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Heebner M, Mainali G, Wei S, Kumar A, Naik S, Pradhan S, Kandel P, Tencer J, Carney P, Paudel S. Importance of Genetic Testing in Children With Generalized Epilepsy. Cureus 2024; 16:e59991. [PMID: 38854234 PMCID: PMC11162283 DOI: 10.7759/cureus.59991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2024] [Indexed: 06/11/2024] Open
Abstract
INTRODUCTION Epilepsy is a neurological disorder characterized by the predisposition for recurrent unprovoked seizures. It can broadly be classified as focal, generalized, unclassified, and unknown in its onset. Focal epilepsy originates in and involves networks localized to one region of the brain. Generalized epilepsy engages broader, more diffuse networks. The etiology of epilepsy can be structural, genetic, infectious, metabolic, immune, or unknown. Many generalized epilepsies have presumed genetic etiologies. The aim of this study is to compare the role of genetic testing to brain MRI as diagnostic tools for identifying the underlying causes of idiopathic (genetic) generalized epilepsy (IGE). METHODS We evaluated the diagnostic yield of these two categories in children diagnosed with IGE. Data collection was completed using ICD10 codes filtered by TriNetX to select 982 individual electronic medical records (EMRs) of children in the Penn State Children's Hospital who received a diagnosis of IGE. The diagnosis was confirmed after reviewing the clinical history and electroencephalogram (EEG) data for each patient. RESULTS From this dataset, neuroimaging and genetic testing results were gathered. A retrospective chart review was done on 982 children with epilepsy, of which 143 (14.5%) met the criteria for IGE. Only 18 patients underwent genetic testing. Abnormalities that could be a potential cause for epilepsy were seen in 72.2% (13/18) of patients with IGE and abnormal genetic testing, compared to 30% (37/123) for patients who had a brain MRI with genetic testing. CONCLUSION This study suggests that genetic testing may be more useful than neuroimaging for identifying an etiological diagnosis of pediatric patients with IGE.
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Affiliation(s)
| | - Gayatra Mainali
- Pediatric Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, USA
| | - Sharon Wei
- Neurology, Penn State University, Hershey, USA
| | - Ashutosh Kumar
- Pediatric Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, USA
| | - Sunil Naik
- Pediatric Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, USA
| | | | - Prakash Kandel
- Biostatistics, Penn State College of Medicine, Hershey, USA
| | - Jaclyn Tencer
- Pediatric Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, USA
| | - Paul Carney
- Pediatrics and Neurology, University of Missouri, Columbia, USA
| | - Sita Paudel
- Pediatric Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, USA
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Lin ZJ, He JW, Zhu SY, Xue LH, Zheng JF, Zheng LQ, Huang BX, Chen GZ, Lin PX. Gene-gene interaction network analysis indicates CNTN2 is a candidate gene for idiopathic generalized epilepsy. Neurogenetics 2024; 25:131-139. [PMID: 38460076 DOI: 10.1007/s10048-024-00748-w] [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: 11/16/2023] [Accepted: 01/19/2024] [Indexed: 03/11/2024]
Abstract
Twin and family studies have established the genetic contribution to idiopathic generalized epilepsy (IGE). The genetic architecture of IGE is generally complex and heterogeneous, and the majority of the genetic burden in IGE remains unsolved. We hypothesize that gene-gene interactions contribute to the complex inheritance of IGE. CNTN2 (OMIM* 615,400) variants have been identified in cases with familial adult myoclonic epilepsy and other epilepsies. To explore the gene-gene interaction network in IGE, we took the CNTN2 gene as an example and investigated its co-occurrent genetic variants in IGE cases. We performed whole-exome sequencing in 114 unrelated IGE cases and 296 healthy controls. Variants were qualified with sequencing quality, minor allele frequency, in silico prediction, genetic phenotype, and recurrent case numbers. The STRING_TOP25 gene interaction network analysis was introduced with the bait gene CNTN2 (denoted as A). The gene-gene interaction pair mode was presumed to be A + c, A + d, A + e, with a leading gene A, or A + B + f, A + B + g, A + B + h, with a double-gene A + B, or other combinations. We compared the number of gene interaction pairs between the case and control groups. We identified three pairs in the case group, CNTN2 + PTPN18, CNTN2 + CNTN1 + ANK2 + ANK3 + SNTG2, and CNTN2 + PTPRZ1, while we did not discover any pairs in the control group. The number of gene interaction pairs in the case group was much more than in the control group (p = 0.021). Taking together the genetic bioinformatics, reported epilepsy cases, and statistical evidence in the study, we supposed CNTN2 as a candidate pathogenic gene for IGE. The gene interaction network analysis might help screen candidate genes for IGE or other complex genetic disorders.
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Affiliation(s)
- Zhi-Jian Lin
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Jun-Wei He
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Sheng-Yin Zhu
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Li-Hong Xue
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Jian-Feng Zheng
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Li-Qin Zheng
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Bi-Xia Huang
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Guo-Zhang Chen
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China
| | - Peng-Xing Lin
- Department of Neurology, School of Clinical Medicine, the Affiliated Hospital of Putian UniversityFujian Medical UniversityBrain Science Institute of Putian University, 999 Dongzhen East Road, Licheng District, Putian, 351100, China.
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3
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Zhang L, Wang Y. Gene therapy in epilepsy. Biomed Pharmacother 2021; 143:112075. [PMID: 34488082 DOI: 10.1016/j.biopha.2021.112075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 01/15/2023] Open
Abstract
Gene therapy may constitute a promising alternative to conventional pharmacological tools and surgeries for epilepsy. For primary epilepsy, a single variant leading to a significant effect is relatively rare, while other forms are considered complex in inheritances with multiple susceptible mutations and impacts from the environment. Gene therapy in preclinical models of epilepsy has attempted to perform antiepileptogenic, anticonvulsant, or disease-modifying effects during epileptogenesis or after establishing the disease. Creating gene vectors tailored for different situations is the key to expanding gene therapy, and choosing the appropriate therapeutic target remains another fundamental problem. A variety of treatment strategies, from overexpressing inhibitory neuropeptides to modulating the expression of neurotransmitters or ion channels, have been tested in animal models. Additionally, emerging new approaches of optogenetics and chemogenetics, as well as genome-editing tools will further boost the prosperity of gene therapy. This review summarizes the experience obtained to date and discusses the challenges and opportunities in clinical translations.
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Affiliation(s)
- Lu Zhang
- Department of Neurology at Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Yuping Wang
- Beijing Key Laboratory of Neuromodulation, Capital Medical University, Beijing, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.
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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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Gamirova RG, Gamirova RR, Esin RG. [Genetics of epilepsy: successes, problems and development prospects]. Zh Nevrol Psikhiatr Im S S Korsakova 2020; 120:144-150. [PMID: 33081460 DOI: 10.17116/jnevro2020120091144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The authors present a detailed review of current advances in the field of genetics of epilepsy. Separately, new views on the etiology and pathogenesis of genetic epileptic encephalopathies, focal epilepsy and idiopathic generalized epilepsies are examined. The authors emphasize the importance of genetic discoveries for the clinical practice, including the prospects in the development of patients' personalized treatment. A comparative analysis of the value of various methods of genetic research in the diagnosis of epilepsy, methods of integrating molecular genetic analyses into everyday practical medicine is presented.
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Affiliation(s)
- R G Gamirova
- Kazan State Medical Academy - branch of Russian Medical Academy of Continuing Professional Education, Kazan, Russia.,Kazan (Volga Region) Federal University, Kazan, Russia
| | - R R Gamirova
- Kazan (Volga Region) Federal University, Kazan, Russia
| | - R G Esin
- Kazan State Medical Academy - branch of Russian Medical Academy of Continuing Professional Education, Kazan, Russia.,Kazan (Volga Region) Federal University, Kazan, Russia
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Gesche J, Hjalgrim H, Rubboli G, Beier CP. The clinical spectrum of familial and sporadic idiopathic generalized epilepsy. Epilepsy Res 2020; 165:106374. [DOI: 10.1016/j.eplepsyres.2020.106374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 05/11/2020] [Accepted: 05/22/2020] [Indexed: 12/31/2022]
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Abstract
PURPOSE OF REVIEW Seizures can arise in neocortical, thalamocortical, limbic or brainstem networks. Here, we review recent genetic mechanisms implicated in focal and genetic generalized epilepsies (GGEs). RECENT FINDINGS Pathogenic variation in GAP activity toward RAGs 1 (GATOR1) complex genes (i.e., DEPDC5, NPRL2 and NPRL3) mainly result in focal epilepsies. They are associated with high rates of sudden unexpected death in epilepsy and malformations of cortical development (MCD), where "two-hits" in GATOR1-related pathways are also found in MCDs. Large-scale sequencing studies continue to reveal new genetic risk (germline or somatic) variants, and new genes relevant to epileptic encephalopathies (EEs). Genes previously associated with EEs, including GABAA receptor genes, are now known to play a role in both common focal and GGEs in individuals without intellectual disabilities. These findings suggest that there may be a common pathophysiological mechanism in GGEs and focal epilepsies. Finally, polygenic risk scores, based on common genetic variation, offer promise in helping to differentiate between GGEs and common forms of focal epilepsies. Genetic abnormalities are a significant cause of common sporadic epilepsies, epilepsies associated with inflammatory markers, and focal epilepsies with or without MCD. Future studies using genome sequencing may provide more answers to the remaining unresolved epilepsy cases.
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McCarthy E, Shakil F, Saint Ange P, Morris Cameron E, Miller J, Pathak S, Greenberg DA, Velíšková J, Velíšek L. Developmental decrease in parvalbumin-positive neurons precedes increase in flurothyl-induced seizure susceptibility in the Brd2 +/- mouse model of juvenile myoclonic epilepsy. Epilepsia 2020; 61:892-902. [PMID: 32301507 DOI: 10.1111/epi.16499] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/02/2020] [Accepted: 03/18/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVE BRD2 is a human gene repeatedly linked to and associated with juvenile myoclonic epilepsy (JME). Here, we define the developmental stage when increased seizure susceptibility first manifests in heterozygous Brd2+/- mice, an animal model of JME. We wanted to determine (1) whether seizure susceptibility correlates with the proven decrease of γ-aminobutyric acidergic (GABAergic) neuron numbers and (2) whether the seizure phenotype can be affected by sex hormones. METHODS Heterozygous (Brd2+/-) and wild-type (wt) mice of both sexes were tested for flurothyl-induced seizure susceptibility at postnatal day 15 (P15; wt, n = 13; Brd2+/-, n = 20), at P30 (wt, n = 20; Brd2+/-, n = 20), and in adulthood (5-6 months of age; wt, n = 10; Brd2+/-, n = 12). We measured latency to clonic and tonic-clonic seizure onset (flurothyl threshold). We also compared relative density of parvalbumin-positive (PVA+) and GAD67+ GABA neurons in the striatum and primary motor (M1) neocortex of P15 (n = 6-13 mice per subgroup) and P30 (n = 7-10 mice per subgroup) mice. Additional neonatal Brd2+/- mice were injected with testosterone propionate (females) or formestane (males) and challenged with flurothyl at P30. RESULTS P15 Brd2+/- mice showed no difference in seizure susceptibility compared to P15 wt mice. However, even at this early age, Brd2+/- mice showed fewer PVA+ neurons in the striatum and M1 neocortex. Compared to wt, the striatum in Brd2+/- mice showed an increased proportion of immature PVA+ neurons, with smaller cell bodies and limited dendritic arborization. P30 Brd2+/- mice displayed increased susceptibility to flurothyl-induced clonic seizures compared to wt. Both genotype and sex strongly influenced the density of PVA+ neurons in the striatum. Susceptibility to clonic seizures remained increased in adult Brd2+/- mice, and additionally there was increased susceptibility to tonic-clonic seizures. In P30 females, neonatal testosterone reduced the number of flurothyl-induced clonic seizures. SIGNIFICANCE A decrease in striatal PVA+ GABAergic neurons developmentally precedes the onset of increased seizure susceptibility and likely contributes to the expression of the syndrome.
