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Qin D, Wu S, Chen Y, Hu X. Behavioral screening tools for identifying autism in macaques: existing and promising tests. Brain Res Bull 2019; 146:87-93. [PMID: 30605712 DOI: 10.1016/j.brainresbull.2018.12.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/11/2018] [Accepted: 12/28/2018] [Indexed: 02/05/2023]
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2
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Forsberg SL, Ilieva M, Maria Michel T. Epigenetics and cerebral organoids: promising directions in autism spectrum disorders. Transl Psychiatry 2018; 8:14. [PMID: 29317608 PMCID: PMC5802583 DOI: 10.1038/s41398-017-0062-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/26/2017] [Indexed: 01/04/2023] Open
Abstract
Autism spectrum disorders (ASD) affect 1 in 68 children in the US according to the Centers for Disease Control and Prevention (CDC). It is characterized by impairments in social interactions and communication, restrictive and repetitive patterns of behaviors, and interests. Owing to disease complexity, only a limited number of treatment options are available mainly for children that alleviate but do not cure the debilitating symptoms. Studies confirm a genetic link, but environmental factors, such as medications, toxins, and maternal infection during pregnancy, as well as birth complications also play a role. Some studies indicate a set of candidate genes with different DNA methylation profiles in ASD compared to healthy individuals. Thus epigenetic alterations could help bridging the gene-environment gap in deciphering the underlying neurobiology of autism. However, epigenome-wide association studies (EWAS) have mainly included a very limited number of postmortem brain samples. Hence, cellular models mimicking brain development in vitro will be of great importance to study the critical epigenetic alterations and when they might happen. This review will give an overview of the state of the art concerning knowledge on epigenetic changes in autism and how new, cutting edge expertise based on three-dimensional (3D) stem cell technology models (brain organoids) can contribute in elucidating the multiple aspects of disease mechanisms.
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Affiliation(s)
- Sheena Louise Forsberg
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mirolyuba Ilieva
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark.
| | - Tanja Maria Michel
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Psychiatry, Psychiatry in the region of Southern Denmark, Odense, Denmark
- Odense Center for Applied Neuroscience BRIDGE, University of Southern Denmark, Psychiatry in the Region of Southern Denmark, Odense University Hospital, Odense, Denmark
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Varghese M, Keshav N, Jacot-Descombes S, Warda T, Wicinski B, Dickstein DL, Harony-Nicolas H, De Rubeis S, Drapeau E, Buxbaum JD, Hof PR. Autism spectrum disorder: neuropathology and animal models. Acta Neuropathol 2017; 134:537-566. [PMID: 28584888 PMCID: PMC5693718 DOI: 10.1007/s00401-017-1736-4] [Citation(s) in RCA: 276] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorder (ASD) has a major impact on the development and social integration of affected individuals and is the most heritable of psychiatric disorders. An increase in the incidence of ASD cases has prompted a surge in research efforts on the underlying neuropathologic processes. We present an overview of current findings in neuropathology studies of ASD using two investigational approaches, postmortem human brains and ASD animal models, and discuss the overlap, limitations, and significance of each. Postmortem examination of ASD brains has revealed global changes including disorganized gray and white matter, increased number of neurons, decreased volume of neuronal soma, and increased neuropil, the last reflecting changes in densities of dendritic spines, cerebral vasculature and glia. Both cortical and non-cortical areas show region-specific abnormalities in neuronal morphology and cytoarchitectural organization, with consistent findings reported from the prefrontal cortex, fusiform gyrus, frontoinsular cortex, cingulate cortex, hippocampus, amygdala, cerebellum and brainstem. The paucity of postmortem human studies linking neuropathology to the underlying etiology has been partly addressed using animal models to explore the impact of genetic and non-genetic factors clinically relevant for the ASD phenotype. Genetically modified models include those based on well-studied monogenic ASD genes (NLGN3, NLGN4, NRXN1, CNTNAP2, SHANK3, MECP2, FMR1, TSC1/2), emerging risk genes (CHD8, SCN2A, SYNGAP1, ARID1B, GRIN2B, DSCAM, TBR1), and copy number variants (15q11-q13 deletion, 15q13.3 microdeletion, 15q11-13 duplication, 16p11.2 deletion and duplication, 22q11.2 deletion). Models of idiopathic ASD include inbred rodent strains that mimic ASD behaviors as well as models developed by environmental interventions such as prenatal exposure to sodium valproate, maternal autoantibodies, and maternal immune activation. In addition to replicating some of the neuropathologic features seen in postmortem studies, a common finding in several animal models of ASD is altered density of dendritic spines, with the direction of the change depending on the specific genetic modification, age and brain region. Overall, postmortem neuropathologic studies with larger sample sizes representative of the various ASD risk genes and diverse clinical phenotypes are warranted to clarify putative etiopathogenic pathways further and to promote the emergence of clinically relevant diagnostic and therapeutic tools. In addition, as genetic alterations may render certain individuals more vulnerable to developing the pathological changes at the synapse underlying the behavioral manifestations of ASD, neuropathologic investigation using genetically modified animal models will help to improve our understanding of the disease mechanisms and enhance the development of targeted treatments.
