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Yuan B, Schulze KV, Assia Batzir N, Sinson J, Dai H, Zhu W, Bocanegra F, Fong CT, Holder J, Nguyen J, Schaaf CP, Yang Y, Bi W, Eng C, Shaw C, Lupski JR, Liu P. Sequencing individual genomes with recurrent genomic disorder deletions: an approach to characterize genes for autosomal recessive rare disease traits. Genome Med 2022; 14:113. [PMID: 36180924 PMCID: PMC9526336 DOI: 10.1186/s13073-022-01113-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 09/02/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND In medical genetics, discovery and characterization of disease trait contributory genes and alleles depends on genetic reasoning, study design, and patient ascertainment; we suggest a segmental haploid genetics approach to enhance gene discovery and molecular diagnostics. METHODS We constructed a genome-wide map for nonallelic homologous recombination (NAHR)-mediated recurrent genomic deletions and used this map to estimate population frequencies of NAHR deletions based on large-scale population cohorts and region-specific studies. We calculated recessive disease carrier burden using high-quality pathogenic or likely pathogenic variants from ClinVar and gnomAD. We developed a NIRD (NAHR deletion Impact to Recessive Disease) score for recessive disorders by quantifying the contribution of NAHR deletion to the overall allele load that enumerated all pairwise combinations of disease-causing alleles; we used a Punnett square approach based on an assumption of random mating. Literature mining was conducted to identify all reported patients with defects in a gene with a high NIRD score; meta-analysis was performed on these patients to estimate the representation of NAHR deletions in recessive traits from contemporary human genomics studies. Retrospective analyses of extant clinical exome sequencing (cES) were performed for novel rare recessive disease trait gene and allele discovery from individuals with NAHR deletions. RESULTS We present novel genomic insights regarding the genome-wide impact of NAHR recurrent segmental variants on recessive disease burden; we demonstrate the utility of NAHR recurrent deletions to enhance discovery in the challenging context of autosomal recessive (AR) traits and biallelic variation. Computational results demonstrate new mutations mediated by NAHR, involving recurrent deletions at 30 genomic regions, likely drive recessive disease burden for over 74% of loci within these segmental deletions or at least 2% of loci genome-wide. Meta-analyses on 170 literature-reported patients implicate that NAHR deletions are depleted from the ascertained pool of AR trait alleles. Exome reanalysis of personal genomes from subjects harboring recurrent deletions uncovered new disease-contributing variants in genes including COX10, ERCC6, PRRT2, and OTUD7A. CONCLUSIONS Our results demonstrate that genomic sequencing of personal genomes with NAHR deletions could dramatically improve allele and gene discovery and enhance clinical molecular diagnosis. Moreover, results suggest NAHR events could potentially enable human haploid genetic screens as an approach to experimental inquiry into disease biology.
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Affiliation(s)
- Bo Yuan
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
| | - Katharina V. Schulze
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Nurit Assia Batzir
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Jefferson Sinson
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Hongzheng Dai
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Wenmiao Zhu
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | | | - Chin-To Fong
- grid.412750.50000 0004 1936 9166Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Jimmy Holder
- grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA
| | - Joanne Nguyen
- grid.267308.80000 0000 9206 2401Department of Pediatrics, University of Texas Health Science Center, Houston, TX USA
| | - Christian P. Schaaf
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.7700.00000 0001 2190 4373Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Yaping Yang
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Weimin Bi
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Christine Eng
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Chad Shaw
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.21940.3e0000 0004 1936 8278Department of Statistics, Rice University, Houston, TX USA
| | - James R. Lupski
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Texas Children’s Hospital, Houston, TX USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Baylor Genetics, Houston, TX, USA.
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2
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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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3
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Budisteanu M, Papuc SM, Streata I, Cucu M, Pirvu A, Serban-Sosoi S, Erbescu A, Andrei E, Iliescu C, Ioana D, Severin E, Ioana M, Arghir A. The Phenotypic Spectrum of 15q13.3 Region Duplications: Report of 5 Patients. Genes (Basel) 2021; 12:1025. [PMID: 34356041 PMCID: PMC8306426 DOI: 10.3390/genes12071025] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 12/03/2022] Open
Abstract
Chromosome 15q13.3 microduplications are associated with a wide spectrum of clinical presentations ranging from normal to different neuropsychiatric conditions, such as developmental delay (DD), intellectual disability (ID), epilepsy, hypotonia, autism spectrum disorders (ASD), attention-deficit hyperactivity disorder, and schizophrenia. The smallest region of overlap for 15q13.3 duplications encompasses the Cholinergic Receptor Nicotinic Alpha 7 Subunit (CHRNA7) gene, a strong candidate for the behavioral abnormalities. We report on a series of five patients with 15q13.3 duplications detected by chromosomal microarray. The size of the duplications ranged from 378 to 537 kb, and involved the CHRNA7 gene in all patients. The most common clinical features, present in all patients, were speech delay, autistic behavior, and muscle hypotonia; DD/ID was present in three patients. One patient presented epileptic seizures; EEG anomalies were observed in three patients. No consistent dysmorphic features were noted. Neuroimaging studies revealed anomalies in two patients: Dandy-Walker malformation and a right temporal cyst. 15q13.3 duplications are associated with various neuropsychiatric features, including speech delay, hypotonia, ASD, and ID, also present in our patient group. Our study brings detailed clinical and molecular data from five ASD patients with 15q13.3 microduplications involving the CHRNA7 gene, contributing to the existing knowledge about the association of 15q13.3 duplications with neuropsychiatric phenotypes.
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Affiliation(s)
- Magdalena Budisteanu
- Department of Pediatric Neurology, Prof. Dr. Alex. Obregia Clinical Hospital of Psychiatry, 041914 Bucharest, Romania; (M.B.); (E.A.); (C.I.); (D.I.)
- Medical Genetics Laboratory, Victor Babes National Institute of Pathology, 050096 Bucharest, Romania; (A.E.); (A.A.)
- Department of Genetics, Faculty of Medicine, Titu Maiorescu University, 031593 Bucharest, Romania
| | - Sorina Mihaela Papuc
- Medical Genetics Laboratory, Victor Babes National Institute of Pathology, 050096 Bucharest, Romania; (A.E.); (A.A.)
| | - Ioana Streata
- Human Genomics Laboratory, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (I.S.); (M.C.); (A.P.); (S.S.-S.); (M.I.)
- Regional Center of Medical Genetics Dolj, 200642 Craiova, Romania
| | - Mihai Cucu
- Human Genomics Laboratory, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (I.S.); (M.C.); (A.P.); (S.S.-S.); (M.I.)
- Regional Center of Medical Genetics Dolj, 200642 Craiova, Romania
| | - Andrei Pirvu
- Human Genomics Laboratory, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (I.S.); (M.C.); (A.P.); (S.S.-S.); (M.I.)
- Regional Center of Medical Genetics Dolj, 200642 Craiova, Romania
| | - Simona Serban-Sosoi
- Human Genomics Laboratory, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (I.S.); (M.C.); (A.P.); (S.S.-S.); (M.I.)
- Regional Center of Medical Genetics Dolj, 200642 Craiova, Romania
| | - Alina Erbescu
- Medical Genetics Laboratory, Victor Babes National Institute of Pathology, 050096 Bucharest, Romania; (A.E.); (A.A.)
| | - Emanuela Andrei
- Department of Pediatric Neurology, Prof. Dr. Alex. Obregia Clinical Hospital of Psychiatry, 041914 Bucharest, Romania; (M.B.); (E.A.); (C.I.); (D.I.)
| | - Catrinel Iliescu
- Department of Pediatric Neurology, Prof. Dr. Alex. Obregia Clinical Hospital of Psychiatry, 041914 Bucharest, Romania; (M.B.); (E.A.); (C.I.); (D.I.)
| | - Doina Ioana
- Department of Pediatric Neurology, Prof. Dr. Alex. Obregia Clinical Hospital of Psychiatry, 041914 Bucharest, Romania; (M.B.); (E.A.); (C.I.); (D.I.)
| | - Emilia Severin
- Department of Genetics, Faculty of Dental Medicine, “Carol Davila” University of Medicine and Pharmacy Bucharest, 050474 Bucharest, Romania;
| | - Mihai Ioana
- Human Genomics Laboratory, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (I.S.); (M.C.); (A.P.); (S.S.-S.); (M.I.)