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Affiliation(s)
- Emily McCarthy
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Faariah Shakil
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Patrick Saint Ange
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Emily Morris Cameron
- Department of Pediatrics, Wexner Medical Center, Ohio State University and Battelle Center for Mathematical Medicine, Nationwide Children's Hospital, Columbus, Ohio
| | - James Miller
- Department of Pediatrics, Wexner Medical Center, Ohio State University and Battelle Center for Mathematical Medicine, Nationwide Children's Hospital, Columbus, Ohio
| | - Shilpa Pathak
- Department of Pediatrics, Wexner Medical Center, Ohio State University and Battelle Center for Mathematical Medicine, Nationwide Children's Hospital, Columbus, Ohio
| | - David A Greenberg
- Department of Pediatrics, Wexner Medical Center, Ohio State University and Battelle Center for Mathematical Medicine, Nationwide Children's Hospital, Columbus, Ohio
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Obstetrics & Gynecology, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York.,Department of Pediatrics, New York Medical College, Valhalla, New York
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Whole exome sequencing identifies a novel SCN1A mutation in genetic (idiopathic) generalized epilepsy and juvenile myoclonic epilepsy subtypes. Neurol Sci 2019; 41:591-598. [DOI: 10.1007/s10072-019-04122-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/22/2019] [Indexed: 12/30/2022]
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10
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van Eyk CL, Corbett MA, Frank MSB, Webber DL, Newman M, Berry JG, Harper K, Haines BP, McMichael G, Woenig JA, MacLennan AH, Gecz J. Targeted resequencing identifies genes with recurrent variation in cerebral palsy. NPJ Genom Med 2019; 4:27. [PMID: 31700678 PMCID: PMC6828700 DOI: 10.1038/s41525-019-0101-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/17/2019] [Indexed: 01/13/2023] Open
Abstract
A growing body of evidence points to a considerable and heterogeneous genetic aetiology of cerebral palsy (CP). To identify recurrently variant CP genes, we designed a custom gene panel of 112 candidate genes. We tested 366 clinically unselected singleton cases with CP, including 271 cases not previously examined using next-generation sequencing technologies. Overall, 5.2% of the naïve cases (14/271) harboured a genetic variant of clinical significance in a known disease gene, with a further 4.8% of individuals (13/271) having a variant in a candidate gene classified as intolerant to variation. In the aggregate cohort of individuals from this study and our previous genomic investigations, six recurrently hit genes contributed at least 4% of disease burden to CP: COL4A1, TUBA1A, AGAP1, L1CAM, MAOB and KIF1A. Significance of Rare VAriants (SORVA) burden analysis identified four genes with a genome-wide significant burden of variants, AGAP1, ERLIN1, ZDHHC9 and PROC, of which we functionally assessed AGAP1 using a zebrafish model. Our investigations reinforce that CP is a heterogeneous neurodevelopmental disorder with known as well as novel genetic determinants.
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Affiliation(s)
- C L van Eyk
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - M A Corbett
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - M S B Frank
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - D L Webber
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - M Newman
- 3Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA Australia
| | - J G Berry
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - K Harper
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - B P Haines
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - G McMichael
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - J A Woenig
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - A H MacLennan
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia
| | - J Gecz
- 1Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,2Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA Australia.,4South Australian Health and Medical Research Institute, Adelaide, SA Australia
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Khalyfa A, Sanz-Rubio D. Genetics and Extracellular Vesicles of Pediatrics Sleep Disordered Breathing and Epilepsy. Int J Mol Sci 2019; 20:ijms20215483. [PMID: 31689970 PMCID: PMC6862182 DOI: 10.3390/ijms20215483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/14/2019] [Accepted: 10/28/2019] [Indexed: 12/27/2022] Open
Abstract
Sleep remains one of the least understood phenomena in biology, and sleep disturbances are one of the most common behavioral problems in childhood. The etiology of sleep disorders is complex and involves both genetic and environmental factors. Epilepsy is the most popular childhood neurological condition and is characterized by an enduring predisposition to generate epileptic seizures, and the neurobiological, cognitive, psychological, and social consequences of this condition. Sleep and epilepsy are interrelated, and the importance of sleep in epilepsy is less known. The state of sleep also influences whether a seizure will occur at a given time, and this differs considerably for various epilepsy syndromes. The development of epilepsy has been associated with single or multiple gene variants. The genetics of epilepsy is complex and disorders exhibit significant genetic heterogeneity and variability in the expressivity of seizures. Phenobarbital (PhB) is the most widely used antiepileptic drug. With its principal mechanism of action to prolong the opening time of the γ-aminobutyric acid (GABA)-A receptor-associated chloride channel, it enhances chloride anion influx into neurons, with subsequent hyperpolarization, thereby reducing excitability. Enzymes that metabolize pharmaceuticals including PhB are well known for having genetic polymorphisms that contribute to adverse drug–drug interactions. PhB metabolism is highly dependent upon the cytochrome P450 (CYP450) and genetic polymorphisms can lead to variability in active drug levels. The highly polymorphic CYP2C19 isozymes are responsible for metabolizing a large portion of routinely prescribed drugs and variants contribute significantly to adverse drug reactions and therapeutic failures. A limited number of CYP2C19 single nucleotide polymorphisms (SNPs) are involved in drug metabolism. Extracellular vesicles (EVs) are circular membrane fragments released from the endosomal compartment as exosomes are shed from the surfaces of the membranes of most cell types. Increasing evidence indicated that EVs play a pivotal role in cell-to-cell communication. Theses EVs may play an important role between sleep, epilepsy, and treatments. The discovery of exosomes provides potential strategies for the diagnosis and treatment of many diseases including neurocognitive deficit. The aim of this study is to better understand and provide further knowledge about the metabolism and interactions between phenobarbital and CYP2C19 polymorphisms in children with epilepsy, interplay between sleep, and EVs. Understanding this interplay between epilepsy and sleep is helpful in the optimal treatment of all patients with epileptic seizures. The use of genetics and extracellular vesicles as precision medicine for the diagnosis and treatment of children with sleep disorder will improve the prognosis and the quality of life in patients with epilepsy.
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Affiliation(s)
- Abdelnaby Khalyfa
- Department of Pediatrics, Section of Sleep Medicine, The University of Chicago, Chicago, IL 60637, USA.
- Department of Child Health and the Child Health Research Institute, University of Missouri School of Medicine, Columbia, MO 65201, USA.
| | - David Sanz-Rubio
- Department of Child Health and the Child Health Research Institute, University of Missouri School of Medicine, Columbia, MO 65201, USA.
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Krenn M, Ernst M, Tomschik M, Treven M, Wagner M, Westphal DS, Meitinger T, Pataraia E, Zimprich F, Aull-Watschinger S. Phenotypic variability of GABRA1-related epilepsy in monozygotic twins. Ann Clin Transl Neurol 2019; 6:2317-2322. [PMID: 31568673 PMCID: PMC6856628 DOI: 10.1002/acn3.50895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 01/01/2023] Open
Abstract
Variants in GABRA1 have been associated with different epilepsies ranging from mild generalized forms to epileptic encephalopathies. Despite the broad clinical spectrum, phenotypes were found to be largely concordant within families. Contrary to this observation, we report monozygotic twin sisters with generalized epilepsy due to the c.541C>T; p.(Pro181Ser) de novo variant in GABRA1. One experienced juvenile absence seizures promptly responding to first-line medication, whereas the second developed severe treatment-refractory epilepsy with febrile, absence, atonic, and tonic-clonic seizures indicating marked intrafamilial variability in GABRA1-related epilepsy. Moreover, we provide a molecular characterization of the novel variant based on recently published structural data.
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Affiliation(s)
- Martin Krenn
- Department of Neurology, Medical University of Vienna, Vienna, Austria.,Institute of Human Genetics, Technical University Munich, Munich, Germany
| | - Margot Ernst
- Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Matthias Tomschik
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Marco Treven
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Matias Wagner
- Institute of Human Genetics, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Dominik S Westphal
- Institute of Human Genetics, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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Gilsoul M, Grisar T, Delgado-Escueta AV, de Nijs L, Lakaye B. Subtle Brain Developmental Abnormalities in the Pathogenesis of Juvenile Myoclonic Epilepsy. Front Cell Neurosci 2019; 13:433. [PMID: 31611775 PMCID: PMC6776584 DOI: 10.3389/fncel.2019.00433] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME), a lifelong disorder that starts during adolescence, is the most common of genetic generalized epilepsy syndromes. JME is characterized by awakening myoclonic jerks and myoclonic-tonic-clonic (m-t-c) grand mal convulsions. Unfortunately, one third of JME patients have drug refractory m-t-c convulsions and these recur in 70-80% who attempt to stop antiepileptic drugs (AEDs). Behavioral studies documented impulsivity, but also impairment of executive functions relying on organization and feedback, which points to prefrontal lobe dysfunction. Quantitative voxel-based morphometry (VBM) revealed abnormalities of gray matter (GM) volumes in cortical (frontal and parietal) and subcortical structures (thalamus, putamen, and hippocampus). Proton magnetic resonance spectroscopy (MRS) found evidence of dysfunction of thalamic neurons. White matter (WM) integrity was disrupted in corpus callosum and frontal WM tracts. Magnetic resonance imaging (MRI) further unveiled anomalies in both GM and WM structures that were already present at the time of seizure onset. Aberrant growth trajectories of brain development occurred during the first 2 years of JME diagnosis. Because of genetic origin, disease causing variants were sought, first by positional cloning, and most recently, by next generation sequencing. To date, only six genes harboring pathogenic variants (GABRA1, GABRD, EFHC1, BRD2, CASR, and ICK) with Mendelian and complex inheritance and covering a limited proportion of the world population, are considered as major susceptibility alleles for JME. Evidence on the cellular role, developmental and cell-type expression profiles of these six diverse JME genes, point to their pathogenic variants driving the first steps of brain development when cell division, expansion, axial, and tangential migration of progenitor cells (including interneuron cortical progenitors) sculpture subtle alterations in brain networks and microcircuits during development. These alterations may explain "microdysgenesis" neuropathology, impulsivity, executive dysfunctions, EEG polyspike waves, and awakening m-t-c convulsions observed in JME patients.
