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Frohlich J, Reiter LT, Saravanapandian V, DiStefano C, Huberty S, Hyde C, Chamberlain S, Bearden CE, Golshani P, Irimia A, Olsen RW, Hipp JF, Jeste SS. Mechanisms underlying the EEG biomarker in Dup15q syndrome. Mol Autism 2019; 10:29. [PMID: 31312421 PMCID: PMC6609401 DOI: 10.1186/s13229-019-0280-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/11/2019] [Indexed: 12/11/2022] Open
Abstract
Background Duplications of 15q11.2-q13.1 (Dup15q syndrome), including the paternally imprinted gene UBE3A and three nonimprinted gamma-aminobutyric acid type-A (GABAA) receptor genes, are highly penetrant for neurodevelopmental disorders such as autism spectrum disorder (ASD). To guide targeted treatments of Dup15q syndrome and other forms of ASD, biomarkers are needed that reflect molecular mechanisms of pathology. We recently described a beta EEG phenotype of Dup15q syndrome, but it remains unknown which specific genes drive this phenotype. Methods To test the hypothesis that UBE3A overexpression is not necessary for the beta EEG phenotype, we compared EEG from a reference cohort of children with Dup15q syndrome (n = 27) to (1) the pharmacological effects of the GABAA modulator midazolam (n = 12) on EEG from healthy adults, (2) EEG from typically developing (TD) children (n = 14), and (3) EEG from two children with duplications of paternal 15q (i.e., the UBE3A-silenced allele). Results Peak beta power was significantly increased in the reference cohort relative to TD controls. Midazolam administration recapitulated the beta EEG phenotype in healthy adults with a similar peak frequency in central channels (f = 23.0 Hz) as Dup15q syndrome (f = 23.1 Hz). Both paternal Dup15q syndrome cases displayed beta power comparable to the reference cohort. Conclusions Our results suggest a critical role for GABAergic transmission in the Dup15q syndrome beta EEG phenotype, which cannot be explained by UBE3A dysfunction alone. If this mechanism is confirmed, the phenotype may be used as a marker of GABAergic pathology in clinical trials for Dup15q syndrome.
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Affiliation(s)
- Joel Frohlich
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, Basel, Switzerland
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, CA 90095 USA
| | - Lawrence T. Reiter
- Departments of Neurology, Pediatrics and Anatomy & Neurobiology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link, Memphis, TN 415 USA
| | - Vidya Saravanapandian
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
| | - Charlotte DiStefano
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
| | - Scott Huberty
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
- McGill University, MUHC Research Institute, 5252, boul. de Maisonneuve Ouest, 3E.19, Montreal, QC H4A 3S5 Canada
| | - Carly Hyde
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
| | - Stormy Chamberlain
- Genetics and Genome Sciences, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6403 USA
| | - Carrie E. Bearden
- Department of Psychiatry and Biobehavioral Sciences and Department of Psychology, University of California Los Angeles, Suite A7-460, 760 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Peyman Golshani
- Department of Neurology and Psychiatry, David Geffen School of Medicine, 710 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Andrei Irimia
- Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Ave., Suite 228C, California, Los Angeles 90089 USA
| | - Richard W. Olsen
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, California, Los Angeles 90095 USA
| | - Joerg F. Hipp
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, Basel, Switzerland
| | - Shafali S. Jeste
- Center for Autism Research and Treatment, University of California Los Angeles, Semel Institute for Neuroscience, Los Angeles, CA 90024 USA
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GABA A receptor subunit gene polymorphisms predict symptom-based and developmental deficits in Chinese Han children and adolescents with autistic spectrum disorders. Sci Rep 2017; 7:3290. [PMID: 28607477 PMCID: PMC5468250 DOI: 10.1038/s41598-017-03666-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/02/2017] [Indexed: 12/29/2022] Open
Abstract