- Regional Center of Medical Genetics Dolj, 200642 Craiova, Romania
| | - Aurora Arghir
- Medical Genetics Laboratory, Victor Babes National Institute of Pathology, 050096 Bucharest, Romania; (A.E.); (A.A.)
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Heide M, Huttner WB. Human-Specific Genes, Cortical Progenitor Cells, and Microcephaly. Cells 2021; 10:1209. [PMID: 34063381 PMCID: PMC8156310 DOI: 10.3390/cells10051209] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/13/2022] Open
Abstract
Over the past few years, human-specific genes have received increasing attention as potential major contributors responsible for the 3-fold difference in brain size between human and chimpanzee. Accordingly, mutations affecting these genes may lead to a reduction in human brain size and therefore, may cause or contribute to microcephaly. In this review, we will concentrate, within the brain, on the cerebral cortex, the seat of our higher cognitive abilities, and focus on the human-specific gene ARHGAP11B and on the gene family comprising the three human-specific genes NOTCH2NLA, -B, and -C. These genes are thought to have significantly contributed to the expansion of the cerebral cortex during human evolution. We will summarize the evolution of these genes, as well as their expression and functional role during human cortical development, and discuss their potential relevance for microcephaly. Furthermore, we will give an overview of other human-specific genes that are expressed during fetal human cortical development. We will discuss the potential involvement of these genes in microcephaly and how these genes could be studied functionally to identify a possible role in microcephaly.
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Affiliation(s)
- Michael Heide
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstr. 108, D-01307 Dresden, Germany
| | - Wieland B. Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstr. 108, D-01307 Dresden, Germany
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5
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Suzuki H, Inaba M, Yamada M, Uehara T, Takenouchi T, Mizuno S, Kosaki K, Doi M. Biallelic loss of OTUD7A causes severe muscular hypotonia, intellectual disability, and seizures. Am J Med Genet A 2020; 185:1182-1186. [PMID: 33381903 DOI: 10.1002/ajmg.a.62054] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 02/02/2023]
Abstract
The heterozygous deletion of 15q13.3 is a recurrently observed microdeletion syndrome associated with a relatively mild phenotype including learning disability and language impairment. In contrast, the homozygous deletion of 15q13.3 is extremely rare and is associated with a much severer phenotype that includes epileptic encephalopathy, profound intellectual disability, and hypotonia. Which of the genes within the deleted interval is responsible for the more severe features when biallelically deleted is currently unknown. Here, we report a patient with profound hypotonia, severe intellectual disability, and seizures who had biallelic loss-of-function variants in OTUD7A: a 15q13.3 deletion including the OTUD7A locus, and a frameshift OTUD7A variant c.1125del, p.(Glu375Aspfs*11). Unexpectedly, both aberrations occurred de novo. Our experiment using Caenorhabditis elegans showed that worms carrying a corresponding homozygous variant in the homolog OTUB-2 exhibited weakened muscle contraction suggestive of aberrant neuromuscular transmission. We concluded that the biallelic complete loss of OTUD7A in humans represents a presumably new autosomal recessive disorder characterized by profound hypotonia, severe intellectual disability, and seizures.
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Affiliation(s)
- Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Mie Inaba
- Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Seiji Mizuno
- Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Motomichi Doi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
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6
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Hirose S, Tanaka Y, Shibata M, Kimura Y, Ishikawa M, Higurashi N, Yamamoto T, Ichise E, Chiyonobu T, Ishii A. Application of induced pluripotent stem cells in epilepsy. Mol Cell Neurosci 2020; 108:103535. [DOI: 10.1016/j.mcn.2020.103535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
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7
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Casamassa A, Ferrari D, Gelati M, Carella M, Vescovi AL, Rosati J. A Link between Genetic Disorders and Cellular Impairment, Using Human Induced Pluripotent Stem Cells to Reveal the Functional Consequences of Copy Number Variations in the Central Nervous System-A Close Look at Chromosome 15. Int J Mol Sci 2020; 21:ijms21051860. [PMID: 32182809 PMCID: PMC7084702 DOI: 10.3390/ijms21051860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/28/2022] Open
Abstract
Recent cutting-edge human genetics technology has allowed us to identify copy number variations (CNVs) and has provided new insights for understanding causative mechanisms of human diseases. A growing number of studies show that CNVs could be associated with physiological mechanisms linked to evolutionary trigger, as well as to the pathogenesis of various diseases, including cancer, autoimmune disease and mental disorders such as autism spectrum disorders, schizophrenia, intellectual disabilities or attention-deficit/hyperactivity disorder. Their incomplete penetrance and variable expressivity make diagnosis difficult and hinder comprehension of the mechanistic bases of these disorders. Additional elements such as co-presence of other CNVs, genomic background and environmental factors are involved in determining the final phenotype associated with a CNV. Genetically engineered animal models are helpful tools for understanding the behavioral consequences of CNVs. However, the genetic background and the biology of these animal model systems have sometimes led to confusing results. New cellular models obtained through somatic cellular reprogramming technology that produce induced pluripotent stem cells (iPSCs) from human subjects are being used to explore the mechanisms involved in the pathogenic consequences of CNVs. Considering the vast quantity of CNVs found in the human genome, we intend to focus on reviewing the current literature on the use of iPSCs carrying CNVs on chromosome 15, highlighting advantages and limits of this system with respect to mouse model systems.
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Affiliation(s)
- Alessia Casamassa
- Cellular Reprogramming Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy;
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, Viale Abramo Lincoln 5, 81100 Caserta, Italy
| | - Daniela Ferrari
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy;
| | - Maurizio Gelati
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
| | - Massimo Carella
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
| | - Angelo Luigi Vescovi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy;
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
- Correspondence: (A.L.V.); (J.R.)
| | - Jessica Rosati
- Cellular Reprogramming Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy;
- Correspondence: (A.L.V.); (J.R.)
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8
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Namba T, Dóczi J, Pinson A, Xing L, Kalebic N, Wilsch-Bräuninger M, Long KR, Vaid S, Lauer J, Bogdanova A, Borgonovo B, Shevchenko A, Keller P, Drechsel D, Kurzchalia T, Wimberger P, Chinopoulos C, Huttner WB. Human-Specific ARHGAP11B Acts in Mitochondria to Expand Neocortical Progenitors by Glutaminolysis. Neuron 2020; 105:867-881.e9. [PMID: 31883789 DOI: 10.1016/j.neuron.2019.11.027] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/28/2019] [Accepted: 11/25/2019] [Indexed: 12/17/2022]
Abstract
The human-specific gene ARHGAP11B is preferentially expressed in neural progenitors of fetal human neocortex and increases abundance and proliferation of basal progenitors (BPs), which have a key role in neocortex expansion. ARHGAP11B has therefore been implicated in the evolutionary expansion of the human neocortex, but its mode of action has been unknown. Here, we show that ARHGAP11B is imported into mitochondria, where it interacts with the adenine nucleotide translocase (ANT) and inhibits the mitochondrial permeability transition pore (mPTP). BP expansion by ARHGAP11B requires its presence in mitochondria, and pharmacological inhibition of ANT function or mPTP opening mimic BP expansion by ARHGAP11B. Searching for the underlying metabolic basis, we find that BP expansion by ARHGAP11B requires glutaminolysis, the conversion of glutamine to glutamate for the tricarboxylic acid (TCA) cycle. Hence, an ARHGAP11B-induced, mitochondria-based effect on BP metabolism that is a hallmark of highly mitotically active cells appears to underlie its role in neocortex expansion.