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Affiliation(s)
- Maxime Gilsoul
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Thierry Grisar
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Antonio V. Delgado-Escueta
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Laurence de Nijs
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands
| | - Bernard Lakaye
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Feng YCA, Howrigan DP, Abbott LE, Tashman K, Cerrato F, Singh T, Heyne H, Byrnes A, Churchhouse C, Watts N, Solomonson M, Lal D, Heinzen EL, Dhindsa RS, Stanley KE, Cavalleri GL, Hakonarson H, Helbig I, Krause R, May P, Weckhuysen S, Petrovski S, Kamalakaran S, Sisodiya SM, Cossette P, Cotsapas C, De Jonghe P, Dixon-Salazar T, Guerrini R, Kwan P, Marson AG, Stewart R, Depondt C, Dlugos DJ, Scheffer IE, Striano P, Freyer C, McKenna K, Regan BM, Bellows ST, Leu C, Bennett CA, Johns EM, Macdonald A, Shilling H, Burgess R, Weckhuysen D, Bahlo M, O’Brien TJ, Todaro M, Stamberger H, Andrade DM, Sadoway TR, Mo K, Krestel H, Gallati S, Papacostas SS, Kousiappa I, Tanteles GA, Štěrbová K, Vlčková M, Sedláčková L, Laššuthová P, Klein KM, Rosenow F, Reif PS, Knake S, Kunz WS, Zsurka G, Elger CE, Bauer J, Rademacher M, Pendziwiat M, Muhle H, Rademacher A, van Baalen A, von Spiczak S, Stephani U, Afawi Z, Korczyn AD, Kanaan M, Canavati C, Kurlemann G, Müller-Schlüter K, Kluger G, Häusler M, Blatt I, Lemke JR, Krey I, Weber YG, Wolking S, Becker F, Hengsbach C, Rau S, Maisch AF, Steinhoff BJ, Schulze-Bonhage A, Schubert-Bast S, Schreiber H, Borggräfe I, Schankin CJ, Mayer T, Korinthenberg R, Brockmann K, Kurlemann G, Dennig D, Madeleyn R, Kälviäinen R, Auvinen P, Saarela A, Linnankivi T, Lehesjoki AE, Rees MI, Chung SK, Pickrell WO, Powell R, Schneider N, Balestrini S, Zagaglia S, Braatz V, Johnson MR, Auce P, Sills GJ, Baum LW, Sham PC, Cherny SS, Lui CH, Barišić N, Delanty N, Doherty CP, Shukralla A, McCormack M, El-Naggar H, Canafoglia L, Franceschetti S, Castellotti B, Granata T, Zara F, Iacomino M, Madia F, Vari MS, Mancardi MM, Salpietro V, Bisulli F, Tinuper P, Licchetta L, Pippucci T, Stipa C, Minardi R, Gambardella A, Labate A, Annesi G, Manna L, Gagliardi M, Parrini E, Mei D, Vetro A, Bianchini C, Montomoli M, Doccini V, Marini C, Suzuki T, Inoue Y, Yamakawa K, Tumiene B, Sadleir LG, King C, Mountier E, Caglayan SH, Arslan M, Yapıcı Z, Yis U, Topaloglu P, Kara B, Turkdogan D, Gundogdu-Eken A, Bebek N, Uğur-İşeri S, Baykan B, Salman B, Haryanyan G, Yücesan E, Kesim Y, Özkara Ç, Poduri A, Shiedley BR, Shain C, Buono RJ, Ferraro TN, Sperling MR, Lo W, Privitera M, French JA, Schachter S, Kuzniecky RI, Devinsky O, Hegde M, Khankhanian P, Helbig KL, Ellis CA, Spalletta G, Piras F, Piras F, Gili T, Ciullo V, Reif A, McQuillin A, Bass N, McIntosh A, Blackwood D, Johnstone M, Palotie A, Pato MT, Pato CN, Bromet EJ, Carvalho CB, Achtyes ED, Azevedo MH, Kotov R, Lehrer DS, Malaspina D, Marder SR, Medeiros H, Morley CP, Perkins DO, Sobell JL, Buckley PF, Macciardi F, Rapaport MH, Knowles JA, Fanous AH, McCarroll SA, Gupta N, Gabriel SB, Daly MJ, Lander ES, Lowenstein DH, Goldstein DB, Lerche H, Berkovic SF, Neale BM. Ultra-Rare Genetic Variation in the Epilepsies: A Whole-Exome Sequencing Study of 17,606 Individuals. Am J Hum Genet 2019; 105:267-282. [PMID: 31327507 PMCID: PMC6698801 DOI: 10.1016/j.ajhg.2019.05.020] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/29/2019] [Indexed: 12/20/2022] Open
Abstract
Sequencing-based studies have identified novel risk genes associated with severe epilepsies and revealed an excess of rare deleterious variation in less-severe forms of epilepsy. To identify the shared and distinct ultra-rare genetic risk factors for different types of epilepsies, we performed a whole-exome sequencing (WES) analysis of 9,170 epilepsy-affected individuals and 8,436 controls of European ancestry. We focused on three phenotypic groups: severe developmental and epileptic encephalopathies (DEEs), genetic generalized epilepsy (GGE), and non-acquired focal epilepsy (NAFE). We observed that compared to controls, individuals with any type of epilepsy carried an excess of ultra-rare, deleterious variants in constrained genes and in genes previously associated with epilepsy; we saw the strongest enrichment in individuals with DEEs and the least strong in individuals with NAFE. Moreover, we found that inhibitory GABAA receptor genes were enriched for missense variants across all three classes of epilepsy, whereas no enrichment was seen in excitatory receptor genes. The larger gene groups for the GABAergic pathway or cation channels also showed a significant mutational burden in DEEs and GGE. Although no single gene surpassed exome-wide significance among individuals with GGE or NAFE, highly constrained genes and genes encoding ion channels were among the lead associations; such genes included CACNA1G, EEF1A2, and GABRG2 for GGE and LGI1, TRIM3, and GABRG2 for NAFE. Our study, the largest epilepsy WES study to date, confirms a convergence in the genetics of severe and less-severe epilepsies associated with ultra-rare coding variation, and it highlights a ubiquitous role for GABAergic inhibition in epilepsy etiology.
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Wang M, Greenberg DA, Stewart WCL. Replication, reanalysis, and gene expression: ME2 and genetic generalized epilepsy. Epilepsia 2019; 60:539-546. [PMID: 30719716 DOI: 10.1111/epi.14654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 12/28/2018] [Accepted: 01/04/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Genetic generalized epilepsy (GGE) consists of epileptic syndromes with overlapping symptoms and is considered to be largely genetic. Previous cosegregation and association studies have pointed to malic enzyme 2 (ME2) as a candidate susceptibility gene for adolescent-onset GGE. In this article, we present new evidence supporting ME2's involvement in GGE. METHODS To definitively test ME2's influence on GGE, we used 3 different approaches. First, we compared a newly recruited GGE cohort with an ethnically matched reference sample from 1000 Genomes Project, using an efficient test of association (POPFAM+). Second, we used POPFAM+ to reanalyze a previously collected data set, wherein the original controls were replaced with ethnically matched reference samples to minimize the confounding effect of population stratification. Third, in a post hoc analysis of expression data from healthy human prefrontal cortex, we identified single nucleotide polymorphisms (SNPs) influencing ME2 messenger RNA (mRNA) expression; and then we tested those same SNPs for association with GGE in a large case-control cohort. RESULTS First, in the analysis of our newly recruited GGE Cohort, we found a strong association between an ME2 SNP and GGE (P = 0.0006 at rs608781). Second, in the reanalysis of previously collected data, we confirmed the Greenberg et al (2005) finding of a GGE-associated ME2 risk haplotype. Third, in the post hoc ME2 expression analysis, we found evidence for a possible link between GGE and ME2 gene expression in human brain. SIGNIFICANCE Overall, our research, and the research of others, provides compelling evidence that ME2 influences susceptibility to adolescent-onset GGE.
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Affiliation(s)
- Meng Wang
- The Research Institute at Nationwide Children's Hospital, Nationwide Children's Hospital, Columbus, Ohio
| | | | - William C L Stewart
- The Research Institute at Nationwide Children's Hospital, Nationwide Children's Hospital, Columbus, Ohio.,Department of Statistics, The Ohio State University, Columbus, Ohio.,Department of Pediatrics, The Ohio State University, Columbus, Ohio
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Genomics in neurodevelopmental disorders: an avenue to personalized medicine. Exp Mol Med 2018; 50:1-7. [PMID: 30089840 PMCID: PMC6082867 DOI: 10.1038/s12276-018-0129-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/30/2018] [Accepted: 05/16/2018] [Indexed: 01/25/2023] Open
Abstract
Despite the remarkable number of scientific breakthroughs of the last 100 years, the treatment of neurodevelopmental disorders (e.g., autism spectrum disorder, intellectual disability) remains a great challenge. Recent advancements in genomics, such as whole-exome or whole-genome sequencing, have enabled scientists to identify numerous mutations underlying neurodevelopmental disorders. Given the few hundred risk genes that have been discovered, the etiological variability and the heterogeneous clinical presentation, the need for genotype—along with phenotype-based diagnosis of individual patients has become a requisite. In this review we look at recent advancements in genomic analysis and their translation into clinical practice. The identification of genetic mutations associated with neurodevelopmental disorders (NDDs) along with routine diagnosis based on patients’ characteristics is aiding the delivery of personalized therapies. Dora Tarlungeanu and Gaia Novarino at the Institute of Science and Technology in Klosterneuburg, Austria, review recent advances in genetic technologies, such as whole exome sequencing, that can lead to early intervention, guide choice of treatment and prompt genetic counseling. Introducing the mutations associated with NDDs into model organisms or stem cells is revealing some of the mechanisms underlying NDDs and enabling the evaluation of novel therapeutic strategies that target core symptoms of the disorders. To accelerate the implementation of individualized treatments for NDD the authors highlight the need to adopt interdisciplinary research approaches and to keep clinical staff updated on the latest findings in NDD genetics.