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Affiliation(s)
- Merina Varghese
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Neha Keshav
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sarah Jacot-Descombes
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Unit of Psychiatry, Department of Children and Teenagers, University Hospitals and School of Medicine, Geneva, CH-1205, Switzerland
| | - Tahia Warda
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Bridget Wicinski
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Dara L Dickstein
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Hala Harony-Nicolas
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Elodie Drapeau
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Joseph D Buxbaum
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Patrick R Hof
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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4
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Sjaarda CP, Hecht P, McNaughton AJM, Zhou A, Hudson ML, Will MJ, Smith G, Ayub M, Liang P, Chen N, Beversdorf D, Liu X. Interplay between maternal Slc6a4 mutation and prenatal stress: a possible mechanism for autistic behavior development. Sci Rep 2017; 7:8735. [PMID: 28821725 PMCID: PMC5562880 DOI: 10.1038/s41598-017-07405-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/23/2017] [Indexed: 02/05/2023] Open
Abstract
The low activity allele of the maternal polymorphism, 5HTTLPR, in the serotonin transporter, SLC6A4, coupled with prenatal stress is reported to increase the risk for children to develop autism spectrum disorder (ASD). Similarly, maternal Slc6a4 knock-out and prenatal stress in rodents results in offspring demonstrating ASD-like characteristics. The present study uses an integrative genomics approach to explore mechanistic changes in early brain development in mouse embryos exposed to this maternal gene-environment phenomenon. Restraint stress was applied to pregnant Slc6a4 +/+ and Slc6a4 +/- mice and post-stress embryonic brains were assessed for whole genome level profiling of methylome, transcriptome and miRNA using Next Generation Sequencing. Embryos of stressed Slc6a4 +/+ dams exhibited significantly altered methylation profiles and differential expression of 157 miRNAs and 1009 genes affecting neuron development and cellular adhesion pathways, which may function as a coping mechanism to prenatal stress. In striking contrast, the response of embryos of stressed Slc6a4 +/- dams was found to be attenuated, shown by significantly reduced numbers of differentially expressed genes (458) and miRNA (0) and genome hypermethylation. This attenuated response may pose increased risks on typical brain development resulting in development of ASD-like characteristics in offspring of mothers with deficits in serotonin related pathways during stressful pregnancies.
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Affiliation(s)
- Calvin P Sjaarda
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada.,Queen's Genomics Lab at Ongwanada (QGLO), Ongwanada Resource Center, Kingston, Ontario, Canada
| | - Patrick Hecht
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, Missouri, USA
| | - Amy J M McNaughton
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada.,Queen's Genomics Lab at Ongwanada (QGLO), Ongwanada Resource Center, Kingston, Ontario, Canada
| | - Audrina Zhou
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada.,Queen's Genomics Lab at Ongwanada (QGLO), Ongwanada Resource Center, Kingston, Ontario, Canada
| | - Melissa L Hudson
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada.,Queen's Genomics Lab at Ongwanada (QGLO), Ongwanada Resource Center, Kingston, Ontario, Canada
| | - Matt J Will
- Psychological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Garth Smith
- Department of Pediatrics, Queen's University, Kingston, Ontario, Canada.,Child Development Centre, Hotel Dieu Hospital, Kingston, Ontario, Canada
| | - Muhammad Ayub
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Nansheng Chen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - David Beversdorf
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, Missouri, USA.,Departments of Radiology, Neurology, and Psychological Sciences, and the Thompson Center for Autism and Neurodevelopmental Disorders, and William and Nancy Thompson Endowed Chair in Radiology, University of Missouri, Columbia, Missouri, USA
| | - Xudong Liu
- Department of Psychiatry, Queen's University, Kingston, Ontario, Canada. .,Queen's Genomics Lab at Ongwanada (QGLO), Ongwanada Resource Center, Kingston, Ontario, Canada.