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Affiliation(s)
- Takashi Namba
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
| | - Judit Dóczi
- Department of Medical Biochemistry, Semmelweis University, Budapest, Tuzolto St. 37-47 1094, Hungary
| | - Anneline Pinson
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Lei Xing
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Nereo Kalebic
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Michaela Wilsch-Bräuninger
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Katherine R Long
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Samir Vaid
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Janelle Lauer
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Aliona Bogdanova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Barbara Borgonovo
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Anna Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Patrick Keller
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - David Drechsel
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Teymuras Kurzchalia
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Pauline Wimberger
- Universitätsklinikum Carl Gustav Carus, Klinik und Poliklinik für Frauenheilkunde und Geburtshilfe, Technische Universität Dresden, Dresden, Germany
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Tuzolto St. 37-47 1094, Hungary
| | - Wieland B Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
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9
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Garret P, Ebstein F, Delplancq G, Dozieres-Puyravel B, Boughalem A, Auvin S, Duffourd Y, Klafack S, Zieba BA, Mahmoudi S, Singh KK, Duplomb L, Thauvin-Robinet C, Costa JM, Krüger E, Trost D, Verloes A, Faivre L, Vitobello A. Report of the first patient with a homozygous OTUD7A variant responsible for epileptic encephalopathy and related proteasome dysfunction. Clin Genet 2020; 97:567-575. [PMID: 31997314 DOI: 10.1111/cge.13709] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 12/29/2022]
Abstract
Heterozygous microdeletions of chromosome 15q13.3 (MIM: 612001) show incomplete penetrance and are associated with a highly variable phenotype that may include intellectual disability, epilepsy, facial dysmorphism and digit anomalies. Rare patients carrying homozygous deletions show more severe phenotypes including epileptic encephalopathy, hypotonia and poor growth. For years, CHRNA7 (MIM: 118511), was considered the candidate gene that could account for this syndrome. However, recent studies in mouse models have shown that OTUD7A/CEZANNE2 (MIM: 612024), which encodes for an ovarian tumor (OTU) deubiquitinase, should be considered the critical gene responsible for brain dysfunction. In this study, a patient presenting with severe global developmental delay, language impairment and epileptic encephalopathy was referred to our genetics center. Trio exome sequencing (tES) analysis identified a homozygous OTUD7A missense variant (NM_130901.2:c.697C>T), predicted to alter an ultraconserved amino acid, p.(Leu233Phe), lying within the OTU catalytic domain. Its subsequent segregation analysis revealed that the parents, presenting with learning disability, and brother were heterozygous carriers. Biochemical assays demonstrated that proteasome complex formation and function were significantly reduced in patient-derived fibroblasts and in OTUD7A knockout HAP1 cell line. We provide evidence that biallelic pathogenic OTUD7A variation is linked to early-onset epileptic encephalopathy and proteasome dysfunction.
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Affiliation(s)
- Philippine Garret
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Laboratoire CERBA, Saint-Ouen l'Aumône, France
| | - Frédéric Ebstein
- Universitätsmedizin Greifswald, Institut für Medizinische Biochemie und Molekularbiologie, Greifswald, Germany
| | - Geoffroy Delplancq
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | | | | | - Stéphane Auvin
- AP-HP, Hôpital Robert Debré, Service de Neurologie pédiatrique, Paris, France.,UMR1141 INSERM, Université Paris Diderot, Paris, France
| | - Yannis Duffourd
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Sandro Klafack
- Universitätsmedizin Greifswald, Institut für Medizinische Biochemie und Molekularbiologie, Greifswald, Germany
| | - Barbara A Zieba
- Universitätsmedizin Greifswald, Institut für Medizinische Biochemie und Molekularbiologie, Greifswald, Germany
| | - Sana Mahmoudi
- Service de Pédiatrie, Centre Hospitalier René-Dubos, Pontoise, France
| | - Karun K Singh
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, Canada
| | - Laurence Duplomb
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Christel Thauvin-Robinet
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France.,Centre de Référence Maladies Rares "déficience intellectuelle", centre de génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | | | - Elke Krüger
- Universitätsmedizin Greifswald, Institut für Medizinische Biochemie und Molekularbiologie, Greifswald, Germany
| | | | - Alain Verloes
- UMR1141 INSERM, Université Paris Diderot, Paris, France.,Genetics Department, AP-HP, Robert-Debré University Hospital, Paris, France
| | - Laurence Faivre
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Centre de Référence Maladies Rares "Anomalies du développement et syndromes malformatifs", centre de génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Antonio Vitobello
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
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10
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Pavone P, Ruggieri M, Marino SD, Corsello G, Pappalardo X, Polizzi A, Parano E, Romano C, Marino S, Praticò AD, Falsaperla R. Chromosome 15q BP3 to BP5 deletion is a likely locus for speech delay and language impairment: Report on a four-member family and an unrelated boy. Mol Genet Genomic Med 2020; 8:e1109. [PMID: 31991071 PMCID: PMC7196468 DOI: 10.1002/mgg3.1109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 01/13/2023] Open
Abstract
Background Deletions in chromosome 15q13 have been reported both in healthy people and individuals with a wide range of behavioral and neuropsychiatric disturbances. Six main breakpoint (BP) subregions (BP1‐BP6) are mapped to the 15q13 region and three further embedded BP regions (BP3‐BP5). The deletion at BP4‐BP5 is the rearrangement most frequently observed compared to other known deletions in BP3‐BP5 and BP3‐BP4 regions. Deletions of each of these three regions have previously been implicated in a variable range of clinical phenotypes, including minor dysmorphism, developmental delay/intellectual disability, epilepsy, autism spectrum disorders, behavioral disturbances, and speech disorders. Of note, no overt clinical difference among each group of BP region deletions has been recorded so far. Methods We report on a four‐member family plus an additional unrelated boy affected by a BP3‐BP5 deletion that presented with typical clinical signs including speech delay and language impairment. A review of the clinical features associated with the three main groups of BP regions (BP4‐BP5, BP3‐BP5, and BP3‐BP4) deletions is reported. Results Array‐CGH analysis revealed in the mother (case 1) and in her three children (cases 2, 3, and 4), as well as in the unrelated boy (case 5), the following rearrangement: arr (hg19) 15q13.1‐q13.3 (29.213.402–32.510.863) x1. Conclusion This report, along with other recent observations, suggests the hypothesis that the BP region comprised between BP3 and BP5 in chromosome 15q13 is involved in several brain human dysfunctions, including impairment of the language development and, its deletion, may be directly or indirectly responsible for the speech delay and language deficit in the affected individuals.
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Affiliation(s)
- Piero Pavone
- Unit of Clinical Pediatrics, University Hospital "Policlinico-Vittorio Emanuele", University of Catania, Catania, Italy.,Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Martino Ruggieri
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Simona D Marino
- Units of Pediatrics and Pediatric Emergency, University Hospital "Policlinico-Vittorio Emanuele", Catania, Italy
| | - Giovanni Corsello
- Units of Pediatrics and Neonatal Intensive Care, Department of Health Promotion of Maternal-Infantile Care and of Excellence Internal and Specialist Medicine "G. D'Alessandro" [PROMISE], University of Palermo, Palermo, Italy
| | - Xena Pappalardo
- National Council of Research, Institute for Research and Biomedical Innovation (IRIB), Unit of Catania, Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Enrico Parano
- National Council of Research, Institute for Research and Biomedical Innovation (IRIB), Unit of Catania, Catania, Italy
| | - Catia Romano
- Units of Pediatrics and Pediatric Emergency, University Hospital "Policlinico-Vittorio Emanuele", Catania, Italy
| | - Silvia Marino
- Units of Pediatrics and Pediatric Emergency, University Hospital "Policlinico-Vittorio Emanuele", Catania, Italy
| | - Andrea Domenico Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Units of Pediatrics and Pediatric Emergency, University Hospital "Policlinico-Vittorio Emanuele", Catania, Italy
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11
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Simon J, Stoll K, Fick R, Mott J, Lawson‐Yuen A. Homozygous 15q13.3 microdeletion in a child with hypotonia and impaired vision: A new report and review of the literature. Clin Case Rep 2019; 7:2311-2315. [PMID: 31893048 PMCID: PMC6935653 DOI: 10.1002/ccr3.2403] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/11/2019] [Accepted: 07/29/2019] [Indexed: 11/08/2022] Open
Abstract
Although there are numerous reports of heterozygous 15q13.3 microdeletion, homozygous 15q13.3 microdeletion is rare. We report a new patient with homozygous microdeletion of 15q13.2q13.3 and review the previous literature reports. Common clinical features include encephalopathy, hypotonia, developmental delay, cortical vision impairment, optic nerve abnormality, epilepsy, and abnormal electroencephalogram (EEG) findings.
