a chronic brain disease and is estimated to affect more than 50 million people worldwide.Epilepsy is a polygenic and multifactorial disease.Genetic causes play a major role in 40-60 % of all epilepsies.Copy number variations(CNVs) have been reported in approximately 5-12 % of patients with different types of epilepsy.Here we aimed to determine the diagnostic yield of the aCGH in epilepsy and to reveal new candidate genes and CNVs by analyzing aCGH data retrospectively. METHODS The clinical data of 80 patients with the diagnosis of epilepsy were examined retrospectively and the raw data of aCGH of these patients were reanalyzed in the light of current literature. RESULTS Pathogenic/likely pathogenic CNVs were detected in 14 of 80 patients and 12 of these CNVs (15 %) were associated with epilepsy phenotype. In addition, 18 CNVs in 16 different chromosomal loci that were evaluated as the variant of unknown clinical significance(VOUS). In four cases (5%), CNVs associated with epilepsy were less than 100 kb and these accounted for 13.3 % of all epilepsy associated CNVs. CONCLUSION The diagnostic yield of aCGH in epilepsy patients was found to be higher than most studies in the literature. MACROD2,ADGRB3(BAI3),SOX8,HIP1,PARK2 and TAFA2 genes were evaluated as potential epilepsy-related genes and NEDD9,RASAL2 and TNR genes thought to be the candidate genes for epilepsy. Our study showed that the diagnostic efficiency of aCGH in epilepsy is high and with more comprehensive studies, it will contribute to the elucidation of genes involved in genetic etiology in epilepsy patients.
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Affiliation(s)
- Burcu Albuz
- Department of Medical Genetics, Faculty of Medicine, Canakkale Onsekiz Mart University, 17020, Canakkale, Turkey.
| | - Ozturk Ozdemir
- Department of Medical Genetics, Faculty of Medicine, Canakkale Onsekiz Mart University, 17020, Canakkale, Turkey.
| | - Fatma Silan
- Department of Medical Genetics, Faculty of Medicine, Canakkale Onsekiz Mart University, 17020, Canakkale, Turkey.
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40
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Niestroj LM, Perez-Palma E, Howrigan DP, Zhou Y, Cheng F, Saarentaus E, Nürnberg P, Stevelink R, Daly MJ, Palotie A, Lal D. Epilepsy subtype-specific copy number burden observed in a genome-wide study of 17 458 subjects. Brain 2020; 143:2106-2118. [PMID: 32568404 DOI: 10.1093/brain/awaa171] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/17/2020] [Accepted: 04/06/2020] [Indexed: 11/14/2022] Open
Abstract
Cytogenic testing is routinely applied in most neurological centres for severe paediatric epilepsies. However, which characteristics of copy number variants (CNVs) confer most epilepsy risk and which epilepsy subtypes carry the most CNV burden, have not been explored on a genome-wide scale. Here, we present the largest CNV investigation in epilepsy to date with 10 712 European epilepsy cases and 6746 ancestry-matched controls. Patients with genetic generalized epilepsy, lesional focal epilepsy, non-acquired focal epilepsy, and developmental and epileptic encephalopathy were included. All samples were processed with the same technology and analysis pipeline. All investigated epilepsy types, including lesional focal epilepsy patients, showed an increase in CNV burden in at least one tested category compared to controls. However, we observed striking differences in CNV burden across epilepsy types and investigated CNV categories. Genetic generalized epilepsy patients have the highest CNV burden in all categories tested, followed by developmental and epileptic encephalopathy patients. Both epilepsy types also show association for deletions covering genes intolerant for truncating variants. Genome-wide CNV breakpoint association showed not only significant loci for genetic generalized and developmental and epileptic encephalopathy patients but also for lesional focal epilepsy patients. With a 34-fold risk for developing genetic generalized epilepsy, we show for the first time that the established epilepsy-associated 15q13.3 deletion represents the strongest risk CNV for genetic generalized epilepsy across the whole genome. Using the human interactome, we examined the largest connected component of the genes overlapped by CNVs in the four epilepsy types. We observed that genetic generalized epilepsy and non-acquired focal epilepsy formed disease modules. In summary, we show that in all common epilepsy types, 1.5-3% of patients carry epilepsy-associated CNVs. The characteristics of risk CNVs vary tremendously across and within epilepsy types. Thus, we advocate genome-wide genomic testing to identify all disease-associated types of CNVs.