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5
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Wei H, Liang F, Meng G, Nie Z, Zhou R, Cheng W, Wu X, Feng Y, Wang Y. Redox/methylation mediated abnormal DNA methylation as regulators of ambient fine particulate matter-induced neurodevelopment related impairment in human neuronal cells. Sci Rep 2016; 6:33402. [PMID: 27624276 PMCID: PMC5022064 DOI: 10.1038/srep33402] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/24/2016] [Indexed: 12/22/2022] Open
Abstract
Fine particulate matter (PM2.5) has been implicated as a risk factor for neurodevelopmental disorders including autism in children. However, the underlying biological mechanism remains unclear. DNA methylation is suggested to be a fundamental mechanism for the neuronal responses to environmental cues. We prepared whole particle of PM2.5 (PM2.5), water-soluble extracts (Pw), organic extracts (Po) and carbon core component (Pc) and characterized their chemical constitutes. We found that PM2.5 induced significant redox imbalance, decreased the levels of intercellular methyl donor S-adenosylmethionine and caused global DNA hypomethylation. Furthermore, PM2.5 exposure triggered gene-specific promoter DNA hypo- or hypermethylation and abnormal mRNA expression of autism candidate genes. PM2.5-induced DNA hypermethylation in promoter regions of synapse related genes were associated with the decreases in their mRNA and protein expression. The inhibiting effects of antioxidative reagents, a methylation-supporting agent and a DNA methyltransferase inhibitor demonstrated the involvement of redox/methylation mechanism in PM2.5-induced abnormal DNA methylation patterns and synaptic protein expression. The biological effects above generally followed a sequence of PM2.5 ≥ Pwo > Po > Pw > Pc. Our results implicated a novel epigenetic mechanism for the neurodevelopmental toxicity of particulate air pollution, and that eliminating the chemical components could mitigate the neurotoxicity of PM2.5.
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Affiliation(s)
- Hongying Wei
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Fan Liang
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Ge Meng
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Zhiqing Nie
- Shanghai Jiao Tong University School of Environmental Science and Engineering, Shanghai, 200240, China
| | - Ren Zhou
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Wei Cheng
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Xiaomeng Wu
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Yan Feng
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China
| | - Yan Wang
- Shanghai Jiao Tong University School of Public Health; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital, Shanghai 200025, China.,Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
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6
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Pawlowski JW, Kellicker N, Bobst CE, Kaltashov IA. Assessing the iron delivery efficacy of transferrin in clinical samples by native electrospray ionization mass spectrometry. Analyst 2016; 141:853-61. [PMID: 26646585 PMCID: PMC4727994 DOI: 10.1039/c5an02159f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Serum transferrin is a key player in iron homeostasis, and its ability to deliver iron to cells via the endosomal pathway critically depends on the presence of carbonate that binds this protein synergistically with ferric ion. Oxalate is another ubiquitous anionic species that can act as a synergistic anion, and in fact its interaction with transferrin is notably stronger compared to carbonate, preventing the protein from releasing the metal in the endosomal environment. While this raises concerns that high oxalate levels in plasma may interfere with iron delivery to tissues, concentration of free oxalate in blood appears to be a poor predictor of impeded availability of iron, as previous studies showed that it cannot displace carbonate from ferro-transferrin on a physiologically relevant time scale under the conditions mimicing plasma. In this work we present a new method that allows different forms of ferro-transferrin (carbonate- vs. oxalate-bound) to be distinguished from each other by removing this protein from plasma without altering the composition of the protein/metal/synergistic anion complexes, and determining their accurate masses using native electrospray ionization mass spectrometry (ESI MS). The new method has been validated using a mixture of recombinant proteins, followed by its application to the analysis of clinical samples of human plasma, demonstrating that native ESI MS can be used in clinical analysis.
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Affiliation(s)
- Jake W Pawlowski
- University of Massachusetts-Amherst, Department of Chemistry, 240 Thatcher Drive, Life Sciences Laboratories N369, Amherst, MA 01003, USA.
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7
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Quantifying narrative ability in autism spectrum disorder: a computational linguistic analysis of narrative coherence. J Autism Dev Disord 2015; 44:3016-25. [PMID: 24915929 DOI: 10.1007/s10803-014-2158-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Autism is a neurodevelopmental disorder characterized by serious difficulties with the social use of language, along with impaired social functioning and ritualistic/repetitive behaviors (American Psychiatric Association in Diagnostic and statistical manual of mental disorders: DSM-5, 5th edn. American Psychiatric Association, Arlington, 2013). While substantial heterogeneity exists in symptom expression, impairments in language discourse skills, including narrative (or storytelling), are universally observed in autism (Tager-Flusberg et al. in Handbook on autism and pervasive developmental disorders, 3rd edn. Wiley, New York, pp 335-364, 2005). This study applied a computational linguistic tool, Latent Semantic Analysis (LSA), to objectively characterize narrative performance in high-functioning individuals with autism and typically-developing controls, across two different narrative contexts that differ in the interpersonal and cognitive demands placed on the narrator. Results indicated that high-functioning individuals with autism produced narratives comparable in semantic content to those produced by controls when narrating from a picture book, but produced narratives diminished in semantic quality in a more demanding narrative recall task. This pattern is similar to that detected from analyses of hand-coded picture book narratives in prior research, and extends findings to an additional narrative context that proves particularly challenging for individuals with autism. Results are discussed in terms of the utility of LSA as a quantitative, objective, and efficient measure of narrative ability.