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Affiliation(s)
| | | | - Roger Fick
- Genomics InstituteMary Bridge Children's Hospital, MultiCare Health SystemTacomaWashington
| | - Jared Mott
- Department of Pediatric NeurologyMary Bridge Children's Hospital, MultiCare Health SystemTacomaWashington
| | - Amy Lawson‐Yuen
- Genomics InstituteMary Bridge Children's Hospital, MultiCare Health SystemTacomaWashington
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12
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Alsagob M, Salih MA, Hamad MHA, Al-Yafee Y, Al-Zahrani J, Al-Bakheet A, Nester M, Sakati N, Wakil SM, AlOdaib A, Colak D, Kaya N. First report of two successive deletions on chromosome 15q13 cytogenetic bands in a boy and girl: additional data to 15q13.3 syndrome with a report of high IQ patient. Mol Cytogenet 2019; 12:21. [PMID: 31131027 PMCID: PMC6525444 DOI: 10.1186/s13039-019-0432-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/01/2019] [Indexed: 11/10/2022] Open
Abstract
15q13.3 syndrome is associated with a wide spectrum of neurological disorders. Among a cohort of 150 neurodevelopmental cases, we identified two patients with two close proximity interstitial hemizygous deletions on chromosome 15q13. Using high-density microarrays, we characterized these deletions and their approximate breakpoints. The second deletion in both patients overlaps in a small area containing CHRNA7 where the gene is partially deleted. The CHRNA7 is considered a strong candidate for the 15q13.3 deletion syndrome's pathogenicity. Patient 1 has cognitive impairment, learning disabilities, hyperactivity and subtle dysmorphic features whereas patient 2 has mild language impairment with speech difficulty, mild dysmorphia, heart defect and interestingly a high IQ that has not been reported in 15q13.3 syndrome patients before. Our study presents first report of such two successive deletions in 15q13.3 syndrome patients and a high IQ in a 15q13.3 syndrome patient. Our study expands the breakpoints and phenotypic features related to 15q13.3 syndrome.
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Affiliation(s)
- Maysoon Alsagob
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Mustafa A Salih
- 2Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Muddathir H A Hamad
- 2Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Yusra Al-Yafee
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Jawaher Al-Zahrani
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Albandary Al-Bakheet
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Michael Nester
- 3Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Nadia Sakati
- 3Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Salma M Wakil
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Ali AlOdaib
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia
| | - Dilek Colak
- 4Department of Biostatistics, Epidemiology, and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Namik Kaya
- 1Department of Genetics, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, 11211 Kingdom of Saudi Arabia.,2Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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13
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Calhoun JD, Carvill GL. Unravelling the genetic architecture of autosomal recessive epilepsy in the genomic era. J Neurogenet 2018; 32:295-312. [PMID: 30247086 DOI: 10.1080/01677063.2018.1513509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The technological advancement of next-generation sequencing has greatly accelerated the pace of variant discovery in epilepsy. Despite an initial focus on autosomal dominant epilepsy due to the tractable nature of variant discovery with trios under a de novo model, more and more variants are being reported in families with epilepsies consistent with autosomal recessive (AR) inheritance. In this review, we touch on the classical AR epilepsy variants such as the inborn errors of metabolism and malformations of cortical development. However, we also highlight recently reported genes that are being identified by next-generation sequencing approaches and online 'matchmaking' platforms. Syndromes mainly characterized by seizures and complex neurodevelopmental disorders comorbid with epilepsy are discussed as an example of the wide phenotypic spectrum associated with the AR epilepsies. We conclude with a foray into the future, from the application of whole-genome sequencing to identify elusive epilepsy variants, to the promise of precision medicine initiatives to provide novel targeted therapeutics specific to the individual based on their clinical genetic testing.
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Affiliation(s)
- Jeffrey D Calhoun
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
| | - Gemma L Carvill
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
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14
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Yin J, Chen W, Chao ES, Soriano S, Wang L, Wang W, Cummock SE, Tao H, Pang K, Liu Z, Pereira FA, Samaco RC, Zoghbi HY, Xue M, Schaaf CP. Otud7a Knockout Mice Recapitulate Many Neurological Features of 15q13.3 Microdeletion Syndrome. Am J Hum Genet 2018; 102:296-308. [PMID: 29395075 DOI: 10.1016/j.ajhg.2018.01.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/10/2018] [Indexed: 10/18/2022] Open
Abstract
15q13.3 microdeletion syndrome is characterized by a wide spectrum of neurodevelopmental disorders, including developmental delay, intellectual disability, epilepsy, language impairment, abnormal behaviors, neuropsychiatric disorders, and hypotonia. This syndrome is caused by a deletion on chromosome 15q, which typically encompasses six genes. Here, through studies on OTU deubiquitinase 7A (Otud7a) knockout mice, we identify OTUD7A as a critical gene responsible for many of the cardinal phenotypes associated with 15q13.3 microdeletion syndrome. Otud7a-null mice show reduced body weight, developmental delay, abnormal electroencephalography patterns and seizures, reduced ultrasonic vocalizations, decreased grip strength, impaired motor learning/motor coordination, and reduced acoustic startle. We show that OTUD7A localizes to dendritic spines and that Otud7a-null mice have decreased dendritic spine density compared to their wild-type littermates. Furthermore, frequency of miniature excitatory postsynaptic currents (mEPSCs) is reduced in the frontal cortex of Otud7a-null mice, suggesting a role of Otud7a in regulation of dendritic spine density and glutamatergic synaptic transmission. Taken together, our results suggest decreased OTUD7A dosage as a major contributor to the neurodevelopmental phenotypes associated with 15q13.3 microdeletion syndrome, through the misregulation of dendritic spine density and activity.
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15
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Dynamic changes in murine forebrain miR-211 expression associate with cholinergic imbalances and epileptiform activity. Proc Natl Acad Sci U S A 2017; 114:E4996-E5005. [PMID: 28584127 DOI: 10.1073/pnas.1701201114] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Epilepsy is a common neurological disease, manifested in unprovoked recurrent seizures. Epileptogenesis may develop due to genetic or pharmacological origins or following injury, but it remains unclear how the unaffected brain escapes this susceptibility to seizures. Here, we report that dynamic changes in forebrain microRNA (miR)-211 in the mouse brain shift the threshold for spontaneous and pharmacologically induced seizures alongside changes in the cholinergic pathway genes, implicating this miR in the avoidance of seizures. We identified miR-211 as a putative attenuator of cholinergic-mediated seizures by intersecting forebrain miR profiles that were Argonaute precipitated, synaptic vesicle target enriched, or differentially expressed under pilocarpine-induced seizures, and validated TGFBR2 and the nicotinic antiinflammatory acetylcholine receptor nAChRa7 as murine and human miR-211 targets, respectively. To explore the link between miR-211 and epilepsy, we engineered dTg-211 mice with doxycycline-suppressible forebrain overexpression of miR-211. These mice reacted to doxycycline exposure by spontaneous electrocorticography-documented nonconvulsive seizures, accompanied by forebrain accumulation of the convulsive seizures mediating miR-134. RNA sequencing demonstrated in doxycycline-treated dTg-211 cortices overrepresentation of synaptic activity, Ca2+ transmembrane transport, TGFBR2 signaling, and cholinergic synapse pathways. Additionally, a cholinergic dysregulated mouse model overexpressing a miR refractory acetylcholinesterase-R splice variant showed a parallel propensity for convulsions, miR-211 decreases, and miR-134 elevation. Our findings demonstrate that in mice, dynamic miR-211 decreases induce hypersynchronization and nonconvulsive and convulsive seizures, accompanied by expression changes in cholinergic and TGFBR2 pathways as well as in miR-134. Realizing the importance of miR-211 dynamics opens new venues for translational diagnosis of and interference with epilepsy.