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Rare coding variants in genes encoding GABA A receptors in genetic generalised epilepsies: an exome-based case-control study. Lancet Neurol 2018; 17:699-708. [PMID: 30033060 DOI: 10.1016/s1474-4422(18)30215-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 05/17/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We aimed to investigate the burden of rare genetic variants in genetic generalised epilepsy. METHODS For this exome-based case-control study, we used three different genetic generalised epilepsy case cohorts and three independent control cohorts, all of European descent. Cases included in the study were clinically evaluated for genetic generalised epilepsy. Whole-exome sequencing was done for the discovery case cohort, a validation case cohort, and two independent control cohorts. The replication case cohort underwent targeted next-generation sequencing of the 19 known genes encoding subunits of GABAA receptors and was compared to the respective GABAA receptor variants of a third independent control cohort. Functional investigations were done with automated two-microelectrode voltage clamping in Xenopus laevis oocytes. FINDINGS Statistical comparison of 152 familial index cases with genetic generalised epilepsy in the discovery cohort to 549 ethnically matched controls suggested an enrichment of rare missense (Nonsyn) variants in the ensemble of 19 genes encoding GABAA receptors in cases (odds ratio [OR] 2·40 [95% CI 1·41-4·10]; pNonsyn=0·0014, adjusted pNonsyn=0·019). Enrichment for these genes was validated in a whole-exome sequencing cohort of 357 sporadic and familial genetic generalised epilepsy cases and 1485 independent controls (OR 1·46 [95% CI 1·05-2·03]; pNonsyn=0·0081, adjusted pNonsyn=0·016). Comparison of genes encoding GABAA receptors in the independent replication cohort of 583 familial and sporadic genetic generalised epilepsy index cases, based on candidate-gene panel sequencing, with a third independent control cohort of 635 controls confirmed the overall enrichment of rare missense variants for 15 GABAA receptor genes in cases compared with controls (OR 1·46 [95% CI 1·02-2·08]; pNonsyn=0·013, adjusted pNonsyn=0·027). Functional studies for two selected genes (GABRB2 and GABRA5) showed significant loss-of-function effects with reduced current amplitudes in four of seven tested variants compared with wild-type receptors. INTERPRETATION Functionally relevant variants in genes encoding GABAA receptor subunits constitute a significant risk factor for genetic generalised epilepsy. Examination of the role of specific gene groups and pathways can disentangle the complex genetic architecture of genetic generalised epilepsy. FUNDING EuroEPINOMICS (European Science Foundation through national funding organisations), Epicure and EpiPGX (Sixth Framework Programme and Seventh Framework Programme of the European Commission), Research Unit FOR2715 (German Research Foundation and Luxembourg National Research Fund).
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Kothur K, Holman K, Farnsworth E, Ho G, Lorentzos M, Troedson C, Gupta S, Webster R, Procopis PG, Menezes MP, Antony J, Ardern-Holmes S, Dale RC, Christodoulou J, Gill D, Bennetts B. Diagnostic yield of targeted massively parallel sequencing in children with epileptic encephalopathy. Seizure 2018; 59:132-140. [DOI: 10.1016/j.seizure.2018.05.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 02/20/2018] [Accepted: 05/08/2018] [Indexed: 12/28/2022] Open
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19
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Clinical and genetic study of Tunisian families with genetic generalized epilepsy: contribution of CACNA1H and MAST4 genes. Neurogenetics 2018; 19:165-178. [PMID: 29948376 DOI: 10.1007/s10048-018-0550-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 06/01/2018] [Accepted: 06/03/2018] [Indexed: 12/11/2022]
Abstract
Genetic generalized epilepsies (GGE) (childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME) and epilepsy with generalized tonic-clonic seizures (GTCS)) are mainly determined by genetic factors. Since few mutations were identified in rare families with autosomal dominant GGE, a polygenic inheritance was suspected in most patients. Recent studies on large American or European cohorts of sporadic cases showed that susceptibility genes were numerous although their variants were rare, making their identification difficult. Here, we reported clinical and genetic characteristics of 30 Tunisian GGE families, including 71 GGE patients. The phenotype was close to that in sporadic cases. Nineteen pedigrees had a homogeneous type of GGE (JME-CAE-CGTS), and 11 combined these epileptic syndromes. Rare non-synonymous variants were selected in probands using a targeted panel of 30 candidate genes and their segregation was determined in families. Molecular studies incriminated different genes, mainly CACNA1H and MAST4. The segregation of at least two variants in different genes in some pedigrees was compatible with the hypothesis of an oligogenic inheritance, which was in accordance with the relatively low frequency of consanguineous probands. Since at least 2 susceptibility genes were likely shared by different populations, genetic factors involved in the majority of Tunisian GGE families remain to be discovered. Their identification should be easier in families with a homogeneous type of GGE, in which an intra-familial genetic homogeneity could be suspected.
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Bonzanni M, DiFrancesco JC, Milanesi R, Campostrini G, Castellotti B, Bucchi A, Baruscotti M, Ferrarese C, Franceschetti S, Canafoglia L, Ragona F, Freri E, Labate A, Gambardella A, Costa C, Rivolta I, Gellera C, Granata T, Barbuti A, DiFrancesco D. A novel de novo HCN1 loss-of-function mutation in genetic generalized epilepsy causing increased neuronal excitability. Neurobiol Dis 2018; 118:55-63. [PMID: 29936235 DOI: 10.1016/j.nbd.2018.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 11/26/2022] Open
Abstract
The causes of genetic epilepsies are unknown in the majority of patients. HCN ion channels have a widespread expression in neurons and increasing evidence demonstrates their functional involvement in human epilepsies. Among the four known isoforms, HCN1 is the most expressed in the neocortex and hippocampus and de novo HCN1 point mutations have been recently associated with early infantile epileptic encephalopathy. So far, HCN1 mutations have not been reported in patients with idiopathic epilepsy. Using a Next Generation Sequencing approach, we identified the de novo heterozygous p.Leu157Val (c.469C > G) novel mutation in HCN1 in an adult male patient affected by genetic generalized epilepsy (GGE), with normal cognitive development. Electrophysiological analysis in heterologous expression model (CHO cells) and in neurons revealed that L157V is a loss-of-function, dominant negative mutation causing reduced HCN1 contribution to net inward current and responsible for an increased neuronal firing rate and excitability, potentially predisposing to epilepsy. These data represent the first evidence that autosomal dominant missense mutations of HCN1 can also be involved in GGE, without the characteristics of epileptic encephalopathy reported previously. It will be important to include HCN1 screening in patients with GGE, in order to extend the knowledge of the genetic causes of idiopathic epilepsies, thus paving the way for the identification of innovative therapeutic strategies.
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Affiliation(s)
- Mattia Bonzanni
- Dept. of Biosciences, The PaceLab, University of Milano, Milano, Italy
| | - Jacopo C DiFrancesco
- Clinical Neurophysiology and Epilepsy Center, "C. Besta" Neurological Institute, Milano, Italy; Dept. of Neurology, San Gerardo Hospital, Laboratory of Neurobiology, Milan Center for Neuroscience, University of Milano-Bicocca, Monza, Italy.
| | | | | | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, "C. Besta" Neurological Institute, Milano, Italy
| | - Annalisa Bucchi
- Dept. of Biosciences, The PaceLab, University of Milano, Milano, Italy
| | - Mirko Baruscotti
- Dept. of Biosciences, The PaceLab, University of Milano, Milano, Italy
| | - Carlo Ferrarese
- Dept. of Neurology, San Gerardo Hospital, Laboratory of Neurobiology, Milan Center for Neuroscience, University of Milano-Bicocca, Monza, Italy
| | - Silvana Franceschetti
- Clinical Neurophysiology and Epilepsy Center, "C. Besta" Neurological Institute, Milano, Italy
| | - Laura Canafoglia
- Clinical Neurophysiology and Epilepsy Center, "C. Besta" Neurological Institute, Milano, Italy
| | - Francesca Ragona
- Dept. of Pediatric Neuroscience, "C. Besta" Neurological Institute, Milano, Italy
| | - Elena Freri
- Dept. of Pediatric Neuroscience, "C. Besta" Neurological Institute, Milano, Italy
| | - Angelo Labate
- Institute of Neurology, University "Magna Graecia", Catanzaro, Italy
| | | | - Cinzia Costa
- Neurology Unit, Department of Medicine, University of Perugia, Ospedale S. Maria della Misericordia, Perugia, Italy
| | - Ilaria Rivolta
- School of Medicine and Surgery, Milan Center for Neuroscience and Nanomedicine Center, University of Milano-Bicocca, Monza, Italy
| | - Cinzia Gellera
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, "C. Besta" Neurological Institute, Milano, Italy
| | - Tiziana Granata
- Dept. of Pediatric Neuroscience, "C. Besta" Neurological Institute, Milano, Italy
| | - Andrea Barbuti
- Dept. of Biosciences, The PaceLab, University of Milano, Milano, Italy.
| | - Dario DiFrancesco
- Dept. of Biosciences, The PaceLab, University of Milano, Milano, Italy
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Lee CG, Lee J, Lee M. Multi-gene panel testing in Korean patients with common genetic generalized epilepsy syndromes. PLoS One 2018; 13:e0199321. [PMID: 29924869 PMCID: PMC6010271 DOI: 10.1371/journal.pone.0199321] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
Genetic heterogeneity of common genetic generalized epilepsy syndromes is frequently considered. The present study conducted a focused analysis of potential candidate or susceptibility genes for common genetic generalized epilepsy syndromes using multi-gene panel testing with next-generation sequencing. This study included patients with juvenile myoclonic epilepsy, juvenile absence epilepsy, and epilepsy with generalized tonic-clonic seizures alone. We identified pathogenic variants according to the American College of Medical Genetics and Genomics guidelines and identified susceptibility variants using case-control association analyses and family analyses for familial cases. A total of 57 patients were enrolled, including 51 sporadic cases and 6 familial cases. Twenty-two pathogenic and likely pathogenic variants of 16 different genes were identified. CACNA1H was the most frequently observed single gene. Variants of voltage-gated Ca2+ channel genes, including CACNA1A, CACNA1G, and CACNA1H were observed in 32% of variants (n = 7/22). Analyses to identify susceptibility variants using case-control association analysis indicated that KCNMA1 c.400G>C was associated with common genetic generalized epilepsy syndromes. Only 1 family (family A) exhibited a candidate pathogenic variant p.(Arg788His) on CACNA1H, as determined via family analyses. This study identified candidate genetic variants in about a quarter of patients (n = 16/57) and an average of 2.8 variants was identified in each patient. The results reinforced the polygenic disorder with very high locus and allelic heterogeneity of common GGE syndromes. Further, voltage-gated Ca2+ channels are suggested as important contributors to common genetic generalized epilepsy syndromes. This study extends our comprehensive understanding of common genetic generalized epilepsy syndromes.
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Affiliation(s)
- Cha Gon Lee
- Department of Pediatrics, Nowon Eulji Medical Center, Eulji University, Seoul, Republic of Korea
| | - Jeehun Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
- * E-mail:
| | - Munhyang Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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22
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Koeleman BP. What do genetic studies tell us about the heritable basis of common epilepsy? Polygenic or complex epilepsy? Neurosci Lett 2018; 667:10-16. [DOI: 10.1016/j.neulet.2017.03.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 12/23/2022]
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23
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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van Eyk C, Corbett M, Maclennan A. The emerging genetic landscape of cerebral palsy. HANDBOOK OF CLINICAL NEUROLOGY 2018; 147:331-342. [DOI: 10.1016/b978-0-444-63233-3.00022-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Szepetowski P. Genetics of human epilepsies: Continuing progress. Presse Med 2017; 47:218-226. [PMID: 29277263 DOI: 10.1016/j.lpm.2017.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/24/2017] [Indexed: 01/06/2023] Open
Abstract
Numerous epilepsy genes have been identified in the last years, mostly in the (rare) monogenic forms and thanks to the increased availability and the decreased cost of next-generation sequencing approaches. Besides the somehow expected group of epilepsy genes encoding various ion channel subunits (e.g. sodium or potassium channel subunits, or GABA receptors, or glutamate-gated NMDA receptors), more diversity has emerged recently, with novel epilepsy genes encoding proteins playing a wide range of physiological roles at the cellular and molecular levels, such as synaptic proteins, members of the mTOR pathway, or proteins involved in chromatin remodeling. The overall picture is somehow complicated: one given epilepsy gene can be associated with more than one epileptic phenotype, and with variable degrees of severity, from the benign to the severe forms (e.g. epileptic encephalopathies), and with various comorbid conditions such as migraine or autism spectrum of disorders. Conversely, one given epileptic syndrome may be associated with different genes, some of which have obvious links with each other (e.g. encoding different subunits of the same receptor) while other ones have no clear relationships. Also genomic copy number variations have been detected, some of which, albeit rare, may confer high risk to epilepsy. Whereas translation from gene identification to targeted medicine still remains challenging, progress in epilepsy genetics is currently revolutionizing genetic-based diagnosis and genetic counseling. Epilepsy gene identification also represents a key entry point to start in deciphering the underlying pathophysiological mechanisms via the design and the study of the most pertinent cellular and animal models - which may in turn provide proofs-of-principle for future applications in human epilepsies.