GABAA receptor subunit genes GABRB3, GABRA5, and GABRG3 located on chromosome 15q11-q13 have been implicated in the etiology of autistic spectrum disorders (ASD). This study intended to investigate the possible role of single-nucleotide polymorphisms (SNPs) present in GABRB3 (rs2081648 and rs1426217), GABRA5 (rs35586628), and GABRG3 (rs208129) genes in ASD susceptibility and symptom-based and developmental phenotypes of ASD in Chinese Han children and adolescents. 99 ASD patients and 231 age- and gender- frequency-matched typical developing (TD) controls were tested by TaqMan® genotyping assay. Symptom-based phenotypes were evaluated by Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC), and developmental phenotypes were assessed by Early Childhood Development Questionnaire (ECDQ) in ASD patients. Three haplotypes and global χ 2 test of all SNPs demonstrated significant associations between ASD and TD groups. Besides, GABRB3 rs2081648, GABRA5 rs35586628, and GABRG3 rs208129 polymorphisms were associated with symptom-based deficits in social interaction, sensorimotor and somatosensory coordination, visual response, imitation, activity level, language expression and adaptability. Developmental abnormalities in late emergences of social interaction and fine motor were detected in GABRB3 rs2081648 polymorphism. Overall results indicated that gene synergy may participate in ASD pathogenesis, and GABAA receptor gene polymorphisms can predict symptom-based and developmental deficits in ASD individuals.
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Delahanty RJ, Kang J, Brune CW, Kistner EO, Courchesne E, Cox NJ, Cook EH, Macdonald RL, Sutcliffe JS. Maternal transmission of a rare GABRB3 signal peptide variant is associated with autism. Mol Psychiatry 2011; 16:86-96. [PMID: 19935738 PMCID: PMC3428055 DOI: 10.1038/mp.2009.118] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Maternal 15q11-q13 duplication is the most common copy number variant in autism, accounting for ∼1-3% of cases. The 15q11-q13 region is subject to epigenetic regulation, and genomic copy number losses and gains cause genomic disorders in a parent-of-origin-specific manner. One 15q11-q13 locus encodes the GABA(A) receptor β3 subunit gene (GABRB3), which has been implicated by several studies in both autism and absence epilepsy, and the co-morbidity of epilepsy in autism is well established. We report that maternal transmission of a GABRB3 signal peptide variant (P11S), previously implicated in childhood absence epilepsy, is associated with autism. An analysis of wild-type and mutant β3 subunit-containing α1β3γ2 or α3β3γ2 GABA(A) receptors shows reduced whole-cell current and decreased β3 subunit protein on the cell surface due to impaired intracellular β3 subunit processing. We thus provide the first evidence of an association between a specific GABA(A) receptor defect and autism, direct evidence that this defect causes synaptic dysfunction that is autism relevant and the first maternal risk effect in the 15q11-q13 autism duplication region that is linked to a coding variant.
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Affiliation(s)
- Ryan J. Delahanty
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
| | - Jingqiong Kang
- Department of Neurology, Vanderbilt University, Nashville, TN
| | - Camille W. Brune
- Department of Psychiatry, Institute for Juvenile Research, University of Illinois at Chicago, Chicago, IL
| | - Emily O. Kistner
- Department of Health Studies, The University of Chicago, Chicago, IL
| | - Eric Courchesne
- Department of Neurosciences, University of California San Diego, La Jolla, CA
| | - Nancy J. Cox
- Department of Medicine, The University of Chicago, Chicago, IL
| | - Edwin H. Cook
- Department of Psychiatry, Institute for Juvenile Research, University of Illinois at Chicago, Chicago, IL
| | | | - James S. Sutcliffe
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN,Department of Psychiatry, Vanderbilt University, Nashville, TN
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Autism in adults. New biologicial findings and their translational implications to the cost of clinical services. Brain Res 2010; 1380:22-33. [PMID: 20969835 DOI: 10.1016/j.brainres.2010.10.042] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/22/2010] [Accepted: 10/13/2010] [Indexed: 11/21/2022]
Abstract