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16
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Ehmke N, Karge S, Buchmann J, Korinth D, Horn D, Reis O, Häßler F. A de novo nonsense mutation in ZBTB18 plus a de novo 15q13.3 microdeletion in a 6-year-old female. Am J Med Genet A 2017; 173:1251-1256. [PMID: 28345786 DOI: 10.1002/ajmg.a.38145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 12/11/2022]
Abstract
ZBTB18 has been proposed as candidate gene for microcephaly and abnormalities of the corpus callosum based on overlapping microdeletions of 1q43q44. More recently, de novo mutations of ZBTB18 have been identified in patients with syndromic and non-syndromic intellectual disability. Heterozygous microdeletions of 15q13.3 encompassing the candidate gene CHRNA7 are associated with developmental delay or intellectual disability with speech problems, hypotonia, and seizures. They are characterized by significant variability and reduced penetrance. We report on a patient with a de novo ZBTB18 nonsense mutation and a de novo 15q13.3 microdeletion, both in a heterozygous state, identified by next generation sequencing and array-CGH. The 6-year-old girl showed global developmental delay, absent speech, therapy-refractory seizures, ataxia, muscular hypotonia, and discrete facial dysmorphisms. Almost all of these features have been reported for both genetic aberrations, but the severity could hardly been explained by the microdeletion 15q13.3 alone. We assume an additive effect of haploinsufficiency of ZBTB18 and CHRNA7 in our patient. Assembling the features of our patient and the published patients, we noted that only one of them showed mild anomalies of the corpus callosum. Moreover, we hypothesize that nonsense mutations of ZBTB18 are associated with a more severe phenotype than missense mutations. This report indicates that haploinsufficiency of additional genes beside ZBTB18 causes the high frequency of corpus callosum anomalies in patients with microdeletions of 1q43q44 and underlines the importance of an NGS-based molecular diagnostic in complex phenotypes.
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Affiliation(s)
- Nadja Ehmke
- Institute of Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Sylvio Karge
- Clinics for Child and Adolescent Psychiatry of the University of Rostock, Rostock, Germany
| | - Johannes Buchmann
- Clinics for Child and Adolescent Psychiatry of the University of Rostock, Rostock, Germany
| | | | - Denise Horn
- Institute of Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Olaf Reis
- Clinics for Child and Adolescent Psychiatry of the University of Rostock, Rostock, Germany
| | - Frank Häßler
- Clinics for Child and Adolescent Psychiatry of the University of Rostock, Rostock, Germany
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17
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Iha HA, Kunisawa N, Shimizu S, Tokudome K, Mukai T, Kinboshi M, Ikeda A, Ito H, Serikawa T, Ohno Y. Nicotine Elicits Convulsive Seizures by Activating Amygdalar Neurons. Front Pharmacol 2017; 8:57. [PMID: 28232801 PMCID: PMC5298991 DOI: 10.3389/fphar.2017.00057] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 01/26/2017] [Indexed: 12/14/2022] Open
Abstract
Nicotinic acetylcholine (nACh) receptors are implicated in the pathogenesis of epileptic disorders; however, the mechanisms of nACh receptors in seizure generation remain unknown. Here, we performed behavioral and immunohistochemical studies in mice and rats to clarify the mechanisms underlying nicotine-induced seizures. Treatment of animals with nicotine (1–4 mg/kg, i.p.) produced motor excitement in a dose-dependent manner and elicited convulsive seizures at 3 and 4 mg/kg. The nicotine-induced seizures were abolished by a subtype non-selective nACh antagonist, mecamylamine (MEC). An α7 nACh antagonist, methyllycaconitine, also significantly inhibited nicotine-induced seizures whereas an α4β2 nACh antagonist, dihydro-β-erythroidine, affected only weakly. Topographical analysis of Fos protein expression, a biological marker of neural excitation, revealed that a convulsive dose (4 mg/kg) of nicotine region-specifically activated neurons in the piriform cortex, amygdala, medial habenula, paratenial thalamus, anterior hypothalamus and solitary nucleus among 48 brain regions examined, and this was also suppressed by MEC. In addition, electric lesioning of the amygdala, but not the piriform cortex, medial habenula and thalamus, specifically inhibited nicotine-induced seizures. Furthermore, microinjection of nicotine (100 and 300 μg/side) into the amygdala elicited convulsive seizures in a dose-related manner. The present results suggest that nicotine elicits convulsive seizures by activating amygdalar neurons mainly via α7 nACh receptors.
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Affiliation(s)
- Higor A Iha
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Naofumi Kunisawa
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Saki Shimizu
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Kentaro Tokudome
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Takahiro Mukai
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Masato Kinboshi
- Laboratory of Pharmacology, Osaka University of Pharmaceutical SciencesOsaka, Japan; Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto UniversityKyoto, Japan; Department of Neurology, Graduate School of Medicine, Wakayama Medical UniversityWakayama, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Hidefumi Ito
- Department of Neurology, Graduate School of Medicine, Wakayama Medical University Wakayama, Japan
| | - Tadao Serikawa
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | - Yukihiro Ohno
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
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18
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Chrna7 deficient mice manifest no consistent neuropsychiatric and behavioral phenotypes. Sci Rep 2017; 7:39941. [PMID: 28045139 PMCID: PMC5206704 DOI: 10.1038/srep39941] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/28/2016] [Indexed: 11/22/2022] Open
Abstract
The alpha7 nicotinic acetylcholine receptor, encoded by the CHRNA7 gene, has been implicated in various psychiatric and behavioral disorders, including schizophrenia, bipolar disorder, epilepsy, autism, Alzheimer’s disease, and Parkinson’s disease, and is considered a potential target for therapeutic intervention. 15q13.3 microdeletion syndrome is a rare genetic disorder, caused by submicroscopic deletions on chromosome 15q. CHRNA7 is the only gene in this locus that has been deleted entirely in cases involving the smallest microdeletions. Affected individuals manifest variable neurological and behavioral phenotypes, which commonly include developmental delay/intellectual disability, epilepsy, and autism spectrum disorder. Subsets of patients have short attention spans, aggressive behaviors, mood disorders, or schizophrenia. Previous behavioral studies suggested that Chrna7 deficient mice had attention deficits, but were normal in baseline behavioral responses, learning, memory, and sensorimotor gating. Given a growing interest in CHRNA7-related diseases and a better appreciation of its associated human phenotypes, an in-depth behavioral characterization of the Chrna7 deficient mouse model appeared prudent. This study was designed to investigate whether Chrna7 deficient mice manifest phenotypes related to those seen in human individuals, using an array of 12 behavioral assessments and electroencephalogram (EEG) recordings on freely-moving mice. Examined phenotypes included social interaction, compulsive behaviors, aggression, hyperactivity, anxiety, depression, and somatosensory gating. Our data suggests that mouse behavior and EEG recordings are not sensitive to decreased Chrna7 copy number.
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19
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Kunisawa N, Iha HA, Shimizu S, Tokudome K, Mukai T, Kinboshi M, Serikawa T, Ohno Y. Nicotine evokes kinetic tremor by activating the inferior olive via α7 nicotinic acetylcholine receptors. Behav Brain Res 2016; 314:173-80. [DOI: 10.1016/j.bbr.2016.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/02/2016] [Accepted: 08/06/2016] [Indexed: 10/21/2022]
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20
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John D, Berg DK. Long-lasting changes in neural networks to compensate for altered nicotinic input. Biochem Pharmacol 2015; 97:418-424. [PMID: 26206188 PMCID: PMC4600434 DOI: 10.1016/j.bcp.2015.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 07/07/2015] [Indexed: 11/21/2022]
Abstract
The nervous system must balance excitatory and inhibitory input to constrain network activity levels within a proper dynamic range. This is a demanding requirement during development, when networks form and throughout adulthood as networks respond to constantly changing environments. Defects in the ability to sustain a proper balance of excitatory and inhibitory activity are characteristic of numerous neurological disorders such as schizophrenia, Alzheimer's disease, and autism. A variety of homeostatic mechanisms appear to be critical for balancing excitatory and inhibitory activity in a network. These are operative at the level of individual neurons, regulating their excitability by adjusting the numbers and types of ion channels, and at the level of synaptic connections, determining the relative numbers of excitatory versus inhibitory connections a neuron receives. Nicotinic cholinergic signaling is well positioned to contribute at both levels because it appears early in development, extends across much of the nervous system, and modulates transmission at many kinds of synapses. Further, it is known to influence the ratio of excitatory-to-inhibitory synapses formed on neurons during development. GABAergic inhibitory neurons are likely to be key for maintaining network homeostasis (limiting excitatory output), and nicotinic signaling is known to prominently regulate the activity of several GABAergic neuronal subtypes. But how nicotinic signaling achieves this and how networks may compensate for the loss of such input are important questions remaining unanswered. These issues are reviewed.