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Affiliation(s)
- Lisa-Marie Niestroj
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, 50931, Germany
| | - Eduardo Perez-Palma
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | | | - Yadi Zhou
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Feixiong Cheng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA.,Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Elmo Saarentaus
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, FI-00014, Finland
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, 50931, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, 50931, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, 50931, Germany
| | - Remi Stevelink
- Department of Child Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark J Daly
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, FI-00014, Finland.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Aarno Palotie
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, FI-00014, Finland.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Dennis Lal
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, 50931, Germany.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195 USA
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Schneider AL, Myers CT, Muir AM, Calvert S, Basinger A, Perry MS, Rodan L, Helbig KL, Chambers C, Gorman KM, King MD, Donkervoort S, Soldatos A, Bönnemann CG, Spataro N, Gabau E, Arellano M, Cappuccio G, Brunetti-Pierri N, Rossignol E, Hamdan FF, Michaud JL, Balak C, Mefford HC, Scheffer IE. FBXO28 causes developmental and epileptic encephalopathy with profound intellectual disability. Epilepsia 2020; 62:e13-e21. [PMID: 33280099 DOI: 10.1111/epi.16784] [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: 07/10/2020] [Revised: 09/30/2020] [Accepted: 11/17/2020] [Indexed: 11/28/2022]
Abstract
Chromosome 1q41-q42 deletion syndrome is a rare cause of intellectual disability, seizures, dysmorphology, and multiple anomalies. Two genes in the 1q41-q42 microdeletion, WDR26 and FBXO28, have been implicated in monogenic disease. Patients with WDR26 encephalopathy overlap clinically with those with 1q41-q42 deletion syndrome, whereas only one patient with FBXO28 encephalopathy has been described. Seizures are a prominent feature of 1q41-q42 deletion syndrome; therefore, we hypothesized that pathogenic FBXO28 variants cause developmental and epileptic encephalopathies (DEEs). We describe nine new patients with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and analyze all 10 known cases to delineate the phenotypic spectrum. All patients had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features, albeit different to those typically seen in 1q41-q42 deletion syndrome and WDR26 encephalopathy. We distinguish FBXO28 encephalopathy from both of these disorders with more severe intellectual impairment, drug-resistant epilepsy, and hyperkinetic movement disorders.
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Affiliation(s)
- Amy L Schneider
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Candace T Myers
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | - Alison M Muir
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | - Sophie Calvert
- Department of Neurology, Queensland Children's Hospital, South Brisbane, Queensland, Australia
| | | | - M Scott Perry
- Justin Neurosciences Center, Cook Children's Medical Center, Fort Worth, TX, USA
| | - Lance Rodan
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Katherine L Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Chelsea Chambers
- Department of Neurosciences, University of Virginia, Charlottesville, VA, USA
| | - Kathleen M Gorman
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
| | - Mary D King
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Ariane Soldatos
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nino Spataro
- Genetics Laboratory, UDIAT-Centre Diagnostic, Parc Taulí University Hospital, Parc Taulí I3PT Research and Innovation Institute, University of Barcelona, Sabadell, Spain
| | - Elisabeth Gabau
- Paediatric Unit, Parc Taulí University Hospital, Parc Taulí I3PT Research and Innovation Institute, University of Barcelona, Sabadell, Spain
| | - Montserrat Arellano
- Neuropediatrics Unit, Pediatric Service, MutuaTerrassa University Hospital, Terrassa, Spain
| | - Gerarda Cappuccio
- Department of Translational Medicine, Federico II University, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, Federico II University, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | - Elsa Rossignol
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, Quebec, Canada.,Department of Neurosciences and Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Fadi F Hamdan
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, Quebec, Canada.,Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Jacques L Michaud
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, Quebec, Canada.,Department of Neurosciences and Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Christopher Balak