There is increasing evidence that children with autism spectrum disorder (ASD) have differences in brain growth trajectory. However, the neurobiological basis of ASD in adults is poorly understood. We report evidence that brain anatomy and aging in people with ASD is significantly different as compared to controls-so that in adulthood they no longer have a significantly larger overall brain volume, but they do have anatomical and functional abnormalities in frontal lobe, basal ganglia and the limbic system. Further we present preliminary evidence that females have significantly greater abnormalities in brain than males to express the same symptom severity of ASD (i.e. the female brain is "protective" against developing ASD). Also we present preliminary evidence that, in adults, clinical services for autism in the United Kingdom are experiencing very significantly increased demand; but that just over 50% of people seeking a diagnosis from one expert service do not have ASD. This consumes very significant health care resources, and so we need to identify new cost-effective methods to aid current diagnostic practice. We present initial evidence offering proof of concept that brain anatomy can be used to accurately distinguish adults with autism from healthy controls, and from some other neurodevelopmental disorders (ADHD). Hence further studies are required to determine if sMRI can become an aid to current diagnostic practice in young adults with ASD. Lastly we report evidence that differences in serotonin, glutamate and GABA may partially explain neuroanatomical and neurofunctional abnormalities in people with ASD, and that genetic influences on brain maturation vary across the lifespan (with 5-HT transporter polymorphisms having significant modulatory effects in children but not adults).
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Bremer A, Giacobini M, Nordenskjöld M, Brøndum-Nielsen K, Mansouri M, Dahl N, Anderlid B, Schoumans J. Screening for copy number alterations in loci associated with autism spectrum disorders by two-color multiplex ligation-dependent probe amplification. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:280-5. [PMID: 19319887 DOI: 10.1002/ajmg.b.30954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The autism spectrum disorder (ASD) is a heterogenous condition characterized by impaired socialization and communication in association with stereotypic behaviors. ASD is highly heritable and heterogeneous with a complex genetic etiology. Recurrent submicroscopic deletions or duplications have been identified in a subgroup of individuals with ASD using array technology. Adequate genetic testing for these genomic imbalances have not yet been widely implemented in the diagnostic setting due to lack of feasible and cost-effective methods as well as difficulties to interpret the clinical significance of these small copy number variants (CNVs). We developed a multiplex ligation-dependent probe amplification (MLPA) assay to investigate its usefulness for detection of copy number alterations (CNAs) in autistic patients. This test proved to be easy to perform, fast, cost-effective, and suitable for reliable detection of multiple loci in a single reaction. We screened 148 autistic patients for 15 different loci covering 26 genes and found a 15q11-13 interstitial duplication that had escaped detection by conventional karyotyping in 1.3% of the patients. Synthetic probe MLPA allows for a flexible analysis of a continuously increasing number of CNAs associated with autism. Our result show that MLPA assay is an easy and cost-effective method for the identification of selected CNAs in diagnostic laboratories.
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Affiliation(s)
- Anna Bremer
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
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Walker MA. Treatment of autism spectrum disorders: neurotransmitter signaling pathways involved in motivation and reward as therapeutic targets. Expert Opin Ther Targets 2008; 12:949-67. [PMID: 18620518 DOI: 10.1517/14728222.12.8.949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND There is a growing body of literature describing the etiology of autism spectrum disorders (ASD). Some of the targets suggested belong to neurochemical transmitter pathways implicated in the behavior and motivation reward pathway. OBJECTIVE To examine data linking potential targets to ASD and the feasibility of developing drugs targeting these pathways. While the inhibitors are mostly being developed for other indications, it is beneficial to examine them to determine the responsiveness of the targets to small-molecule modulation. METHODS A search in Medline and Scifinder for articles concerning relevant targets in the context of ASD and their relation to the reward signaling pathway. RESULTS There is evidence suggesting that behaviors controlled by these targets are related to behaviors exhibited by individuals with ASD. The targets appear to be involved in neurotransmitter pathways controlling motivation and reward, further implicating this system in ASD. Sufficient research has been conducted to identify lead compounds for discovering agents for treatment of ASD.