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Affiliation(s)
- Danielle John
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0357, United States; Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093-0357, United States
| | - Darwin K Berg
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0357, United States; Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093-0357, United States.
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Gonsales MC, Montenegro MA, Soler CV, Coan AC, Guerreiro MM, Lopes-Cendes I. Recent developments in the genetics of childhood epileptic encephalopathies: impact in clinical practice. ARQUIVOS DE NEURO-PSIQUIATRIA 2015; 73:946-58. [PMID: 26517219 DOI: 10.1590/0004-282x20150122] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/20/2015] [Indexed: 01/03/2023]
Abstract
Recent advances in molecular genetics led to the discovery of several genes for childhood epileptic encephalopathies (CEEs). As the knowledge about the genes associated with this group of disorders develops, it becomes evident that CEEs present a number of specific genetic characteristics, which will influence the use of molecular testing for clinical purposes. Among these, there are the presence of marked genetic heterogeneity and the high frequency of de novo mutations. Therefore, the main objectives of this review paper are to present and discuss current knowledge regarding i) new genetic findings in CEEs, ii) phenotype-genotype correlations in different forms of CEEs; and, most importantly, iii) the impact of these new findings in clinical practice. Accompanying this text we have included a comprehensive table, containing the list of genes currently known to be involved in the etiology of CEEs.
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Affiliation(s)
- Marina C Gonsales
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Maria Augusta Montenegro
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Camila V Soler
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Ana Carolina Coan
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Marilisa M Guerreiro
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Iscia Lopes-Cendes
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
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Copy Number Variation Screen Identifies a Rare De Novo Deletion at Chromosome 15q13.1-13.3 in a Child with Language Impairment. PLoS One 2015; 10:e0134997. [PMID: 26262844 PMCID: PMC4532445 DOI: 10.1371/journal.pone.0134997] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/17/2015] [Indexed: 01/15/2023] Open
Abstract
A significant proportion of children (up to 7% in the UK) present with pronounced language difficulties that cannot be explained by obvious causes like other neurological and medical conditions. A substantial genetic component is predicted to underlie such language problems. Copy number variants (CNVs) have been implicated in neurodevelopmental and psychiatric conditions, such as autism and schizophrenia, but it is not fully established to what extent they might contribute to language disorders. We conducted a CNV screen in a longitudinal cohort of young children with language-related difficulties (n = 85), focusing on single events at candidate loci. We detected a de novo deletion on chromosome 15q13.1–13.3. The adjacent 15q11-13.1 locus is disrupted in Prader-Willi and Angelman syndromes, while disruptions across the breakpoints (BP1-BP6) have previously been implicated in different neurodevelopmental phenotypes including autism, intellectual disability (ID), seizures and developmental delay (DD). This is the first report of a deletion at BP3-BP5 being linked to a deficit confined to language impairment, in the absence of ID, expanding the range of phenotypes that implicate the chromosome 15q13 locus.
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Gillentine MA, Schaaf CP. The human clinical phenotypes of altered CHRNA7 copy number. Biochem Pharmacol 2015; 97:352-362. [PMID: 26095975 DOI: 10.1016/j.bcp.2015.06.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 06/10/2015] [Indexed: 01/03/2023]
Abstract
Copy number variants (CNVs) have been implicated in multiple neuropsychiatric conditions, including autism spectrum disorder (ASD), schizophrenia, and intellectual disability (ID). Chromosome 15q13 is a hotspot for such CNVs due to the presence of low copy repeat (LCR) elements, which facilitate non-allelic homologous recombination (NAHR). Several of these CNVs have been overrepresented in individuals with neuropsychiatric disorders; yet variable expressivity and incomplete penetrance are commonly seen. Dosage sensitivity of the CHRNA7 gene, which encodes for the α7 nicotinic acetylcholine receptor in the human brain, has been proposed to have a major contribution to the observed cognitive and behavioral phenotypes, as it represents the smallest region of overlap to all the 15q13.3 deletions and duplications. Individuals with zero to four copies of CHRNA7 have been reported in the literature, and represent a range of clinical severity, with deletions causing generally more severe and more highly penetrant phenotypes. Potential mechanisms to account for the variable expressivity within each group of 15q13.3 CNVs will be discussed.
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Affiliation(s)
- Madelyn A Gillentine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Christian P Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States.
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Lin H, Hsu FC, Baumann BH, Coulter DA, Anderson SA, Lynch DR. Cortical parvalbumin GABAergic deficits with α7 nicotinic acetylcholine receptor deletion: implications for schizophrenia. Mol Cell Neurosci 2014; 61:163-75. [PMID: 24983521 DOI: 10.1016/j.mcn.2014.06.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/23/2014] [Accepted: 06/16/2014] [Indexed: 11/25/2022] Open
Abstract
Dysfunction of cortical parvalbumin (PV)-containing GABAergic interneurons has been implicated in cognitive deficits of schizophrenia. In humans microdeletion of the CHRNA7 (α7 nicotinic acetylcholine receptor, nAChR) gene is associated with cortical dysfunction in a broad spectrum of neurodevelopmental and neuropsychiatric disorders including schizophrenia while in mice similar deletion causes analogous abnormalities including impaired attention, working-memory and learning. However, the pathophysiological roles of α7 nAChRs in cortical PV GABAergic development remain largely uncharacterized. In both in vivo and in vitro models, we identify here that deletion of the α7 nAChR gene in mice impairs cortical PV GABAergic development and recapitulates many of the characteristic neurochemical deficits in PV-positive GABAergic interneurons found in schizophrenia. α7 nAChR null mice had decreased cortical levels of GABAergic markers including PV, glutamic acid decarboxylase 65/67 (GAD65/67) and the α1 subunit of GABAA receptors, particularly reductions of PV and GAD67 levels in cortical PV-positive interneurons during late postnatal life and adulthood. Cortical GABAergic synaptic deficits were identified in the prefrontal cortex of α7 nAChR null mice and α7 nAChR null cortical cultures. Similar disruptions in development of PV-positive GABAergic interneurons and perisomatic synapses were found in cortical cultures lacking α7 nAChRs. Moreover, NMDA receptor expression was reduced in GABAergic interneurons, implicating NMDA receptor hypofunction in GABAergic deficits in α7 nAChR null mice. Our findings thus demonstrate impaired cortical PV GABAergic development and multiple characteristic neurochemical deficits reminiscent of schizophrenia in cortical PV-positive interneurons in α7 nAChR gene deletion models. This implicates crucial roles of α7 nAChRs in cortical PV GABAergic development and dysfunction in schizophrenia and other neuropsychiatric disorders.