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Affiliation(s)
- Pierre Szepetowski
- Mediterranean Institute of Neurobiology (INMED), Inserm U901, parc scientifique de Luminy, BP 13, 13273 Marseille cedex 09, France.
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Torres CM, Siebert M, Bock H, Mota SM, Krammer BR, Duarte JÁ, Bragatti JA, Castan JU, de Castro LA, Saraiva-Pereira ML, Bianchin MM. NTRK2 (TrkB gene) variants and temporal lobe epilepsy: A genetic association study. Epilepsy Res 2017; 137:1-8. [PMID: 28863320 DOI: 10.1016/j.eplepsyres.2017.08.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/14/2017] [Accepted: 08/19/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The NTRK2 gene encodes a member of the neurotrophic tyrosine kinase receptor family known as TrkB. It is a membrane-associated receptor with signaling and cellular differentiation properties that has been involved in neuropsychiatric disorders, including epilepsy. We report here the frequencies of NTRK2 allele variants in patients with temporal lobe epilepsy (TLE) compared to controls without epilepsy and explore the impact of these polymorphisms on major clinical variables in TLE. METHODS A case-control study comparing the frequencies of the NTRK2 gene polymorphisms beween 198 TLE Caucasian patients and 200 matching controls without epilepsy. In a second step, the impact of allelic variation on major clinical and electroencephalographic epilepsy variables was evaluated in the group of TLE patients. The following polymorphisms were determined by testing different regions of the NTRK2 gene: rs1867283, rs10868235, rs1147198, rs11140800, rs1187286, rs2289656, rs1624327, rs1443445, rs3780645, and rs2378672. To correct for multiple correlations the level of significance was set at p<0.01. RESULTS Patients with TLE showed a statistical trend for increase of the T/T genotype in rs10868235 compared to control (O.R.=1.90; 95%CI=1.17-3.09; p=0.01). Homozygous patients for the A allele in rs1443445 had earlier mean age at onset of seizures, p=0.009 (mean age of 16.6 versus 22.4years). We also observed that the T allele in rs3780645 was more frequent in patients who needed polytheraphy for seizure control than in patients on monotherapy, (O.R.=4.13; 95%CI=1.68-10.29; p=0.001). This finding may reflect an increased difficulty to obtain seizure control in this group of patients. No additional differences were observed in this study. CONCLUSIONS Patients with epilepsy showed a trend for a difference in rs10868235 allelic distribution compared to controls without epilepsy. NTRK2 variability influenced age at seizure onset and the pharmacological response to seizure control. As far as we know, this is the first study showing an association between NTKR2 allelic variants in human epilepsy. We believe that further studies in this venue will shade some light on the molecular mechanisms involved in epileptogenesis and in the clinical characteristics of epilepsy.
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Affiliation(s)
- Carolina Machado Torres
- Graduate Program in Medical Science, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil; Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil
| | - Marina Siebert
- Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Hugo Bock
- Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Suelen Mandelli Mota
- Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Bárbara Reis Krammer
- Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Juliana Ávila Duarte
- Graduate Program in Medical Science, Universidade Federal do Rio Grande do Sul, Brazil; Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Brazil
| | - José Augusto Bragatti
- Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil
| | - Juliana Unis Castan
- Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil
| | - Luiza Amaral de Castro
- Graduate Program in Medical Science, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Maria Luiza Saraiva-Pereira
- Graduate Program in Medical Science, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil; Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Marino Muxfeldt Bianchin
- Graduate Program in Medical Science, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil; Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil.
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Becker F, Reid CA, Hallmann K, Tae HS, Phillips AM, Teodorescu G, Weber YG, Kleefuss-Lie A, Elger C, Perez-Reyes E, Petrou S, Kunz WS, Lerche H, Maljevic S. Functional variants in HCN4 and CACNA1H may contribute to genetic generalized epilepsy. Epilepsia Open 2017; 2:334-342. [PMID: 29588962 PMCID: PMC5862120 DOI: 10.1002/epi4.12068] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2017] [Indexed: 01/11/2023] Open
Abstract
Objective Genetic generalized epilepsy (GGE) encompasses seizure disorders characterized by spike‐and‐wave discharges (SWD) originating within thalamo‐cortical circuits. Hyperpolarization‐activated (HCN) and T‐type Ca2+ channels are key modulators of rhythmic activity in these brain regions. Here, we screened HCN4 and CACNA1H genes for potentially contributory variants and provide their functional analysis. Methods Targeted gene sequencing was performed in 20 unrelated familial cases with different subtypes of GGE, and the results confirmed in 230 ethnically matching controls. Selected variants in CACNA1H and HCN4 were functionally assessed in tsA201 cells and Xenopus laevis oocytes, respectively. Results We discovered a novel CACNA1H (p.G1158S) variant in two affected members of a single family. One of them also carried an HCN4 (p.P1117L) variant inherited from the unaffected mother. In a separate family, an HCN4 variant (p.E153G) was identified in one of several affected members. Voltage‐clamp analysis of CACNA1H (p.G1158S) revealed a small but significant gain‐of‐function, including increased current density and a depolarizing shift of steady‐state inactivation. HCN4 p.P1117L and p.G153E both caused a hyperpolarizing shift in activation and reduced current amplitudes, resulting in a loss‐of‐function. Significance Our results are consistent with a model suggesting cumulative contributions of subtle functional variations in ion channels to seizure susceptibility and GGE.
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Affiliation(s)
- Felicitas Becker
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,RKU-University Neurology Clinic of Ulm Ulm Germany
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Kerstin Hallmann
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Han-Shen Tae
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,Present address: Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong Wollongong New South Wales Australia
| | - A Marie Phillips
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,School of Biosciences The University of Melbourne Melbourne Victoria Australia
| | - Georgeta Teodorescu
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Yvonne G Weber
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Ailing Kleefuss-Lie
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Christian Elger
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Edward Perez-Reyes
- Department of Pharmacology University of Virginia Charlottesville Virginia U.S.A
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Wolfram S Kunz
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Holger Lerche
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Snezana Maljevic
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
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GPR37L1 modulates seizure susceptibility: Evidence from mouse studies and analyses of a human GPR37L1 variant. Neurobiol Dis 2017; 106:181-190. [PMID: 28688853 DOI: 10.1016/j.nbd.2017.07.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/23/2017] [Accepted: 07/04/2017] [Indexed: 12/28/2022] Open
Abstract
Progressive myoclonus epilepsies (PMEs) are disorders characterized by myoclonic and generalized seizures with progressive neurological deterioration. While several genetic causes for PMEs have been identified, the underlying causes remain unknown for a substantial portion of cases. Here we describe several affected individuals from a large, consanguineous family presenting with a novel PME in which symptoms begin in adolescence and result in death by early adulthood. Whole exome analyses revealed that affected individuals have a homozygous variant in GPR37L1 (c.1047G>T [Lys349Asn]), an orphan G protein-coupled receptor (GPCR) expressed predominantly in the brain. In vitro studies demonstrated that the K349N substitution in Gpr37L1 did not grossly alter receptor expression, surface trafficking or constitutive signaling in transfected cells. However, in vivo studies revealed that a complete loss of Gpr37L1 function in mice results in increased seizure susceptibility. Mice lacking the related receptor Gpr37 also exhibited an increase in seizure susceptibility, while genetic deletion of both receptors resulted in an even more dramatic increase in vulnerability to seizures. These findings provide evidence linking GPR37L1 and GPR37 to seizure etiology and demonstrate an association between a GPR37L1 variant and a novel progressive myoclonus epilepsy.
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29
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Musgaard M, Paramo T, Domicevica L, Andersen OJ, Biggin PC. Insights into channel dysfunction from modelling and molecular dynamics simulations. Neuropharmacology 2017; 132:20-30. [PMID: 28669899 DOI: 10.1016/j.neuropharm.2017.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 06/06/2017] [Accepted: 06/28/2017] [Indexed: 11/20/2022]
Abstract
Developments in structural biology mean that the number of different ion channel structures has increased significantly in recent years. Structures of ion channels enable us to rationalize how mutations may lead to channelopathies. However, determining the structures of ion channels is still not trivial, especially as they necessarily exist in many distinct functional states. Therefore, the use of computational modelling can provide complementary information that can refine working hypotheses of both wild type and mutant ion channels. The simplest but still powerful tool is homology modelling. Many structures are available now that can provide suitable templates for many different types of ion channels, allowing a full three-dimensional interpretation of mutational effects. These structural models, and indeed the structures themselves obtained by X-ray crystallography, and more recently cryo-electron microscopy, can be subjected to molecular dynamics simulations, either as a tool to help explore the conformational dynamics in detail or simply as a means to refine the models further. Here we review how these approaches have been used to improve our understanding of how diseases might be linked to specific mutations in ion channel proteins. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Maria Musgaard
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Teresa Paramo
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Laura Domicevica
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Ole Juul Andersen
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Philip C Biggin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
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30
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dos Santos BP, Marinho CRM, Marques TEBS, Angelo LKG, Malta MVDS, Duzzioni M, de Castro OW, Leite JP, Barbosa FT, Gitaí DLG. Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies. PLoS One 2017; 12:e0179629. [PMID: 28636645 PMCID: PMC5479548 DOI: 10.1371/journal.pone.0179629] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Several genetic association investigations have been performed over the last three decades to identify variants underlying Juvenile Myoclonic Epilepsy (JME). Here, we evaluate the accumulating findings and provide an updated perspective of these studies. METHODOLOGY A systematic literature search was conducted using the PubMed, Embase, Scopus, Lilacs, epiGAD, Google Scholar and Sigle up to February 12, 2016. The quality of the included studies was assessed by a score and classified as low and high quality. Beyond outcome measures, information was extracted on the setting for each study, characteristics of population samples and polymorphisms. RESULTS Fifty studies met eligibility criteria and were used for data extraction. With a single exception, all studies used a candidate gene approach, providing data on 229 polymorphisms in or near 55 different genes. Of variants investigating in independent data sets, only rs2029461 SNP in GRM4, rs3743123 in CX36 and rs3918149 in BRD2 showed a significant association with JME in at least two different background populations. The lack of consistent associations might be due to variations in experimental design and/or limitations of the approach. CONCLUSIONS Thus, despite intense research evidence established, specific genetic variants in JME susceptibility remain inconclusive. We discussed several issues that may compromise the quality of the results, including methodological bias, endophenotype and potential involvement of epigenetic factors. PROSPERO REGISTRATION NUMBER CRD42016036063.