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8
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Association of Copy Number Variations in Autism Spectrum Disorders: A Systematic Review. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/713109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Autism spectrum disorders (ASDs) are characterized by language impairments, social deficits, and repetitive behaviors. The onset of symptoms occurs by the age of 3 and shows a lifelong persistence. Genetics plays a major role in the etiology of ASD. Except genetics, several potential risk factors (environmental factors and epigenetics) may contribute to ASD. Copy number variations (CNVs) are the most widespread structural variations in the human genome. These variations can alter the genome structure either by deletion or by duplication. CNVs can be de novo or inherited. Chromosomal rearrangements have been detected in 5–10% of the patients with ASD and recently copy number changes ranging from a few kilobases (kb) to several megabases (Mb) in size have been reported. Recent data have also revealed that submicroscopic CNVs can have a role in ASD, and de novo CNVs seem to be a more common risk factor in sporadic compared with inherited forms of ASD. CNVs are being implicated as a contributor to the pathophysiology of complex neurodevelopmental disorders and they can affect a wide range of human phenotypes including mental retardation (MR), autism, neuropsychiatric disorders, and susceptibility to other complex traits such as HIV, Crohn’s disease, and psoriasis. This review emphasizes the major CNVs reported to date in ASD.
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Popov NT, Madjirova NP, Minkov IN, Vachev TI. Micro RNA HSA-486-3P Gene Expression Profiling in the Whole Blood of Patients with Autism. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2012.0093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Hall L, Kelley E. The contribution of epigenetics to understanding genetic factors in autism. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2013; 18:872-81. [PMID: 24126868 DOI: 10.1177/1362361313503501] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Autism spectrum disorder is a grouping of neurodevelopmental disorders characterized by deficits in social communication and language, as well as by repetitive and stereotyped behaviors. While the environment is believed to play a role in the development of autism spectrum disorder, there is now strong evidence for a genetic link to autism. Despite such evidence, studies investigating a potential single-gene cause for autism, although insightful, have been highly inconclusive. A consideration of an epigenetic approach proves to be very promising in clarifying genetic factors involved in autism. The present article is intended to provide a review of key findings pertaining to epigenetics in autism in such a way that a broader audience of individuals who do not have a strong background in genetics may better understand this highly specific and scientific content. Epigenetics refers to non-permanent heritable changes that alter expression of genes without altering the DNA sequence itself and considers the role of environment in this modulation of gene expression. This review provides a brief description of epigenetic processes, highlights evidence in the literature of epigenetic dysregulation in autism, and makes use of noteworthy findings to illustrate how a consideration of epigenetic factors can deepen our understanding of the development of autism. Furthermore, this discussion will present a promising new way for moving forward in the investigation of genetic factors within autism.
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11
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Rose'meyer R. A review of the serotonin transporter and prenatal cortisol in the development of autism spectrum disorders. Mol Autism 2013; 4:37. [PMID: 24103554 PMCID: PMC3852299 DOI: 10.1186/2040-2392-4-37] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 09/13/2013] [Indexed: 01/28/2023] Open
Abstract
The diagnosis of autism spectrum disorder (ASD) during early childhood has a profound effect not only on young children but on their families. Aside from the physical and behavioural issues that need to be dealt with, there are significant emotional and financial costs associated with living with someone diagnosed with ASD. Understanding how autism occurs will assist in preparing families to deal with ASD, if not preventing or lessening its occurrence. Serotonin plays a vital role in the development of the brain during the prenatal and postnatal periods, yet very little is known about the serotonergic systems that affect children with ASD. This review seeks to provide an understanding of the biochemistry and physiological actions of serotonin and its termination of action through the serotonin reuptake transporter (SERT). Epidemiological studies investigating prenatal conditions that can increase the risk of ASD describe a number of factors which elevate plasma cortisol levels causing such symptoms during pregnancy such as hypertension, gestational diabetes and depression. Because cortisol plays an important role in driving dysregulation of serotonergic signalling through elevating SERT production in the developing brain, it is also necessary to investigate the physiological functions of cortisol, its action during gestation and metabolic syndromes.
