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Chien WH, Chen CH, Cheng MC, Wu YY, Gau SSF. Neuregulin 2 Is a Candidate Gene for Autism Spectrum Disorder. Int J Mol Sci 2024; 25:5547. [PMID: 38791584 PMCID: PMC11121989 DOI: 10.3390/ijms25105547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/04/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with heterogeneous and complex genetic underpinnings. Our previous microarray gene expression profiling identified significantly different neuregulin-2 gene (NRG2) expression between ASD patients and controls. Thus, we aimed to clarify whether NRG2 is a candidate gene associated with ASD. The study consisted of two stages. First, we used real-time quantitative PCR in 20 ASDs and 20 controls to confirm the microarray gene expression profiling results. The average NRG2 gene expression level in patients with ASD (3.23 ± 2.80) was significantly lower than that in the controls (9.27 ± 4.78, p < 0.001). Next, we conducted resequencing of all the exons of NRG2 in a sample of 349 individuals with ASD, aiming to identify variants of the NRG2 associated with ASD. We identified three variants, including two single nucleotide variants (SNVs), IVS3 + 13A > G (rs889022) and IVS10 + 32T > A (rs182642591), and one small deletion at exon 11 of NRG2 (delGCCCGG, rs933769137). Using data from the Taiwan Biobank as the controls, we found no significant differences in allele frequencies of rs889022 and rs182642591 between two groups. However, there is a significant difference in the genotype and allele frequency distribution of rs933769137 between ASDs and controls (p < 0.0001). The small deletion is located in the EGF-like domain at the C-terminal of the NRG2 precursor protein. Our findings suggest that NRG2 might be a susceptibility gene for ASD.
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Affiliation(s)
- Wei-Hsien Chien
- Department of Occupational Therapy, College of Medicine, Fu Jen Catholic University, New Taipei City 242062, Taiwan
| | - Chia-Hsiang Chen
- Department of Psychiatry, Linkou Chang Gung Memorial Hospital, Taoyuan 333, Taiwan; (C.-H.C.); (Y.-Y.W.)
| | - Min-Chih Cheng
- Department of Psychiatry, Yuli Branch, Taipei Veterans General Hospital, Hualien 981, Taiwan;
| | - Yu-Yu Wu
- Department of Psychiatry, Linkou Chang Gung Memorial Hospital, Taoyuan 333, Taiwan; (C.-H.C.); (Y.-Y.W.)
| | - Susan Shur-Fen Gau
- Department of Psychiatry, National Taiwan University Hospital, Taipei 10002, Taiwan
- Graduate Institute of Brain and Mind Sciences and Graduate of Clinical Medicine, National Taiwan University, Taipei 10002, Taiwan
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Mpoulimari I, Zintzaras E. Analysis of convergence of linkage and association studies in autism spectrum disorders. Psychiatr Genet 2023; 33:113-124. [PMID: 37212558 DOI: 10.1097/ypg.0000000000000341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of pervasive neurodevelopmental disorders with a strong hereditary component. Although genome-wide linkage studies (GWLS) and [genome-wide association studies (GWAS)] have previously identified hundreds of ASD risk gene loci, the results remain inconclusive. In this study, a genomic convergence approach of GWAS and GWLS for ASD was implemented for the first time in order to identify genomic loci supported by both methods. A database with 32 GWLS and five GWAS for ASD was created. Convergence was quantified as the proportion of significant GWAS markers located within linked regions. Convergence was not found to be significantly higher than expected by chance (z-test = 1,177, P = 0,239). Although convergence is supportive of genuine effects, the lack of agreement between GWLS and GWAS is also indicative that these studies are designed to answer different questions and are not equally well suited for deciphering the genetics of complex traits.
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Affiliation(s)
- Ioanna Mpoulimari
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Elias Zintzaras
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece
- The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
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3
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Mpoulimari I, Zintzaras E. Identification of Chromosomal Regions Linked to Autism-Spectrum Disorders: A Meta-Analysis of Genome-Wide Linkage Scans. Genet Test Mol Biomarkers 2022; 26:59-69. [PMID: 35225680 DOI: 10.1089/gtmb.2021.0236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Background: Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of pervasive neurodevelopmental disorders with a strong hereditary component. Although, genome-wide linkage scans (GWLS) and association studies (GWAS) have previously identified hundreds of ASD risk gene loci, the results remain inconclusive. Method: We performed a heterogeneity-based genome search meta-analysis (HEGESMA) of 15 genome scans of autism and ASD. Results: For strictly defined autism, data were analyzed across six separate genome scans. Region 7q22-q34 reached statistical significance in both weighted and unweighted analyses, with evidence of significantly low between-scan heterogeneity. For ASDs (data from 12 separate scans), chromosomal regions 5p15.33-5p15.1 and 15q22.32-15q26.1 reached significance in both weighted and unweighted analyses but did not reach significance for either low or high heterogeneity. Region 1q23.2-1q31.1 was significant in unweighted analyses with low between-scan heterogeneity. Finally, region 8p21.1-8q13.2 reached significant linkage peak in all our meta-analyses. When we combined all available genome scans (15), the same results were produced. Conclusions: This meta-analysis suggests that these regions should be further investigated for autism susceptibility genes, with the caveat that autism spectrum disorders have different linkage signals across genome scans, possibly because of the high genetic heterogeneity of the disease.