- Neurogenomics Division, Centre for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute, Phoenix, AZ, USA.,Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia.,Department of Paediatrics, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia.,Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
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Genetic Landscape of Common Epilepsies: Advancing towards Precision in Treatment. Int J Mol Sci 2020; 21:ijms21207784. [PMID: 33096746 PMCID: PMC7589654 DOI: 10.3390/ijms21207784] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/09/2020] [Accepted: 10/14/2020] [Indexed: 12/15/2022] Open
Abstract
Epilepsy, a neurological disease characterized by recurrent seizures, is highly heterogeneous in nature. Based on the prevalence, epilepsy is classified into two types: common and rare epilepsies. Common epilepsies affecting nearly 95% people with epilepsy, comprise generalized epilepsy which encompass idiopathic generalized epilepsy like childhood absence epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy and epilepsy with generalized tonic-clonic seizure on awakening and focal epilepsy like temporal lobe epilepsy and cryptogenic focal epilepsy. In 70% of the epilepsy cases, genetic factors are responsible either as single genetic variant in rare epilepsies or multiple genetic variants acting along with different environmental factors as in common epilepsies. Genetic testing and precision treatment have been developed for a few rare epilepsies and is lacking for common epilepsies due to their complex nature of inheritance. Precision medicine for common epilepsies require a panoramic approach that incorporates polygenic background and other non-genetic factors like microbiome, diet, age at disease onset, optimal time for treatment and other lifestyle factors which influence seizure threshold. This review aims to comprehensively present a state-of-art review of all the genes and their genetic variants that are associated with all common epilepsy subtypes. It also encompasses the basis of these genes in the epileptogenesis. Here, we discussed the current status of the common epilepsy genetics and address the clinical application so far on evidence-based markers in prognosis, diagnosis, and treatment management. In addition, we assessed the diagnostic predictability of a few genetic markers used for disease risk prediction in individuals. A combination of deeper endo-phenotyping including pharmaco-response data, electro-clinical imaging, and other clinical measurements along with genetics may be used to diagnose common epilepsies and this marks a step ahead in precision medicine in common epilepsies management.
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Stödberg T, Tomson T, Barbaro M, Stranneheim H, Anderlid BM, Carlsson S, Åmark P, Wedell A. Epilepsy syndromes, etiologies, and the use of next-generation sequencing in epilepsy presenting in the first 2 years of life: A population-based study. Epilepsia 2020; 61:2486-2499. [PMID: 32964447 PMCID: PMC7756847 DOI: 10.1111/epi.16701] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/28/2020] [Accepted: 08/31/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Population-based data on epilepsy syndromes and etiologies in early onset epilepsy are scarce. The use of next-generation sequencing (NGS) has hitherto not been reported in this context. The aim of this study is to describe children with epilepsy onset before 2 years of age, and to explore to what degree whole exome and whole genome sequencing (WES/WGS) can help reveal a molecular genetic diagnosis. METHODS Children presenting with a first unprovoked epileptic seizure before age 2 years and registered in the Stockholm Incidence Registry of Epilepsy (SIRE) between September 1, 2001 and December 31, 2006, were retrieved and their medical records up to age 7 years reviewed. Children who met the epilepsy criteria were included in the study cohort. WES/WGS was offered in cases of suspected genetic etiology regardless of whether a structural or metabolic diagnosis had been established. RESULTS One hundred sixteen children were included, of which 88 had seizure onset during the first year of life and 28 during the second, corresponding to incidences of 139 and 42/100 000 person-years, respectively. An epilepsy syndrome could be diagnosed in 54% of cases, corresponding to a birth prevalence of 1/1100. Structural etiology was revealed in 34% of cases, a genetic cause in 20%, and altogether etiology was known in 65% of children. The highest diagnostic yield was seen in magnetic resonance imaging (MRI) with 65% revealing an etiology. WES/WGS was performed in 26/116 cases (22%), with a diagnostic yield of 58%. SIGNIFICANCE Epilepsy syndromes can be diagnosed and etiologies revealed in a majority of early onset cases. NGS can identify a molecular diagnosis in a substantial number of children, and should be included in the work-up, especially in cases of epileptic encephalopathy, cerebral malformation, or metabolic disease without molecular diagnosis. A genetic diagnosis is essential to genetic counselling, prenatal diagnostics, and precision therapy.