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Affiliation(s)
- Roselyn Rose'meyer
- School of Medical Sciences, Griffith University, Gold Coast Campus, Parklands Drive, Southport, Queensland 4222, Australia.
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12
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Siniscalco D, Cirillo A, Bradstreet JJ, Antonucci N. Epigenetic findings in autism: new perspectives for therapy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4261-73. [PMID: 24030655 PMCID: PMC3799534 DOI: 10.3390/ijerph10094261] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/14/2013] [Accepted: 09/06/2013] [Indexed: 12/22/2022]
Abstract
Autism and autism spectrum disorders (ASDs) are complex neurodevelopmental disorders characterized by dysfunctions in social interactions, communications, restricted interests, and repetitive stereotypic behaviors. Despite extensive genetic and biological research, significant controversy surrounds our understanding of the specific mechanisms of their pathogenesis. However, accumulating evidence points to the involvement of epigenetic modifications as foundational in creating ASD pathophysiology. Epigenetic modifications or the alteration of DNA transcription via variations in DNA methylation and histone modifications but without alterations in the DNA sequence, affect gene regulation. These alterations in gene expression, obtained through DNA methylation and/or histone modifications, result from transcriptional regulatory influences of environmental factors, such as nutritional deficiencies, various toxicants, immunological effects, and pharmaceuticals. As such these effects are epigenetic regulators which determine the final biochemistry and physiology of the individual. In contrast to psychopharmacological interventions, bettering our understanding of how these gene-environmental interactions create autistic symptoms should facilitate the development of therapeutic targeting of gene expression for ASD biomedical care.
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Affiliation(s)
- Dario Siniscalco
- Department of Experimental Medicine, Second University of Naples; via S. Maria di Costantinopoli, Napoli 16-80138, Italy
- Centre for Autism—La Forza del Silenzio, Caserta 81036, Italy
- Cancellautismo—Non-Profit Association for Autism Care, Florence 50132, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-0-81-566-5880; Fax: +39-0-81-566-7503
| | - Alessandra Cirillo
- Institute of Protein Biochemistry, National Research Council of Italy; Naples 80128, Italy; E-Mail:
| | | | - Nicola Antonucci
- Biomedical Centre for Autism Research and Treatment, Bari 70126, Italy; E-Mail:
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Alter MD, Kharkar R, Ramsey KE, Craig DW, Melmed RD, Grebe TA, Bay RC, Ober-Reynolds S, Kirwan J, Jones JJ, Turner JB, Hen R, Stephan DA. Autism and increased paternal age related changes in global levels of gene expression regulation. PLoS One 2011; 6:e16715. [PMID: 21379579 PMCID: PMC3040743 DOI: 10.1371/journal.pone.0016715] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 12/20/2010] [Indexed: 12/19/2022] Open
Abstract
A causal role of mutations in multiple general transcription factors in neurodevelopmental disorders including autism suggested that alterations in global levels of gene expression regulation might also relate to disease risk in sporadic cases of autism. This premise can be tested by evaluating for changes in the overall distribution of gene expression levels. For instance, in mice, variability in hippocampal-dependent behaviors was associated with variability in the pattern of the overall distribution of gene expression levels, as assessed by variance in the distribution of gene expression levels in the hippocampus. We hypothesized that a similar change in variance might be found in children with autism. Gene expression microarrays covering greater than 47,000 unique RNA transcripts were done on RNA from peripheral blood lymphocytes (PBL) of children with autism (n = 82) and controls (n = 64). Variance in the distribution of gene expression levels from each microarray was compared between groups of children. Also tested was whether a risk factor for autism, increased paternal age, was associated with variance. A decrease in the variance in the distribution of gene expression levels in PBL was associated with the diagnosis of autism and a risk factor for autism, increased paternal age. Traditional approaches to microarray analysis of gene expression suggested a possible mechanism for decreased variance in gene expression. Gene expression pathways involved in transcriptional regulation were down-regulated in the blood of children with autism and children of older fathers. Thus, results from global and gene specific approaches to studying microarray data were complimentary and supported the hypothesis that alterations at the global level of gene expression regulation are related to autism and increased paternal age. Global regulation of transcription, thus, represents a possible point of convergence for multiple etiologies of autism and other neurodevelopmental disorders.