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Affiliation(s)
- Hong Lin
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Fu-Chun Hsu
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Bailey H Baumann
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Douglas A Coulter
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Stewart A Anderson
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Child Psychiatry, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - David R Lynch
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
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Clinical utility gene card for: 15q13.3 microdeletion syndrome. Eur J Hum Genet 2014; 22:ejhg201488. [PMID: 24824131 DOI: 10.1038/ejhg.2014.88] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/04/2014] [Accepted: 04/09/2014] [Indexed: 12/20/2022] Open
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Prasun P, Hankerd M, Kristofice M, Scussel L, Sivaswamy L, Ebrahim S. Compound heterozygous microdeletion of chromosome 15q13.3 region in a child with hypotonia, impaired vision, and global developmental delay. Am J Med Genet A 2014; 164A:1815-20. [PMID: 24700535 DOI: 10.1002/ajmg.a.36535] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 02/16/2014] [Indexed: 11/06/2022]
Abstract
Homozygous or compound heterozygous microdeletion of 15q13.3 region is a rare but clinically recognizable syndrome manifested by profound intellectual disability, muscular hypotonia, intractable seizures, and visual impairment. We identified a compound heterozygous 15q13.3 microdeletion in a 23-month-old girl with global developmental delay, generalized muscular hypotonia, and visual dysfunction. The larger deletion was approximately 1.28 Mb in size and contained seven genes including the TRPM1 and CHRNA7, while the smaller deletion was estimated to be 410 Kb in size and contained only CHRNA7. Compound heterozygous 15q13.3 microdeletion is extremely rare and to the best of our knowledge only two such patients have been reported in literature thus far. The findings in our patient suggest that the pathogenesis of visual dysfunction, which is a consistent finding in homozygous/compound heterozygous 15q13.3 microdeletion depends upon the size of microdeletion. Homozygous loss of TRPM1 likely causes retinal dysfunction while homozygous loss of CHRNA7 alone may lead to visual impairment by cortical mechanisms.
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Affiliation(s)
- Pankaj Prasun
- Division of Genetics & Metabolic Disorders, Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan
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27
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Masurel-Paulet A, Drumare I, Holder M, Cuisset JM, Vallée L, Defoort S, Bourgois B, Pernes P, Cuvellier JC, Huet F, Chehadeh SE, Thevenon J, Callier P, Thauvin C, Faivre L, Andrieux J. Further delineation of eye manifestations in homozygous 15q13.3 microdeletions including TRPM1: a differential diagnosis of ceroid lipofuscinosis. Am J Med Genet A 2014; 164A:1537-44. [PMID: 24668847 DOI: 10.1002/ajmg.a.36471] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 12/31/2013] [Indexed: 11/11/2022]
Abstract
The 15q13.3 heterozygous microdeletion is a fairly common microdeletion syndrome with marked clinical variability and incomplete penetrance. The average size of the deletion, which comprises six genes including CHRNA7, is 1.5 Mb. CHRNA7 has been identified as the gene responsible for the neurological phenotype in this microdeletion syndrome. Only seven patients with a homozygous microdeletion that includes at least CHRNA7, and is inherited from both parents have been described in the literature. The aim of this study was to further describe the distinctive eye manifestations from the analysis in the three French patients diagnosed with the classical 1.5 Mb homozygous microdeletion. Patients' ages ranged from 30 months to 9 years, and included one sib pair. They all displayed a remarkably severe identifiable clinical phenotype that included congenital blindness and convulsive encephalopathy with inconstant abnormal movements. The ophthalmological examination revealed a lack of eye tracking, optic nerve pallor, an immature response with increased latencies with no response to the checkerboard stimulations at the visual evoked potential examination, and a distinctive retina dystrophy with a negative electroretinogram in which the "b" wave was smaller than the "a" wave after a dark adapted pupil and bright flash in all patients. Clear genotype-phenotype correlations emerged, showing that this eye phenotype was secondary to homozygous deletion of TRPM1, the gene responsible for autosomal recessive congenital stationary night blindness. The main differential diagnosis is ceroid lipofuscinosis.
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Affiliation(s)
- Alice Masurel-Paulet
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, CHU Dijon, France
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28
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Schaaf CP. Nicotinic acetylcholine receptors in human genetic disease. Genet Med 2014; 16:649-56. [DOI: 10.1038/gim.2014.9] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023] Open
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Abstract
Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a "risk" allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are currently not fulfilled for common genomic variants in psychiatric disorders. Further work is clearly needed before genetic testing for common variants in psychiatric disorders should be established.
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Affiliation(s)
- Berit Kerner
- Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA
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30
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Cortical synaptic NMDA receptor deficits in α7 nicotinic acetylcholine receptor gene deletion models: implications for neuropsychiatric diseases. Neurobiol Dis 2013; 63:129-40. [PMID: 24326163 DOI: 10.1016/j.nbd.2013.11.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 01/06/2023] Open
Abstract
Microdeletion of the human CHRNA7 gene (α7 nicotinic acetylcholine receptor, nAChR) as well as dysfunction in N-methyl-d-aspartate receptors (NMDARs) have been associated with cortical dysfunction in a broad spectrum of neurodevelopmental and neuropsychiatric disorders including schizophrenia. However, the pathophysiological roles of synaptic vs. extrasynaptic NMDARs and their interactions with α7 nAChRs in cortical dysfunction remain largely uncharacterized. Using a combination of in vivo and in vitro models, we demonstrate that α7 nAChR gene deletion leads to specific loss of synaptic NMDARs and their coagonist, d-serine, as well as glutamatergic synaptic deficits in mouse cortex. α7 nAChR null mice had decreased cortical NMDAR expression and glutamatergic synapse formation during postnatal development. Similar reductions in NMDAR expression and glutamatergic synapse formation were revealed in cortical cultures lacking α7 nAChRs. Interestingly, synaptic, but not extrasynaptic, NMDAR currents were specifically diminished in cultured cortical pyramidal neurons as well as in acute prefrontal cortical slices of α7 nAChR null mice. Moreover, d-serine responsive synaptic NMDAR-mediated currents and levels of the d-serine synthetic enzyme serine racemase were both reduced in α7 nAChR null cortical pyramidal neurons. Our findings thus identify specific loss of synaptic NMDARs and their coagonist, d-serine, as well as glutamatergic synaptic deficits in α7 nAChR gene deletion models of cortical dysfunction, thereby implicating α7 nAChR-mediated control of synaptic NMDARs and serine racemase/d-serine pathways in cortical dysfunction underlying many neuropsychiatric and neurodevelopmental disorders, particularly those associated with deletion of human CHRNA7.
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31
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Williams CA, Battaglia A. Molecular biology of epilepsy genes. Exp Neurol 2013; 244:51-8. [DOI: 10.1016/j.expneurol.2011.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 11/28/2011] [Accepted: 12/01/2011] [Indexed: 01/05/2023]
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32
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Carvill GL, Mefford HC. Microdeletion syndromes. Curr Opin Genet Dev 2013; 23:232-9. [PMID: 23664828 DOI: 10.1016/j.gde.2013.03.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/11/2013] [Accepted: 03/25/2013] [Indexed: 01/11/2023]
Abstract
The recent explosion in the implementation of genome-wide microarray technology to discover rare, pathogenic genomic rearrangements in a variety of diseases has led to the discovery of numerous microdeletion syndromes. It is now clear that these microdeletions are associated with extensive phenotypic heterogeneity and incomplete penetrance. A subset of recurrent microdeletions underpin diverse phenotypes, including intellectual disability, autism, epilepsy and neuropsychiatric disorders. Recent studies highlight a role for additional low frequency variants, or 'second hits' to account for this variability. The implementation of massively parallel sequencing and epigenetic models may provide a powerful prospective approach to the delineation of microdeletion syndrome phenotypes.
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Affiliation(s)
- Gemma L Carvill
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
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33
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Genome-wide gene expression in a patient with 15q13.3 homozygous microdeletion syndrome. Eur J Hum Genet 2013; 21:1093-9. [PMID: 23361223 DOI: 10.1038/ejhg.2013.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/07/2012] [Accepted: 01/04/2013] [Indexed: 11/08/2022] Open
Abstract
We identified a novel homozygous 15q13.3 microdeletion in a young boy, with a complex neurodevelopmental disorder characterized by severe cerebral visual impairment with additional signs of congenital stationary night blindness, congenital hypotonia with areflexia, profound intellectual disability, and refractory epilepsy. The mechanisms by which the genes in the deleted region exert their effect are unclear. In this paper, we probed the role of downstream effects of the deletions as a contributing mechanism to the molecular basis of the observed phenotype. We analyzed gene expression of lymphoblastoid cells derived from peripheral blood of the proband and his relatives to ascertain the relative effects of the homozygous and heterozygous deletions. We identified 267 genes with apparent differential expression between the proband with the homozygous deletion and 3 age- and sex-matched typically developing controls. Several of the differentially expressed genes are known to influence neurodevelopment and muscular function, and thus may contribute to the observed cognitive impairment and hypotonia. We further investigated the role of CHRNA7 by measuring TNFα modulation (a potentially important pathway in regulating synaptic plasticity). We found that the cell line with the homozygous deletion lost the ability to inhibit the activation of tumor necrosis factor-α secretion. Our findings suggest downstream genes that may have been altered by the 15q13.3 homozygous deletion, and thus contributed to the severe developmental encephalopathy of the proband. Furthermore, we show that a potentially important pathway in learning and development is affected by the deletion of CHRNA7.