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Affiliation(s)
- Tommy Stödberg
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Pediatric Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Torbjörn Tomson
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Michela Barbaro
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Henrik Stranneheim
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Sofia Carlsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Per Åmark
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
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44
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Ablinger C, Geisler SM, Stanika RI, Klein CT, Obermair GJ. Neuronal α 2δ proteins and brain disorders. Pflugers Arch 2020; 472:845-863. [PMID: 32607809 PMCID: PMC7351808 DOI: 10.1007/s00424-020-02420-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 01/31/2023]
Abstract
α2δ proteins are membrane-anchored extracellular glycoproteins which are abundantly expressed in the brain and the peripheral nervous system. They serve as regulatory subunits of voltage-gated calcium channels and, particularly in nerve cells, regulate presynaptic and postsynaptic functions independently from their role as channel subunits. α2δ proteins are the targets of the widely prescribed anti-epileptic and anti-allodynic drugs gabapentin and pregabalin, particularly for the treatment of neuropathic pain conditions. Recently, the human genes (CACNA2D1-4) encoding for the four known α2δ proteins (isoforms α2δ-1 to α2δ-4) have been linked to a large variety of neurological and neuropsychiatric disorders including epilepsy, autism spectrum disorders, bipolar disorders, schizophrenia, and depressive disorders. Here, we provide an overview of the hitherto identified disease associations of all known α2δ genes, hypothesize on the pathophysiological mechanisms considering their known physiological roles, and discuss the most immanent future research questions. Elucidating their specific physiological and pathophysiological mechanisms may open the way for developing entirely novel therapeutic paradigms for treating brain disorders.
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Affiliation(s)
- Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Stefanie M Geisler
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Ruslan I Stanika
- Division Physiology, Karl Landsteiner University of Health Sciences, 3500, Krems, Austria
| | - Christian T Klein
- Department of Life Sciences, IMC University of Applied Sciences, 3500, Krems, Austria
| | - Gerald J Obermair
- Institute of Physiology, Medical University Innsbruck, 6020, Innsbruck, Austria.
- Division Physiology, Karl Landsteiner University of Health Sciences, 3500, Krems, Austria.
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45
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Tang S, Addis L, Smith A, Topp SD, Pendziwiat M, Mei D, Parker A, Agrawal S, Hughes E, Lascelles K, Williams RE, Fallon P, Robinson R, Cross HJ, Hedderly T, Eltze C, Kerr T, Desurkar A, Hussain N, Kinali M, Bagnasco I, Vassallo G, Whitehouse W, Goyal S, Absoud M, Møller RS, Helbig I, Weber YG, Marini C, Guerrini R, Simpson MA, Pal DK. Phenotypic and genetic spectrum of epilepsy with myoclonic atonic seizures. Epilepsia 2020; 61:995-1007. [PMID: 32469098 DOI: 10.1111/epi.16508] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 02/24/2020] [Accepted: 03/27/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVE We aimed to describe the extent of neurodevelopmental impairments and identify the genetic etiologies in a large cohort of patients with epilepsy with myoclonic atonic seizures (MAE). METHODS We deeply phenotyped MAE patients for epilepsy features, intellectual disability, autism spectrum disorder, and attention-deficit/hyperactivity disorder using standardized neuropsychological instruments. We performed exome analysis (whole exome sequencing) filtered on epilepsy and neuropsychiatric gene sets to identify genetic etiologies. RESULTS We analyzed 101 patients with MAE (70% male). The median age of seizure onset was 34 months (range = 6-72 months). The main seizure types were myoclonic atonic or atonic in 100%, generalized tonic-clonic in 72%, myoclonic in 69%, absence in 60%, and tonic seizures in 19% of patients. We observed intellectual disability in 62% of patients, with extremely low adaptive behavioral scores in 69%. In addition, 24% exhibited symptoms of autism and 37% exhibited attention-deficit/hyperactivity symptoms. We discovered pathogenic variants in 12 (14%) of 85 patients, including five previously published patients. These were pathogenic genetic variants in SYNGAP1 (n = 3), KIAA2022 (n = 2), and SLC6A1 (n = 2), as well as KCNA2, SCN2A, STX1B, KCNB1, and MECP2 (n = 1 each). We also identified three new candidate genes, ASH1L, CHD4, and SMARCA2 in one patient each. SIGNIFICANCE MAE is associated with significant neurodevelopmental impairment. MAE is genetically heterogeneous, and we identified a pathogenic genetic etiology in 14% of this cohort by exome analysis. These findings suggest that MAE is a manifestation of several etiologies rather than a discrete syndromic entity.