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Affiliation(s)
- Michael A Walker
- Bristol-Myers Squibb Co., Medicinal Chemistry, Research and Development, Wallingford, CT, USA.
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Windelinckx A, Vlietinck R, Aerssens J, Beunen G, Thomis MAI. Selection of genes and single nucleotide polymorphisms for fine mapping starting from a broad linkage region. Twin Res Hum Genet 2008; 10:871-85. [PMID: 18179400 DOI: 10.1375/twin.10.6.871] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Fine mapping of linkage peaks is one of the great challenges facing researchers who try to identify genes and genetic variants responsible for the variation in a certain trait or complex disease. Once the trait is linked to a certain chromosomal region, most studies use a candidate gene approach followed by a selection of polymorphisms within these genes, either based on their possibility to be functional, or based on the linkage disequilibrium between adjacent markers. For both candidate gene selection and SNP selection, several approaches have been described, and different software tools are available. However, mastering all these information sources and choosing between the different approaches can be difficult and time-consuming. Therefore, this article lists several of these in silico procedures, and the authors describe an empirical two-step fine mapping approach, in which candidate genes are prioritized using a bioinformatics approach (ENDEAVOUR), and the top genes are chosen for further SNP selection with a linkage disequilibrium based method (Tagger). The authors present the different actions that were applied within this approach on two previously identified linkage regions for muscle strength. This resulted in the selection of 331 polymorphisms located in 112 different candidate genes out of an initial set of 23,300 SNPs.
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Affiliation(s)
- An Windelinckx
- Research Center for Exercise and Health, Department of Biomedical Kinesiology, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium
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Bonati MT, Russo S, Finelli P, Valsecchi MR, Cogliati F, Cavalleri F, Roberts W, Elia M, Larizza L. Evaluation of autism traits in Angelman syndrome: a resource to unfold autism genes. Neurogenetics 2007; 8:169-78. [PMID: 17415598 DOI: 10.1007/s10048-007-0086-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2006] [Accepted: 03/07/2007] [Indexed: 12/11/2022]
Abstract
Linkage and cytogenetics studies have found the Angelman syndrome (AS) chromosomal region to be of relevance to autism disorder (AD) or autism spectrum disorder (ASD). Autism is considered part of the behavioural phenotype in AS based on formal autism assessments (autism diagnostic interview-revised [ADI-R] and autism diagnostic observation schedule [ADOS]), which have mainly addressed the deleted AS group. We explored 23 AS patients including all genetic subtypes and made a co-morbid diagnosis of AD/ASD in 14/23 (61%), which does not include 4 cases classified within the broader autism spectrum disorder (bASD). Deletions accounted for the main fraction (35%), ubiquitin-protein ligase E3A (UBE3A) mutation represented 13%, imprinting defects and uniparental disomy 9 and 4%, respectively. UBE3A mutations due to lack of the homologous to the E6-associated protein carboxyl terminus domain (n = 3) were associated with the ASD, while more distal mutations (n = 3) seem to escape from a co-morbid diagnosis of autism/autism spectrum. Differences in severity of autistic features were seen across subtypes of AS, with some behavioural features being unique to AS and some representing all forms of developmental disability. Autism signs (poor/lack of eye contact, showing, spontaneous initiation of joint attention, social quality of overtures [ADOS algorithm items for Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV)/International Statistical Classification of Diseases and Related Health Problems-10 (ICD-10) autism diagnosis belonging to the reciprocal social interaction domain]) discriminating all the co-morbid AS categories from non-autistic AS belonged to the social interaction domain. Impairments in the communication domain (gestures, pointing, use of another's body, frequency of vocalisation towards others [ADOS algorithm items for DSM-IV/ICD-10 autism diagnosis belonging to the communication domain]) justified classification of co-morbid AD/ASD vs the classification of less affected bASD. Evaluation of the behaviour domain suggested that repetitive sensory and motor behaviours correlate with a low developmental profile rather than being specific to autism.
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Affiliation(s)
- Maria Teresa Bonati
- Clinic of Medical Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy.
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