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Affiliation(s)
- Bruna Priscila dos Santos
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Chiara Rachel Maciel Marinho
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | | | - Layanne Kelly Gomes Angelo
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Maísa Vieira da Silva Malta
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Marcelo Duzzioni
- Department of Pharmacology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Olagide Wagner de Castro
- Department of Physiology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - João Pereira Leite
- Division of Neurology, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Daniel Leite Góes Gitaí
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
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Wang S, Li L, Tao R, Gao Y. Ion channelopathies associated genetic variants as the culprit for sudden unexplained death. Forensic Sci Int 2017; 275:128-137. [PMID: 28363160 DOI: 10.1016/j.forsciint.2017.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/23/2017] [Accepted: 03/13/2017] [Indexed: 11/29/2022]
Abstract
Forensic identification of sudden unexplained death (SUD) has always been a ticklish issue because it used to be defined as sudden death without a conclusive diagnosis after autopsy. However, benefiting from the developments in genome research, a growing body of evidence points to the importance of ion channelopathies associated genetic variants in the pathogenesis of SUD. Genetic diagnosis of the deceased is also a new trend in epidemiological studies, for it enables the undertaking for preventive approach in individuals with high risks. In this review, we briefly discuss the molecular structure of ion channels and the role of genetic variants in regulating their functions as well as the diverse mechanisms underlying the ion channelopathies at gene level.
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Affiliation(s)
- Shouyu Wang
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Lijuan Li
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Ruiyang Tao
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Yuzhen Gao
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China.
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Chen T, Giri M, Xia Z, Subedi YN, Li Y. Genetic and epigenetic mechanisms of epilepsy: a review. Neuropsychiatr Dis Treat 2017; 13:1841-1859. [PMID: 28761347 PMCID: PMC5516882 DOI: 10.2147/ndt.s142032] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Epilepsy is a common episodic neurological disorder or condition characterized by recurrent epileptic seizures, and genetics seems to play a key role in its etiology. Early linkage studies have localized multiple loci that may harbor susceptibility genes to epilepsy, and mutational analyses have detected a number of mutations involved in both ion channel and nonion channel genes in patients with idiopathic epilepsy. Genome-wide studies of epilepsy have found copy number variants at 2q24.2-q24.3, 7q11.22, 15q11.2-q13.3, and 16p13.11-p13.2, some of which disrupt multiple genes, such as NRXN1, AUTS2, NLGN1, CNTNAP2, GRIN2A, PRRT2, NIPA2, and BMP5, implicated for neurodevelopmental disorders, including intellectual disability and autism. Unfortunately, only a few common genetic variants have been associated with epilepsy. Recent exome-sequencing studies have found some genetic mutations, most of which are located in nonion channel genes such as the LGI1, PRRT2, EFHC1, PRICKLE, RBFOX1, and DEPDC5 and in probands with rare forms of familial epilepsy, and some of these genes are involved with the neurodevelopment. Since epigenetics plays a role in neuronal function from embryogenesis and early brain development to tissue-specific gene expression, epigenetic regulation may contribute to the genetic mechanism of neurodevelopment through which a gene and the environment interacting with each other affect the development of epilepsy. This review focused on the analytic tools used to identify epilepsy and then provided a summary of recent linkage and association findings, indicating the existence of novel genes on several chromosomes for further understanding of the biology of epilepsy.
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Affiliation(s)
- Tian Chen
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Mohan Giri
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Zhenyi Xia
- Department of Thoracic Surgery, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Yadu Nanda Subedi
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Yan Li
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
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Marini S, Limongelli I, Rizzo E, Malovini A, Errichiello E, Vetro A, Da T, Zuffardi O, Bellazzi R. A Data Fusion Approach to Enhance Association Study in Epilepsy. PLoS One 2016; 11:e0164940. [PMID: 27984588 PMCID: PMC5161322 DOI: 10.1371/journal.pone.0164940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 10/04/2016] [Indexed: 11/25/2022] Open
Abstract
Among the scientific challenges posed by complex diseases with a strong genetic component, two stand out. One is unveiling the role of rare and common genetic variants; the other is the design of classification models to improve clinical diagnosis and predictive models for prognosis and personalized therapies. In this paper, we present a data fusion framework merging gene, domain, pathway and protein-protein interaction data related to a next generation sequencing epilepsy gene panel. Our method allows integrating association information from multiple genomic sources and aims at highlighting the set of common and rare variants that are capable to trigger the occurrence of a complex disease. When compared to other approaches, our method shows better performances in classifying patients affected by epilepsy.
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Affiliation(s)
- Simone Marini
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Kyoto, Japan
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
- * E-mail: ,
| | - Ivan Limongelli
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- enGenome S.r.l., Via Ferrata 5, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
| | - Ettore Rizzo
- enGenome S.r.l., Via Ferrata 5, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
| | | | | | - Annalisa Vetro
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Tan Da
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Orsetta Zuffardi
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Riccardo Bellazzi
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
- IRCCS Fondazione S. Maugeri, Pavia, Italy
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Oh SH, Baek J, Kim KM, Lee EJ, Jung Y, Lee YJ, Jin HS, Ye BD, Yang SK, Lee JK, Seo EJ, Lim HT, Lee I, Song K. Is Whole Exome Sequencing Clinically Practical in the Management of Pediatric Crohn's Disease? Gut Liver 2016; 9:767-75. [PMID: 26503572 PMCID: PMC4625707 DOI: 10.5009/gnl15176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background/Aims The aim of this study was to identify the profile of rare variants associated with Crohn’s disease (CD) using whole exome sequencing (WES) analysis of Korean children with CD and to evaluate whether genetic profiles could provide information during medical decision making. Methods DNA samples from 18 control individuals and 22 patients with infantile, very-early and early onset CD of severe phenotype were used for WES. Genes were filtered using panels of inflammatory bowel disease (IBD)-associated genes and genes of primary immunodeficiency (PID) and monogenic IBD. Results Eighty-one IBD-associated variants and 35 variants in PID genes were revealed by WES. The most frequently occurring variants were carried by nine (41%) and four (18.2%) CD probands and were ATG16L2 (rs11235604) and IL17REL (rs142430606), respectively. Twenty-four IBD-associated variants and 10 PID variants were predicted to be deleterious and were identified in the heterozygous state. However, their functions were unknown with the exception of a novel p.Q111X variant in XIAP (X chromosome) of a male proband. Conclusions The presence of many rare variants of unknown significance limits the clinical applicability of WES for individual CD patients. However, WES in children may be beneficial for distinguishing CD secondary to PID.
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Affiliation(s)
- Seak Hee Oh
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Jiwon Baek
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyung Mo Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Eun-Ju Lee
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Yusun Jung
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Yeoun Joo Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyun-Seung Jin
- Department of Pediatrics, GangNeung Asan Hospital, Gangneung, Seoul, Korea
| | - Byong Duk Ye
- Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Suk-Kyun Yang
- Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jong-Keuk Lee
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Korea
| | - Eul-Ju Seo
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyun Taek Lim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Inchul Lee
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyuyoung Song
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
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Ehaideb SN, Wignall EA, Kasuya J, Evans WH, Iyengar A, Koerselman HL, Lilienthal AJ, Bassuk AG, Kitamoto T, Manak JR. Mutation of orthologous prickle genes causes a similar epilepsy syndrome in flies and humans. Ann Clin Transl Neurol 2016; 3:695-707. [PMID: 27648459 PMCID: PMC5018582 DOI: 10.1002/acn3.334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/24/2016] [Accepted: 06/27/2016] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE Genetically tractable fruit flies have been used for decades to study seizure disorders. However, there is a paucity of data specifically correlating fly and human seizure phenotypes. We have previously shown that mutation of orthologous PRICKLE genes from flies to humans produce seizures. This study aimed to determine whether the prickle-mediated seizure phenotypes in flies closely parallel the epilepsy syndrome found in PRICKLE patients. METHODS Virtually all fly seizure studies have relied upon characterizing seizures that are evoked. We have developed two novel approaches to more precisely characterize seizure-related phenotypes in their native state in prickle mutant flies. First, we used high-resolution videography to document spontaneous, unprovoked seizure events. Second, we developed a locomotion coordination assay to assess whether the prickle mutant flies were ataxic. Third, we treated the mutant flies with levetiracetam to determine whether the behavioral phenotypes could be suppressed by a common antiepileptic drug. RESULTS We find that the prickle mutant flies exhibit myoclonic-like spontaneous seizure events and are severely ataxic. Both these phenotypes are found in human patients with PRICKLE mutations, and can be suppressed by levetiracetam, providing evidence that the phenotypes are due to neurological dysfunction. These results document for the first time spontaneous, unprovoked seizure events at high resolution in a fly human seizure disorder model, capturing seizures in their native state. INTERPRETATION Collectively, these data underscore the striking similarities between the fly and human PRICKLE-mediated epilepsy syndromes, and provide a genetically tractable model for dissecting the underlying causes of the human syndromic phenotypes.
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Affiliation(s)
- Salleh N Ehaideb
- Interdisciplinary Graduate Program in Genetics University of Iowa Iowa City Iowa; King Abdullah International Medical Research Cente rKing Abdulaziz Medical City Riyadh Saudi Arabia; Department of Biology University of Iowa Iowa City Iowa
| | | | - Junko Kasuya
- Department of Anesthesia University of Iowa Iowa City Iowa
| | | | - Atulya Iyengar
- Department of Biology University of Iowa Iowa City Iowa; Interdisciplinary Graduate Program in Neuroscience University of Iowa Iowa City Iowa
| | | | | | | | - Toshihiro Kitamoto
- Interdisciplinary Graduate Program in Genetics University of Iowa Iowa City Iowa; Department of Anesthesia University of Iowa Iowa City Iowa; Interdisciplinary Graduate Program in Neuroscience University of Iowa Iowa City Iowa
| | - J Robert Manak
- Interdisciplinary Graduate Program in Genetics University of Iowa Iowa City Iowa; Department of Biology University of Iowa Iowa City Iowa; Interdisciplinary Graduate Program in Neuroscience University of Iowa Iowa City Iowa; Department of Pediatrics University of Iowa Iowa City Iowa
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36
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Long D, Deng X, Singh P, Loeb M, Lauring AS, Seielstad M. Identification of genetic variants associated with susceptibility to West Nile virus neuroinvasive disease. Genes Immun 2016; 17:298-304. [PMID: 27170560 PMCID: PMC5215919 DOI: 10.1038/gene.2016.21] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/10/2016] [Accepted: 04/12/2016] [Indexed: 11/09/2022]
Abstract
West Nile virus (WNV) infection results in a diverse spectrum of outcomes, and host genetics are likely to influence susceptibility to neuroinvasive disease (West Nile neuroinvasive disease (WNND)). We performed whole-exome sequencing of 44 individuals with WNND and identified alleles associated with severe disease by variant filtration in cases, kernel association testing in cases and controls and single-nucleotide polymorphism (SNP) imputation into a larger cohort of WNND cases and seropositive controls followed by genome-wide association analysis. Variant filtration prioritized genes based on the enrichment of otherwise rare variants, but did not unambiguously implicate variants shared by a majority of cases. Kernel association demonstrated enrichment for risk and protective alleles in the human leukocyte antigen (HLA)-A and HLA-DQB1 loci that have well understood roles in antiviral immunity. Two loci, HERC5 and an intergenic region between CD83 and JARID2, were implicated by multiple imputed SNPs and exceeded genome-wide significance in a discovery cohort (n=862). SNPs at two additional loci, TFCP2L1 and CACNA1H, achieved genome-wide significance after association testing of directly genotyped and imputed SNPs in a discovery cohort (n=862) and a separate replication cohort (n=1387). The context of these loci suggests that immunoregulatory, ion channel and endothelial barrier functions may be important elements of the host response to WNV.