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Affiliation(s)
- Shan Tang
- Evelina London Children's Hospital, London, UK
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Laura Addis
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
- Eli Lilly and Company, Erl Wood, Surrey, UK
| | - Anna Smith
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Simon D Topp
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Manuela Pendziwiat
- Clinic for Neuropediatrics, Schleswig-Holstein University Clinics, Kiel, Germany
| | - Davide Mei
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | | | - Shakti Agrawal
- Birmingham Children's Hospital National Health Service Foundation Trust, Birmingham, UK
| | - Elaine Hughes
- Evelina London Children's Hospital, London, UK
- King's College Hospital, London, UK
| | | | | | - Penny Fallon
- St George's National Health Service Health Care Trust, London, UK
| | - Robert Robinson
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
| | - Helen J Cross
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
- Clinical Neurosciences, UCL - Institute of Child Health, London, UK
| | | | - Christin Eltze
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
| | - Tim Kerr
- St George's National Health Service Health Care Trust, London, UK
| | - Archana Desurkar
- Sheffield Children's National Health Service Foundation Trust, Sheffield, UK
| | - Nahin Hussain
- University Hospital of Leicester National Health Service Trust, Leicester, UK
| | - Maria Kinali
- Chelsea and Westminster Hospital National Health Service Foundation Trust, London, UK
| | - Irene Bagnasco
- Child Neurology and Psychiatry Unit, Martini Hospital, Turin, Italy
| | | | | | - Sushma Goyal
- Evelina London Children's Hospital, London, UK
- King's College Hospital, London, UK
| | | | | | - Ingo Helbig
- Clinic for Neuropediatrics, Schleswig-Holstein University Clinics, Kiel, Germany
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yvonne G Weber
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Carla Marini
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Renzo Guerrini
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Michael A Simpson
- Division of Genetics and Molecular Medicine, King's College London, London, UK
| | - Deb K Pal
- Evelina London Children's Hospital, London, UK
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
- King's College Hospital, London, UK
- Medical Research Council Centre for Neurodevelopmental Disorders, King's College London, London, UK
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Abstract
Epilepsy encompasses a group of heterogeneous brain diseases that affect more than 50 million people worldwide. Epilepsy may have discernible structural, infectious, metabolic, and immune etiologies; however, in most people with epilepsy, no obvious cause is identifiable. Based initially on family studies and later on advances in gene sequencing technologies and computational approaches, as well as the establishment of large collaborative initiatives, we now know that genetics plays a much greater role in epilepsy than was previously appreciated. Here, we review the progress in the field of epilepsy genetics and highlight molecular discoveries in the most important epilepsy groups, including those that have been long considered to have a nongenetic cause. We discuss where the field of epilepsy genetics is moving as it enters a new era in which the genetic architecture of common epilepsies is starting to be unraveled.
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Affiliation(s)
- Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria 3000, Australia.,Departments of Medicine and Neurology, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria 3050, Australia.,Department of Neurology, Alfred Health, Melbourne, Victoria 3000, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,Department of Medical Biology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria 3084, Australia;
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Abstract
Developmental and epileptic encephalopathies (DEEs) can be primarily attributed to genetic causes. The genetic landscape of DEEs has been largely shaped by the rise of high-throughput sequencing, which led to the discovery of new DEE-associated genes and helped identify de novo pathogenic variants. We discuss briefly the contribution of de novo variants to DEE and also focus on alternative inheritance models that contribute to DEE. First, autosomal recessive inheritance in outbred populations may have a larger contribution than previously appreciated, accounting for up to 13% of DEEs. A small subset of genes that typically harbor de novo variants have been associated with recessive inheritance, and often these individuals have more severe clinical presentations. Additionally, pathogenic variants in X-linked genes have been identified in both affected males and females, possibly due to a lack of X-chromosome inactivation skewing. Collectively, exome sequencing has resulted in a molecular diagnosis for many individuals with DEE, but this still leaves many cases unsolved. Multiple factors contribute to the missing etiology, including nonexonic variants, mosaicism, epigenetics, and oligogenic inheritance. Here, we focus on the first 2 factors. We discuss the promises and challenges of genome sequencing, which allows for a more comprehensive analysis of the genome, including interpretation of structural and noncoding variants and also yields a high number of de novo variants for interpretation. We also consider the contribution of genetic mosaicism, both what it means for a molecular diagnosis in mosaic individuals and the important implications for genetic counseling.
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Affiliation(s)
- Hannah C Happ
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Gemma L Carvill
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Abstract
Developmental and epileptic encephalopathies (DEEs) are a group of severe, early onset epilepsies characterized by refractory seizures, developmental delay or regression associated with ongoing epileptic activity, and generally poor prognosis. DEE is genetically and phenotypically heterogeneous, and there is a plethora of genetic testing options to investigate the rapidly growing list of epilepsy genes. However, more than 50% of patients with DEE remain without a genetic diagnosis despite state-of-the-art genetic testing. In this review, we discuss the major advances in epilepsy genomics that have surfaced in recent years. The goal of this review is to reach a larger audience and build a better understanding of pathogenesis and genetic testing options in DEE.