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Affiliation(s)
- Mark D Alter
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
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Copy number variation in the dosage-sensitive 16p11.2 interval accounts for only a small proportion of autism incidence: A systematic review and meta-analysis. Genet Med 2011; 13:377-84. [DOI: 10.1097/gim.0b013e3182076c0c] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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15
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Matson JL, Sturmey P. The Genetics of Autism. INTERNATIONAL HANDBOOK OF AUTISM AND PERVASIVE DEVELOPMENTAL DISORDERS 2011. [PMCID: PMC7120060 DOI: 10.1007/978-1-4419-8065-6_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This chapter is written to make the fast-paced, expanding field of the genetics of autism accessible to those practitioners who help children with autism. New genetic knowledge and technology have quickly developed over the past 30 years, particularly within the past decade, and have made many optimistic about our ability to explain autism. Among these advances include the sequencing of the human genome (Lander et al., 2001) and the identification of common genetic variants via the HapMap project (International HapMap Consortium, 2005), and the development of cost-efficient genotyping and analysis technologies (Losh, Sullivan, Trembath, & Piven, 2008). Improvement in technology has led to improved visualization of chromosomal abnormality down to the molecular level. The four most common syndromes associated with autism include fragile X syndrome, tuberous sclerosis, 15q duplications, and untreated phenylketonuria (PKU; Costa e Silva, 2008). FXS and 15q duplications are discussed within the context of cytogenetics. TSC is illustrated within the description of linkage analysis.
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Affiliation(s)
- Johnny L. Matson
- Department of Psychology, Louisiana State University, Baton Rouge, 70803 Louisiana USA
| | - Peter Sturmey
- City University of New York, Department of Psychology, Queens College, Flushing, 11367 New York USA
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16
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Griffith GM, Hastings RP, Nash S, Hill C. Using matched groups to explore child behavior problems and maternal well-being in children with Down syndrome and autism. J Autism Dev Disord 2010; 40:610-9. [PMID: 19936904 DOI: 10.1007/s10803-009-0906-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mothers of children with Down syndrome, autism, and mixed etiology intellectual disabilities, matched on child age, gender, and communication skills (n = 19 in each group) completed measures of their child's adaptive and problem behaviors, their own parenting stress, and positive perceptions of their child. Children with autism were rated as having more problem behaviors and lower levels of social competence than children with Down syndrome and mixed etiology intellectual disabilities. Mothers of children with autism scored lower on positive perceptions of their child, and higher on stress than the other two groups. After selecting closely matched groups, we found several group differences in child behavior but little evidence of group differences in maternal outcomes.
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17
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Ronald A, Butcher LM, Docherty S, Davis OSP, Schalkwyk LC, Craig IW, Plomin R. A genome-wide association study of social and non-social autistic-like traits in the general population using pooled DNA, 500 K SNP microarrays and both community and diagnosed autism replication samples. Behav Genet 2009; 40:31-45. [PMID: 20012890 PMCID: PMC2797846 DOI: 10.1007/s10519-009-9308-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 10/14/2009] [Indexed: 10/28/2022]
Abstract
Two separate genome-wide association studies were conducted to identify single nucleotide polymorphisms (SNPs) associated with social and nonsocial autistic-like traits. We predicted that we would find SNPs associated with social and non-social autistic-like traits and that different SNPs would be associated with social and nonsocial. In Stage 1, each study screened for allele frequency differences in approximately 430,000 autosomal SNPs using pooled DNA on microarrays in high-scoring versus low-scoring boys from a general population sample (N = approximately 400/group). In Stage 2, 22 and 20 SNPs in the social and non-social studies, respectively, were tested for QTL association by individually genotyping an independent community sample of 1,400 boys. One SNP (rs11894053) was nominally associated (P < .05, uncorrected for multiple testing) with social autistic-like traits. When the sample was increased by adding females, 2 additional SNPs were nominally significant (P < .05). These 3 SNPs, however, showed no significant association in transmission disequilibrium analyses of diagnosed ASD families.
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Affiliation(s)
- Angelica Ronald
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
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18
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Kumbier E, Domes G, Herpertz-Dahlmann B, Herpertz SC. [Autism and autistic disorders. Historical and current aspects]. DER NERVENARZT 2009; 81:55-65. [PMID: 19597797 DOI: 10.1007/s00115-009-2820-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Since its first use in medical literature the meaning of the term autism has constantly changed. An historical overview indicates that in both adult and child psychiatry autism was first used to refer to a symptom of schizophrenia. Later on the use of the term in child psychiatry took a different independent course, which led to present-day conceptualization of autism, mainly due to the work of Leo Kanner and Hans Asperger. Currently autism and autistic disorders are regarded as severe developmental disorders and, due to their stable nature, have gained considerable attention in adult psychiatry. In order to better understand this development, the path from onset to reception is traced via Kanner and Asperger. In the search for central characteristics of autism, one finds restrictions in social communication and interaction, which can be explained by fundamental deficits in social cognition. These restrictions in social cognition can be considered the central characteristic of autism - one which has been a constant since the phenomenon was first described. Our historical review considers to what extent experimental psychopathological research can deepen our understanding of the disorder.