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Affiliation(s)
- D Long
- School of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - X Deng
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
- Blood Systems Research Institute, San Francisco, CA, USA
| | - P Singh
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - M Loeb
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - A S Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - M Seielstad
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
- Blood Systems Research Institute, San Francisco, CA, USA
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Loss of function of the retinoid-related nuclear receptor (RORB) gene and epilepsy. Eur J Hum Genet 2016; 24:1761-1770. [PMID: 27352968 DOI: 10.1038/ejhg.2016.80] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 05/01/2016] [Accepted: 05/20/2016] [Indexed: 12/11/2022] Open
Abstract
Genetic generalized epilepsy (GGE), formerly known as idiopathic generalized epilepsy, is the most common form of epilepsy and is thought to have predominant genetic etiology. GGE are clinically characterized by absence, myoclonic, or generalized tonic-clonic seizures with electroencephalographic pattern of bilateral, synchronous, and symmetrical spike-and-wave discharges. Despite their strong heritability, the genetic basis of generalized epilepsies remains largely elusive. Nevertheless, recent advances in genetic technology have led to the identification of numerous genes and genomic defects in various types of epilepsies in the past few years. In the present study, we performed whole-exome sequencing in a family with GGE consistent with the diagnosis of eyelid myoclonia with absences. We found a nonsense variant (c.196C>T/p.(Arg66*)) in RORB, which encodes the beta retinoid-related orphan nuclear receptor (RORβ), in four affected family members. In addition, two de novo variants (c.218T>C/p.(Leu73Pro); c.1249_1251delACG/p.(Thr417del)) were identified in sporadic patients by trio-based exome sequencing. We also found two de novo deletions in patients with behavioral and cognitive impairment and epilepsy: a 52-kb microdeletion involving exons 5-10 of RORB and a larger 9q21-microdeletion. Furthermore, we identified a patient with intellectual disability and a balanced translocation where one breakpoint truncates RORB and refined the phenotype of a recently reported patient with RORB deletion. Our data support the role of RORB gene variants/CNVs in neurodevelopmental disorders including epilepsy, and especially in generalized epilepsies with predominant absence seizures.
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38
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Advancing epilepsy treatment through personalized genetic zebrafish models. PROGRESS IN BRAIN RESEARCH 2016; 226:195-207. [PMID: 27323944 DOI: 10.1016/bs.pbr.2016.03.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With an increase in the number of disease causing genetic mutations identified from epilepsy cohorts, zebrafish are proving to be an attractive vertebrate model for functional analysis of these allele variants. Not only do zebrafish have conserved gene functions, but larvae harboring mutations in identified human epileptic genes show spontaneous seizure activity and mimic the convulsive behavioral movements observed in humans. With zebrafish being compatible with medium to high-throughput screening, they are also proving to be a unique and powerful system for early preclinical drug screening, including novel target identification, pharmacology, and toxicology. Additionally, with recent advances in genomic engineering technologies, it is now possible to study the precise pathophysiology of patient-specific gene mutations in zebrafish. The following sections highlight how the unique attributes of zebrafish, in combination with genetic modifications, are continuing to transform our understanding of epilepsy and help identify personalized therapeutics for specific patient cohorts.
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39
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Genetic data: The new challenge of personalized medicine, insights for rheumatoid arthritis patients. Gene 2016; 583:90-101. [PMID: 26869316 DOI: 10.1016/j.gene.2016.02.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 01/18/2016] [Accepted: 02/05/2016] [Indexed: 01/15/2023]
Abstract
Rapid advances in genotyping technology, analytical methods, and the establishment of large cohorts for population genetic studies have resulted in a large new body of information about the genetic basis of human rheumatoid arthritis (RA). Improved understanding of the root pathogenesis of the disease holds the promise of improved diagnostic and prognostic tools based upon this information. In this review, we summarize the nature of new genetic findings in human RA, including susceptibility loci and gene-gene and gene-environment interactions, as well as genetic loci associated with sub-groups of patients and those associated with response to therapy. Possible uses of these data are discussed, such as prediction of disease risk as well as personalized therapy and prediction of therapeutic response and risk of adverse events. While these applications are largely not refined to the point of clinical utility in RA, it seems likely that multi-parameter datasets including genetic, clinical, and biomarker data will be employed in the future care of RA patients.
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40
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Spillane J, Kullmann DM, Hanna MG. Genetic neurological channelopathies: molecular genetics and clinical phenotypes. J Neurol Neurosurg Psychiatry 2016; 87:37-48. [PMID: 26558925 PMCID: PMC4717447 DOI: 10.1136/jnnp-2015-311233] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 09/13/2015] [Indexed: 01/08/2023]
Abstract
Evidence accumulated over recent years has shown that genetic neurological channelopathies can cause many different neurological diseases. Presentations relating to the brain, spinal cord, peripheral nerve or muscle mean that channelopathies can impact on almost any area of neurological practice. Typically, neurological channelopathies are inherited in an autosomal dominant fashion and cause paroxysmal disturbances of neurological function, although the impairment of function can become fixed with time. These disorders are individually rare, but an accurate diagnosis is important as it has genetic counselling and often treatment implications. Furthermore, the study of less common ion channel mutation-related diseases has increased our understanding of pathomechanisms that is relevant to common neurological diseases such as migraine and epilepsy. Here, we review the molecular genetic and clinical features of inherited neurological channelopathies.
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Affiliation(s)
- J Spillane
- Royal Free Hospital Foundation Trust London, London, UK MRC Centre for Neuromuscular Disease, UCL, London, UK
| | - D M Kullmann
- MRC Centre for Neuromuscular Disease, UCL, London, UK UCL, Institute of Neurology, London, UK
| | - M G Hanna
- MRC Centre for Neuromuscular Disease, UCL, London, UK UCL, Institute of Neurology, London, UK
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41
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Møller RS, Dahl HA, Helbig I. The contribution of next generation sequencing to epilepsy genetics. Expert Rev Mol Diagn 2015; 15:1531-8. [DOI: 10.1586/14737159.2015.1113132] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Knott S, Forty L, Craddock N, Thomas RH. Epilepsy and bipolar disorder. Epilepsy Behav 2015; 52:267-74. [PMID: 26316422 DOI: 10.1016/j.yebeh.2015.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/25/2015] [Accepted: 07/02/2015] [Indexed: 01/30/2023]
Abstract
It is well recognized that mood disorders and epilepsy commonly co-occur. Despite this, our knowledge regarding the relationship between epilepsy and bipolar disorder is limited. Several shared features between the two disorders, such as their episodic nature and potential to run a chronic course, and the efficacy of some antiepileptic medications in the prophylaxis of both disorders, are often cited as evidence of possible shared underlying pathophysiology. The present paper aims to review the bidirectional associations between epilepsy and bipolar disorder, with a focus on epidemiological links, evidence for shared etiology, and the impact of these disorders on both the individual and wider society. Better recognition and understanding of these two complex disorders, along with an integrated clinical approach, are crucial for improved evaluation and management of comorbid epilepsy and mood disorders.
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Affiliation(s)
- Sarah Knott
- MRC Centre for Neuropsychiatric Genetics and Genomics, Haydn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK.
| | - Liz Forty
- MRC Centre for Neuropsychiatric Genetics and Genomics, Haydn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK.
| | - Nick Craddock
- MRC Centre for Neuropsychiatric Genetics and Genomics, Haydn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK.
| | - Rhys H Thomas
- MRC Centre for Neuropsychiatric Genetics and Genomics, Haydn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK.
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Genetic Architecture of Complex Human Traits: What Have We Learned from Genome-Wide Association Studies? CURRENT GENETIC MEDICINE REPORTS 2015. [DOI: 10.1007/s40142-015-0083-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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Disruption of Fgf13 causes synaptic excitatory-inhibitory imbalance and genetic epilepsy and febrile seizures plus. J Neurosci 2015; 35:8866-81. [PMID: 26063919 DOI: 10.1523/jneurosci.3470-14.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We identified a family in which a translocation between chromosomes X and 14 was associated with cognitive impairment and a complex genetic disorder termed "Genetic Epilepsy and Febrile Seizures Plus" (GEFS(+)). We demonstrate that the breakpoint on the X chromosome disrupted a gene that encodes an auxiliary protein of voltage-gated Na(+) channels, fibroblast growth factor 13 (Fgf13). Female mice in which one Fgf13 allele was deleted exhibited hyperthermia-induced seizures and epilepsy. Anatomic studies revealed expression of Fgf13 mRNA in both excitatory and inhibitory neurons of hippocampus. Electrophysiological recordings revealed decreased inhibitory and increased excitatory synaptic inputs in hippocampal neurons of Fgf13 mutants. We speculate that reduced expression of Fgf13 impairs excitability of inhibitory interneurons, resulting in enhanced excitability within local circuits of hippocampus and the clinical phenotype of epilepsy. These findings reveal a novel cause of this syndrome and underscore the powerful role of FGF13 in control of neuronal excitability.
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46
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Lesca G, Depienne C. Epilepsy genetics: the ongoing revolution. Rev Neurol (Paris) 2015; 171:539-57. [PMID: 26003806 DOI: 10.1016/j.neurol.2015.01.569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/24/2014] [Accepted: 01/20/2015] [Indexed: 01/04/2023]
Abstract
Epilepsies have long remained refractory to gene identification due to several obstacles, including a highly variable inter- and intrafamilial expressivity of the phenotypes, a high frequency of phenocopies, and a huge genetic heterogeneity. Recent technological breakthroughs, such as array comparative genomic hybridization and next generation sequencing, have been leading, in the past few years, to the identification of an increasing number of genomic regions and genes in which mutations or copy-number variations cause various epileptic disorders, revealing an enormous diversity of pathophysiological mechanisms. The field that has undergone the most striking revolution is that of epileptic encephalopathies, for which most of causing genes have been discovered since the year 2012. Some examples are the continuous spike-and-waves during slow-wave sleep and Landau-Kleffner syndromes for which the recent discovery of the role of GRIN2A mutations has finally confirmed the genetic bases. These new technologies begin to be used for diagnostic applications, and the main challenge now resides in the interpretation of the huge mass of variants detected by these methods. The identification of causative mutations in epilepsies provides definitive confirmation of the clinical diagnosis, allows accurate genetic counselling, and sometimes permits the development of new appropriate and specific antiepileptic therapies. Future challenges include the identification of the genetic or environmental factors that modify the epileptic phenotypes caused by mutations in a given gene and the understanding of the role of somatic mutations in sporadic epilepsies.