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Affiliation(s)
- Malavika Hebbar
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, 98105, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, 98105, USA
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49
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Symonds JD, McTague A. Epilepsy and developmental disorders: Next generation sequencing in the clinic. Eur J Paediatr Neurol 2020; 24:15-23. [PMID: 31882278 DOI: 10.1016/j.ejpn.2019.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND The advent of Next Generation Sequencing (NGS) has led to a redefining of the genetic landscape of the epilepsies. Hundreds of single gene epilepsies have been described. Genes associated with epilepsy involve diverse processes. Now a substantial proportion of individuals with epilepsy can receive a high definition molecular genetic diagnosis. METHODS In this review we update the current genetic landscape of the epilepsies and categorise the major functional groupings of epilepsy-associated genes. We describe currently available genetic testing approaches. We perform a literature review of NGS studies and review the factors which determine yield in cohorts undergoing testing. We identify factors associated with positive genetic diagnosis and consider the utility of genetic testing in terms of treatment selection as well as more qualitative aspects of care. FINDINGS Epilepsy-associated genes can be grouped into five broad functional categories: ion transport; cell growth and differentiation; regulation of synaptic processes; transport and metabolism of small molecules within and between cells; and regulation of gene transcription and translation. Early onset of seizures, drug-resistance, and developmental comorbidity are associated with higher diagnostic yield. The most commonly implicated genes in NGS studies to date, in order, are SCN1A, KCNQ2, CDKL5, SCN2A, and STXBP1. In unselected infantile cohorts PRRT2, a gene associated with self-limited epilepsy, is frequently implicated. Genetic diagnosis provides utility in terms of treatment choice closing the diagnostic odyssey, avoiding unnecessary further testing, and informing future reproductive decisions. CONCLUSIONS Genetic testing has become a first line test in epilepsy. As techniques improve and understanding advances, its utility is set to increase. Genetic diagnosis, particularly in early onset developmental and epileptic encephalopathies, influences treatment choice in a significant proportion of patients. The realistic prospect of gene therapy is a cause for optimism.
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Affiliation(s)
- Joseph D Symonds
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow, G51 4TF, UK; Medical Veterinary and Life Sciences, University of Glasgow, G12 8QQ, UK.
| | - Amy McTague
- Institute of Child Health, University Collge London, 30 Guilford St, Holborn, London WC1N 1EH, UK
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50
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Duy PQ, David WB, Kahle KT. Identification of KCC2 Mutations in Human Epilepsy Suggests Strategies for Therapeutic Transporter Modulation. Front Cell Neurosci 2019; 13:515. [PMID: 31803025 PMCID: PMC6873151 DOI: 10.3389/fncel.2019.00515] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/01/2019] [Indexed: 11/28/2022] Open
Abstract
Epilepsy is a common neurological disorder characterized by recurrent and unprovoked seizures thought to arise from impaired balance between neuronal excitation and inhibition. Our understanding of the neurophysiological mechanisms that render the brain epileptogenic remains incomplete, reflected by the lack of satisfactory treatments that can effectively prevent epileptic seizures without significant drug-related adverse effects. Type 2 K+-Cl− cotransporter (KCC2), encoded by SLC12A5, is important for chloride homeostasis and neuronal excitability. KCC2 dysfunction attenuates Cl− extrusion and impairs GABAergic inhibition, and can lead to neuronal hyperexcitability. Converging lines of evidence from human genetics have secured the link between KCC2 dysfunction and the development of epilepsy. Here, we review KCC2 mutations in human epilepsy and discuss potential therapeutic strategies based on the functional impact of these mutations. We suggest that a strategy of augmenting KCC2 activity by antagonizing its critical inhibitory phosphorylation sites may be a particularly efficacious method of facilitating Cl− extrusion and restoring GABA inhibition to treat medication-refractory epilepsy and other seizure disorders.
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Affiliation(s)
- Phan Q Duy
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, United States.,Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT, United States
| | - Wyatt B David
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, United States
| | - Kristopher T Kahle
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, United States.,Department of Genetics, Yale University School of Medicine, New Haven, CT, United States.,Departments of Pediatrics and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, United States.,Yale-Rockefeller NIH Centers for Mendelian Genomics, Yale University, New Haven, CT, United States.,Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, United States
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