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Affiliation(s)
- E Kumbier
- Klinik und Poliklinik für Psychiatrie und Psychotherapie, Zentrum für Nervenheilkunde der Universität Rostock, Gehlsheimer Str. 20, 18147 Rostock.
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19
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Newbury DF, Warburton PC, Wilson N, Bacchelli E, Carone S, Lamb JA, Maestrini E, Volpi EV, Mohammed S, Baird G, Monaco AP. Mapping of partially overlapping de novo deletions across an autism susceptibility region (AUTS5) in two unrelated individuals affected by developmental delays with communication impairment. Am J Med Genet A 2009; 149A:588-97. [PMID: 19267418 PMCID: PMC2680219 DOI: 10.1002/ajmg.a.32704] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autism is a neurodevelopmental disorder characterized by deficits in reciprocal social interaction and communication, and repetitive and stereotyped behaviors and interests. Previous genetic studies of autism have shown evidence of linkage to chromosomes 2q, 3q, 7q, 11p, 16p, and 17q. However, the complexity and heterogeneity of the disorder have limited the success of candidate gene studies. It is estimated that 5% of the autistic population carry structural chromosome abnormalities. This article describes the molecular cytogenetic characterization of two chromosome 2q deletions in unrelated individuals, one of whom lies in the autistic spectrum. Both patients are affected by developmental disorders with language delay and communication difficulties. Previous karyotype analyses described the deletions as [46,XX,del(2)(q24.1q24.2)dn]. Breakpoint refinement by FISH mapping revealed the two deletions to overlap by approximately 1.1Mb of chromosome 2q24.1, a region which contains just one gene—potassium inwardly rectifying channel, subfamily J, member 3 (KCNJ3). However, a mutation screen of this gene in 47 autistic probands indicated that coding variants in this gene are unlikely to underlie the linkage between autism and chromosome 2q. Nevertheless, it remains possible that variants in the flanking genes may underlie evidence of linkage at this locus.
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Affiliation(s)
- Dianne F Newbury
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Headington, Oxford, UK.
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20
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Wang K, Zhang H, Ma D, Bucan M, Glessner JT, Abrahams BS, Salyakina D, Imielinski M, Bradfield JP, Sleiman PMA, Kim CE, Hou C, Frackelton E, Chiavacci R, Takahashi N, Sakurai T, Rappaport E, Lajonchere CM, Munson J, Estes A, Korvatska O, Piven J, Sonnenblick LI, Alvarez Retuerto AI, Herman EI, Dong H, Hutman T, Sigman M, Ozonoff S, Klin A, Owley T, Sweeney JA, Brune CW, Cantor RM, Bernier R, Gilbert JR, Cuccaro ML, McMahon WM, Miller J, State MW, Wassink TH, Coon H, Levy SE, Schultz RT, Nurnberger JI, Haines JL, Sutcliffe JS, Cook EH, Minshew NJ, Buxbaum JD, Dawson G, Grant SFA, Geschwind DH, Pericak-Vance MA, Schellenberg GD, Hakonarson H. Common genetic variants on 5p14.1 associate with autism spectrum disorders. Nature 2009; 459:528-33. [PMID: 19404256 DOI: 10.1038/nature07999] [Citation(s) in RCA: 699] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 03/18/2009] [Indexed: 01/03/2023]
Abstract
Autism spectrum disorders (ASDs) represent a group of childhood neurodevelopmental and neuropsychiatric disorders characterized by deficits in verbal communication, impairment of social interaction, and restricted and repetitive patterns of interests and behaviour. To identify common genetic risk factors underlying ASDs, here we present the results of genome-wide association studies on a cohort of 780 families (3,101 subjects) with affected children, and a second cohort of 1,204 affected subjects and 6,491 control subjects, all of whom were of European ancestry. Six single nucleotide polymorphisms between cadherin 10 (CDH10) and cadherin 9 (CDH9)-two genes encoding neuronal cell-adhesion molecules-revealed strong association signals, with the most significant SNP being rs4307059 (P = 3.4 x 10(-8), odds ratio = 1.19). These signals were replicated in two independent cohorts, with combined P values ranging from 7.4 x 10(-8) to 2.1 x 10(-10). Our results implicate neuronal cell-adhesion molecules in the pathogenesis of ASDs, and represent, to our knowledge, the first demonstration of genome-wide significant association of common variants with susceptibility to ASDs.