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Affiliation(s)
- G Lesca
- Service de génétique, groupement hospitalier Est, hospices civils de Lyon, 59, boulevard Pinel, 69677 Bron, France; Université Claude-Bernard Lyon 1, 43, boulevard du 11-Novembre-1918, 69100 Villeurbanne, France; CRNL, CNRS UMR 5292, Inserm U1028, bâtiment IMBL, 11, avenue Jean-Capelle, 69621 Villeurbanne cedex, France.
| | - C Depienne
- Département de génétique et cytogénétique, hôpital Pitié-Salpêtrière, AP-HP, 47-83, boulevard de l'Hôpital, 75651 Paris cedex 13, France; Sorbonne universités, UPMC université Paris 06, 4, place Jussieu, 75005 Paris, France; ICM, CNRS UMR 7225, Inserm U1127, 47, boulevard de l'Hôpital, 75651 Paris cedex 13, France
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47
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Galizia EC, Myers CT, Leu C, de Kovel CGF, Afrikanova T, Cordero-Maldonado ML, Martins TG, Jacmin M, Drury S, Krishna Chinthapalli V, Muhle H, Pendziwiat M, Sander T, Ruppert AK, Møller RS, Thiele H, Krause R, Schubert J, Lehesjoki AE, Nürnberg P, Lerche H, Palotie A, Coppola A, Striano S, Gaudio LD, Boustred C, Schneider AL, Lench N, Jocic-Jakubi B, Covanis A, Capovilla G, Veggiotti P, Piccioli M, Parisi P, Cantonetti L, Sadleir LG, Mullen SA, Berkovic SF, Stephani U, Helbig I, Crawford AD, Esguerra CV, Kasteleijn-Nolst Trenité DGA, Koeleman BPC, Mefford HC, Scheffer IE, Sisodiya SM. CHD2 variants are a risk factor for photosensitivity in epilepsy. Brain 2015; 138:1198-207. [PMID: 25783594 PMCID: PMC4407192 DOI: 10.1093/brain/awv052] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/07/2015] [Indexed: 12/24/2022] Open
Abstract
Photosensitivity in epilepsy is common and has high heritability, but its genetic basis remains uncertain. Galizia et al. reveal an overrepresentation of unique variants of CHD2 — which encodes the transcriptional regulator ‘chromodomain helicase DNA-binding protein 2’ — in photosensitive epilepsies, and show that chd2 knockdown in zebrafish causes photosensitivity. Photosensitivity is a heritable abnormal cortical response to flickering light, manifesting as particular electroencephalographic changes, with or without seizures. Photosensitivity is prominent in a very rare epileptic encephalopathy due to de novo CHD2 mutations, but is also seen in epileptic encephalopathies due to other gene mutations. We determined whether CHD2 variation underlies photosensitivity in common epilepsies, specific photosensitive epilepsies and individuals with photosensitivity without seizures. We studied 580 individuals with epilepsy and either photosensitive seizures or abnormal photoparoxysmal response on electroencephalography, or both, and 55 individuals with photoparoxysmal response but no seizures. We compared CHD2 sequence data to publicly available data from 34 427 individuals, not enriched for epilepsy. We investigated the role of unique variants seen only once in the entire data set. We sought CHD2 variants in 238 exomes from familial genetic generalized epilepsies, and in other public exome data sets. We identified 11 unique variants in the 580 individuals with photosensitive epilepsies and 128 unique variants in the 34 427 controls: unique CHD2 variation is over-represented in cases overall (P = 2·17 × 10−5). Among epilepsy syndromes, there was over-representation of unique CHD2 variants (3/36 cases) in the archetypal photosensitive epilepsy syndrome, eyelid myoclonia with absences (P = 3·50 × 10−4). CHD2 variation was not over-represented in photoparoxysmal response without seizures. Zebrafish larvae with chd2 knockdown were tested for photosensitivity. Chd2 knockdown markedly enhanced mild innate zebrafish larval photosensitivity. CHD2 mutation is the first identified cause of the archetypal generalized photosensitive epilepsy syndrome, eyelid myoclonia with absences. Unique CHD2 variants are also associated with photosensitivity in common epilepsies. CHD2 does not encode an ion channel, opening new avenues for research into human cortical excitability.
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Affiliation(s)
- Elizabeth C Galizia
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | | | - Costin Leu
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Carolien G F de Kovel
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | - Tatiana Afrikanova
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | - Teresa G Martins
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Maxime Jacmin
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Suzanne Drury
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - V Krishna Chinthapalli
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Hiltrud Muhle
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Manuela Pendziwiat
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Thomas Sander
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | | | - Rikke S Møller
- 9 Danish Epilepsy Centre, Dianalund, Denmark 10 Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Holger Thiele
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Roland Krause
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Julian Schubert
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | - Anna-Elina Lehesjoki
- 12 Folkhälsan Institute of Genetics and Neuroscience Centre, University of Helsinki, Helsinki, Finland 13 Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Peter Nürnberg
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Holger Lerche
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | | | - Aarno Palotie
- 14 Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, UK 15 Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland 16 Program in Medical and Population Genetics and Genetic Analysis Platform, The Broad Institute of MIT and Harvard, Cambridge, USA
| | - Antonietta Coppola
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Salvatore Striano
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Luigi Del Gaudio
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Christopher Boustred
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Amy L Schneider
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Nicholas Lench
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Bosanka Jocic-Jakubi
- 19 Department of Child Neurology, Paediatric Clinic, Clinical Centre Nis, Serbia 20 Department of Paediatric Neurology, Paediatric Clinic, Al Sabah Hospital, Kuwait
| | - Athanasios Covanis
- 21 Neurology Department, The Children's Hospital Agia Sophia, Athens, Greece
| | | | - Pierangelo Veggiotti
- 23 Department of Child Neurology and Psychiatry C. Mondino National Neurological Institute, Via Mondino, 2, 27100, Pavia, Italy 24 Brain and Behaviour Department, University of Pavia, Pavia, Italy
| | - Marta Piccioli
- 25 Neurophysiopathology Unit, San Filippo Neri Hospital, Rome, Italy
| | - Pasquale Parisi
- 26 Child Neurology, NESMOS Department, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Laura Cantonetti
- 27 Neurorehabilitation Unit, Department of Neuroscience and Neurorehabilitation, IRCCS, Bambino Gesu' Children's Hospital, Rome, Italy
| | - Lynette G Sadleir
- 28 Department of Paediatrics and Child Health, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Saul A Mullen
- 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Samuel F Berkovic
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Ulrich Stephani
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Ingo Helbig
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alexander D Crawford
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Camila V Esguerra
- 30 Chemical Neuroscience Group, Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway 31 Laboratory for Molecular Biodiscovery, University of Leuven, Leuven, Belgium
| | | | - Bobby P C Koeleman
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | | | - Ingrid E Scheffer
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Sanjay M Sisodiya
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
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Noebels J. Pathway-driven discovery of epilepsy genes. Nat Neurosci 2015; 18:344-50. [PMID: 25710836 DOI: 10.1038/nn.3933] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/22/2014] [Indexed: 12/12/2022]
Abstract
Epilepsy genes deliver critical insights into the molecular control of brain synchronization and are revolutionizing our understanding and treatment of the disease. The epilepsy-associated genome is rapidly expanding, and two powerful complementary approaches, isolation of de novo exome variants in patients and targeted mutagenesis in model systems, account for the steep increase. In sheer number, the tally of genes linked to seizures will likely match that of cancer and exceed it in biological diversity. The proteins act within most intracellular compartments and span the molecular determinants of firing and wiring in the developing brain. Every facet of neurotransmission, from dendritic spine to exocytotic machinery, is in play, and defects of synaptic inhibition are over-represented. The contributions of somatic mutations and noncoding microRNAs are also being explored. The functional spectrum of established epilepsy genes and the arrival of rapid, precise technologies for genome editing now provide a robust scaffold to prioritize hypothesis-driven discovery and further populate this genetic proto-map. Although each gene identified offers translational potential to stratify patient care, the complexity of individual variation and covert actions of genetic modifiers may confound single-gene solutions for the clinical disorder. In vivo genetic deconstruction of epileptic networks, ex vivo validation of variant profiles in patient-derived induced pluripotent stem cells, in silico variant modeling and modifier gene discovery, now in their earliest stages, will help clarify individual patterns. Because seizures stand at the crossroads of all neuronal synchronization disorders in the developing and aging brain, the neurobiological analysis of epilepsy-associated genes provides an extraordinary gateway to new insights into higher cortical function.
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Affiliation(s)
- Jeffrey Noebels
- Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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Affected kindred analysis of human X chromosome exomes to identify novel X-linked intellectual disability genes. PLoS One 2015; 10:e0116454. [PMID: 25679214 PMCID: PMC4332666 DOI: 10.1371/journal.pone.0116454] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 12/08/2014] [Indexed: 12/30/2022] Open
Abstract
X-linked Intellectual Disability (XLID) is a group of genetically heterogeneous disorders caused by mutations in genes on the X chromosome. Deleterious mutations in ~10% of X chromosome genes are implicated in causing XLID disorders in ~50% of known and suspected XLID families. The remaining XLID genes are expected to be rare and even private to individual families. To systematically identify these XLID genes, we sequenced the X chromosome exome (X-exome) in 56 well-established XLID families (a single affected male from 30 families and two affected males from 26 families) using an Agilent SureSelect X-exome kit and the Illumina HiSeq 2000 platform. To enrich for disease-causing mutations, we first utilized variant filters based on dbSNP, the male-restricted portions of the 1000 Genomes Project, or the Exome Variant Server datasets. However, these databases present limitations as automatic filters for enrichment of XLID genes. We therefore developed and optimized a strategy that uses a cohort of affected male kindred pairs and an additional small cohort of affected unrelated males to enrich for potentially pathological variants and to remove neutral variants. This strategy, which we refer to as Affected Kindred/Cross-Cohort Analysis, achieves a substantial enrichment for potentially pathological variants in known XLID genes compared to variant filters from public reference databases, and it has identified novel XLID candidate genes. We conclude that Affected Kindred/Cross-Cohort Analysis can effectively enrich for disease-causing genes in rare, Mendelian disorders, and that public reference databases can be used effectively, but cautiously, as automatic filters for X-linked disorders.
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Berkovic SF, Jackson GD. 'Idiopathic' no more! Abnormal interaction of large-scale brain networks in generalized epilepsy. ACTA ACUST UNITED AC 2014; 137:2400-2. [PMID: 25125584 DOI: 10.1093/brain/awu194] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
| | - Graeme D Jackson
- The Florey Institute of Neuroscience and Mental Health, Australia
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