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Hoppman-Chaney N, Wain K, Seger PR, Superneau DW, Hodge JC. Identification of single gene deletions at 15q13.3: further evidence that CHRNA7 causes the 15q13.3 microdeletion syndrome phenotype. Clin Genet 2012; 83:345-51. [PMID: 22775350 DOI: 10.1111/j.1399-0004.2012.01925.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/29/2012] [Accepted: 06/29/2012] [Indexed: 11/29/2022]
Abstract
The 15q13.3 microdeletion syndrome (OMIM #612001) is characterized by a wide range of phenotypic features, including intellectual disability, seizures, autism, and psychiatric conditions. This deletion is inherited in approximately 75% of cases and has been found in mildly affected and normal parents, consistent with variable expressivity and incomplete penetrance. The common deletion is approximately 2 Mb and contains several genes; however, the gene(s) responsible for the resulting clinical features have not been clearly defined. Recently, four probands were reported with small deletions including only the CHRNA7 gene. These patients showed a wide range of phenotypic features similar to those associated with the larger 15q13.3 microdeletion. To further correlate genotype and phenotype, we queried our database of >15,000 patients tested in the Mayo Clinic Cytogenetics Laboratory from 2008 to 2011 and identified 19 individuals (10 probands and 9 family members) with isolated heterozygous CHRNA7 gene deletions. All but two infants displayed multiple features consistent with 15q13.3 microdeletion syndrome. We also identified the first de novo deletion confined to CHRNA7 as well as the second known case with homozygous deletion of CHRNA7 only. These results provide further evidence implicating CHRNA7 as the gene responsible for the clinical findings associated with 15q13.3 microdeletion.
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Affiliation(s)
- N Hoppman-Chaney
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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36
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Mefford HC, Yendle SC, Hsu C, Cook J, Geraghty E, McMahon JM, Eeg-Olofsson O, Sadleir LG, Gill D, Ben-Zeev B, Lerman-Sagie T, Mackay M, Freeman JL, Andermann E, Pelakanos JT, Andrews I, Wallace G, Eichler EE, Berkovic SF, Scheffer IE. Rare copy number variants are an important cause of epileptic encephalopathies. Ann Neurol 2011; 70:974-85. [PMID: 22190369 PMCID: PMC3245646 DOI: 10.1002/ana.22645] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Rare copy number variants (CNVs)--deletions and duplications--have recently been established as important risk factors for both generalized and focal epilepsies. A systematic assessment of the role of CNVs in epileptic encephalopathies, the most devastating and often etiologically obscure group of epilepsies, has not been performed. METHODS We evaluated 315 patients with epileptic encephalopathies characterized by epilepsy and progressive cognitive impairment for rare CNVs using a high-density, exon-focused, whole-genome oligonucleotide array. RESULTS We found that 25 of 315 (7.9%) of our patients carried rare CNVs that may contribute to their phenotype, with at least one-half being clearly or likely pathogenic. We identified 2 patients with overlapping deletions at 7q21 and 2 patients with identical duplications of 16p11.2. In our cohort, large deletions were enriched in affected individuals compared to controls, and 4 patients harbored 2 rare CNVs. We screened 2 novel candidate genes found within the rare CNVs in our cohort but found no mutations in our patients with epileptic encephalopathies. We highlight several additional novel candidate genes located in CNV regions. INTERPRETATION Our data highlight the significance of rare CNVs in the epileptic encephalopathies, and we suggest that CNV analysis should be considered in the genetic evaluation of these patients. Our findings also highlight novel candidate genes for further study.
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Affiliation(s)
- Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA.
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Abstract
With the burgeoning array of molecular tests available in the epilepsies, the clinician needs to know which tests to order for each patient. Epileptic encephalopathies are the most important clinical group for genetic testing with an increasing number of distinctive epilepsy syndromes being recognized. Identification of the causative mutation affects treatment as well as prognostic and genetic counseling.
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Pharmacotherapeutic Implications of the Association Between Genomic Instability at Chromosome 15q13.3 and Autism Spectrum Disorders. Clin Neuropharmacol 2011; 34:203-5. [DOI: 10.1097/wnf.0b013e31823a1247] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Liao J, DeWard SJ, Madan-Khetarpal S, Surti U, Hu J. A small homozygous microdeletion of 15q13.3 including the CHRNA7 gene in a girl with a spectrum of severe neurodevelopmental features. Am J Med Genet A 2011; 155A:2795-800. [PMID: 21990074 DOI: 10.1002/ajmg.a.34237] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 07/10/2011] [Indexed: 11/08/2022]
Abstract
A broad spectrum of neurodevelopmental and psychiatric disorders with variable expressivity has been reported to be associated with 15q13.3 heterozygous microdeletions. Using oligonucleotide-based array-CGH analysis, we identified a small homozygous 15q13.3 deletion in a 6-year-old girl with significant global developmental delay, severe hypotonia, cortical visual impairment, staring spell seizure, and abnormal electroencephalogram. She inherited this deletion from both parents, each of them being a heterozygous carrier. With a minimum size of 410 kb, it is the smallest 15q13.3 homozygous microdeletion reported to date and contains only the CHRNA7 gene. By comparing the phenotype of our patient with that of the other four previously reported cases with larger homozygous or compound heterozygous deletions, we conclude that patients with homozygous deletion of 15q13.3 have consistent clinical features and loss of CHRNA7 gene alone is sufficient to cause the majority of clinical features found in these patients.
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Affiliation(s)
- Jun Liao
- Pittsburgh Cytogenetics Laboratory, Center for Medical Genetics and Genomics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
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40
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Joober R. The 1000 Genomes Project: deep genomic sequencing waiting for deep psychiatric phenotyping. J Psychiatry Neurosci 2011; 36:147-9. [PMID: 21496442 PMCID: PMC3080510 DOI: 10.1503/jpn.110026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Ridha Joober
- Correspondence to: Dr. R. Joober, Douglas Hospital Research Centre, Frank B. Common Pavilion, 6875 blvd. LaSalle, Verdun QC H4H 1R3;
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41
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Spielmann M, Reichelt G, Hertzberg C, Trimborn M, Mundlos S, Horn D, Klopocki E. Homozygous deletion of chromosome 15q13.3 including CHRNA7 causes severe mental retardation, seizures, muscular hypotonia, and the loss of KLF13 and TRPM1 potentially cause macrocytosis and congenital retinal dysfunction in siblings. Eur J Med Genet 2011; 54:e441-5. [PMID: 21596161 DOI: 10.1016/j.ejmg.2011.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/12/2011] [Indexed: 10/18/2022]
Abstract
The heterozygous 15q13.3 microdeletion syndrome (MIM #612001) was first described by Sharp et al. in 2008. So far four patients with 15q13.3 homozygous or compound heterozygous microdeletions have been identified. Here we report a non-consanguineous family with two affected siblings carrying a homozygous microdeletion of ∼1.5 Mb at the 15q13.3 locus. They presented with congenital retinal dysfunction, refractory epilepsy, encephalopathy, mental retardation, repetitive hand movements, severe muscular hypotonia and macrocytosis. Dysmorphic facial features are synophrys and bilateral proptosis. The siblings carry a homozygous microdeletion at 15q13.3 of ∼1.5 Mb including the genes ARHGAP11B, MTMR15, MTMR10, TRPM1, KLF13, OTUD7A, and CHRNA7. The absence of CHRNA7 has been suggested as a cause of refractory seizures. According to knock-out experiments the deletion of KLF13 could be an explanation for macrocytosis. The homozygous loss of TRPM1 could be a possible explanation for congenital retinal dysfunction.
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Affiliation(s)
- Malte Spielmann
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany
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