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Affiliation(s)
- Kai Wang
- Center for Applied Genomics, Children's Hospital of Philadelphia, Pennsylvania 19104, USA
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21
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Pagnamenta AT, Wing K, Sadighi Akha E, Knight SJL, Bölte S, Schmötzer G, Duketis E, Poustka F, Klauck SM, Poustka A, Ragoussis J, Bailey AJ, Monaco AP. A 15q13.3 microdeletion segregating with autism. Eur J Hum Genet 2008; 17:687-92. [PMID: 19050728 DOI: 10.1038/ejhg.2008.228] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Autism and mental retardation (MR) show high rates of comorbidity and potentially share genetic risk factors. In this study, a rare approximately 2 Mb microdeletion involving chromosome band 15q13.3 was detected in a multiplex autism family. This genomic loss lies between distal break points of the Prader-Willi/Angelman syndrome locus and was first described in association with MR and epilepsy. Together with recent studies that have also implicated this genomic imbalance in schizophrenia, our data indicate that this CNV shows considerable phenotypic variability. Further studies should aim to characterise the precise phenotypic range of this CNV and may lead to the discovery of genetic or environmental modifiers.
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22
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The 'fractionable autism triad': a review of evidence from behavioural, genetic, cognitive and neural research. Neuropsychol Rev 2008; 18:287-304. [PMID: 18956240 DOI: 10.1007/s11065-008-9076-8] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 09/13/2008] [Indexed: 10/21/2022]
Abstract
Autism is diagnosed on the basis of a triad of impairments in social interaction, communication, and flexible imaginative functions (with restricted and repetitive behaviors and interests; RRBIs). There has been a strong presumption that these different features of the syndrome are strongly intertwined and proceed from a common cause at the genetic, cognitive and neural levels. In this review we examine evidence for an alternative approach, considering the triad as largely 'fractionable'. We present evidence from our own twin studies, and review relevant literature on autism and autistic-like traits in other groups. We suggest that largely independent genes may operate on social skills/impairments, communication abilities, and RRBIs, requiring a change in molecular-genetic research approaches. At the cognitive level, we suggest that satisfactory accounts exist for each of the triad domains, but no single unitary account can explain both social and nonsocial features of autism. We discuss the implications of the fractionable-triad approach for both diagnosis and future research directions.
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Abstract
Autism is a severe neurodevelopmental disorder that is typically diagnosed by 3 years of age. Core symptoms of autism include profound deficits in social interaction and communication, restricted interests, stereotyped responses, and other repetitive patterns of behavior. Other abnormalities include mental retardation and comorbid epilepsy. These symptoms underscore the consequences of genetic inheritance for brain function and behavior. The etiology of autism may involve an interaction between genetic susceptibility (mediated by multiple genes) and environmental factors influencing brain development.
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Fisch GS. Syndromes and epistemology II: Is autism a polygenic disorder? Am J Med Genet A 2008; 146A:2203-12. [DOI: 10.1002/ajmg.a.32438] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Abu-Elneel K, Liu T, Gazzaniga FS, Nishimura Y, Wall DP, Geschwind DH, Lao K, Kosik KS. Heterogeneous dysregulation of microRNAs across the autism spectrum. Neurogenetics 2008; 9:153-61. [PMID: 18563458 DOI: 10.1007/s10048-008-0133-5] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 04/24/2008] [Indexed: 11/24/2022]
Abstract
microRNAs (miRNAs) are approximately 21 nt transcripts capable of regulating the expression of many mRNAs and are abundant in the brain. miRNAs have a role in several complex diseases including cancer as well as some neurological diseases such as Tourette's syndrome and Fragile x syndrome. As a genetically complex disease, dysregulation of miRNA expression might be a feature of autism spectrum disorders (ASDs). Using multiplex quantitative polymerase chain reaction (PCR), we compared the expression of 466 human miRNAs from postmortem cerebellar cortex tissue of individuals with ASD (n = 13) and a control set of non-autistic cerebellar samples (n = 13). While most miRNAs levels showed little variation across all samples suggesting that autism does not induce global dysfunction of miRNA expression, some miRNAs among the autistic samples were expressed at significantly different levels compared to the mean control value. Twenty-eight miRNAs were expressed at significantly different levels compared to the non-autism control set in at least one of the autism samples. To validate the finding, we reversed the analysis and compared each non-autism control to a single mean value for each miRNA across all autism cases. In this analysis, the number of dysregulated miRNAs fell from 28 to 9 miRNAs. Among the predicted targets of dysregulated miRNAs are genes that are known genetic causes of autism such Neurexin and SHANK3. This study finds that altered miRNA expression levels are observed in postmortem cerebellar cortex from autism patients, a finding which suggests that dysregulation of miRNAs may contribute to autism spectrum phenotype.
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Affiliation(s)
- Kawther Abu-Elneel
- Neuroscience Research Institute, Department of Molecular Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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