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Affiliation(s)
- Ioanna Mpoulimari
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Elias Zintzaras
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece.,The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
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Bühler A, Carl M. Zebrafish Tools for Deciphering Habenular Network-Linked Mental Disorders. Biomolecules 2021; 11:biom11020324. [PMID: 33672636 PMCID: PMC7924194 DOI: 10.3390/biom11020324] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 11/23/2022] Open
Abstract
Simple Summary Everything that we think, feel or do depends on the function of neural networks in the brain. These are highly complex structures made of cells (neurons) and their interconnections (axons), which develop dependent on precisely coordinated interactions of genes. Any gene mutation can result in unwanted alterations in neural network formation and concomitant brain disorders. The habenula neural network is one of these important circuits, which has been linked to autism, schizophrenia, depression and bipolar disorder. Studies using the zebrafish have uncovered genes involved in the development of this network. Intriguingly, some of these genes have also been identified as risk genes of human brain disorders highlighting the power of this animal model to link risk genes and the affected network to human disease. But can we use the advantages of this model to identify new targets and compounds with ameliorating effects on brain dysfunction? In this review, we summarise the current knowledge on techniques to manipulate the habenula neural network to study the consequences on behavior. Moreover, we give an overview of existing behavioral test to mimic aspects of mental disorders and critically discuss the applicability of the zebrafish model in this field of research. Abstract The prevalence of patients suffering from mental disorders is substantially increasing in recent years and represents a major burden to society. The underlying causes and neuronal circuits affected are complex and difficult to unravel. Frequent disorders such as depression, schizophrenia, autism, and bipolar disorder share links to the habenular neural circuit. This conserved neurotransmitter system relays cognitive information between different brain areas steering behaviors ranging from fear and anxiety to reward, sleep, and social behaviors. Advances in the field using the zebrafish model organism have uncovered major genetic mechanisms underlying the formation of the habenular neural circuit. Some of the identified genes involved in regulating Wnt/beta-catenin signaling have previously been suggested as risk genes of human mental disorders. Hence, these studies on habenular genetics contribute to a better understanding of brain diseases. We are here summarizing how the gained knowledge on the mechanisms underlying habenular neural circuit development can be used to introduce defined manipulations into the system to study the functional behavioral consequences. We further give an overview of existing behavior assays to address phenotypes related to mental disorders and critically discuss the power but also the limits of the zebrafish model for identifying suitable targets to develop therapies.
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Affiliation(s)
- Anja Bühler
- Correspondence: (A.B.); (M.C.); Tel.: +39-0461-282745 (A.B.); +39-0461-283931 (M.C.)
| | - Matthias Carl
- Correspondence: (A.B.); (M.C.); Tel.: +39-0461-282745 (A.B.); +39-0461-283931 (M.C.)
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López-Tobón A, Trattaro S, Testa G. The sociability spectrum: evidence from reciprocal genetic copy number variations. Mol Autism 2020; 11:50. [PMID: 32546261 PMCID: PMC7298749 DOI: 10.1186/s13229-020-00347-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/11/2020] [Indexed: 02/14/2023] Open
Abstract
Sociability entails some of the most complex behaviors processed by the central nervous system. It includes the detection, integration, and interpretation of social cues and elaboration of context-specific responses that are quintessentially species-specific. There is an ever-growing accumulation of molecular associations to autism spectrum disorders (ASD), from causative genes to endophenotypes across multiple functional layers; these however, have rarely been put in context with the opposite manifestation featured in hypersociability syndromes. Genetic copy number variations (CNVs) allow to investigate the relationships between gene dosage and its corresponding phenotypes. In particular, CNVs of the 7q11.23 locus, which manifest diametrically opposite social behaviors, offer a privileged window to look into the molecular substrates underlying the developmental trajectories of the social brain. As by definition sociability is studied in humans postnatally, the developmental fluctuations causing social impairments have thus far remained a black box. Here, we review key evidence of molecular players involved at both ends of the sociability spectrum, focusing on genetic and functional associations of neuroendocrine regulators and synaptic transmission pathways. We then proceed to propose the existence of a molecular axis centered around the paradigmatic dosage imbalances at the 7q11.23 locus, regulating networks responsible for the development of social behavior in humans and highlight the key role that neurodevelopmental models from reprogrammed pluripotent cells will play for its understanding.
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Affiliation(s)
- Alejandro López-Tobón
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, Milan, Italy.
- Department of Oncology and Hemato-oncology, Università degli studi di Milano, Milan, Italy.
| | - Sebastiano Trattaro
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, Milan, Italy.
- Department of Oncology and Hemato-oncology, Università degli studi di Milano, Milan, Italy.
| | - Giuseppe Testa
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, Milan, Italy.
- Department of Oncology and Hemato-oncology, Università degli studi di Milano, Milan, Italy.
- Human Technopole, Via Cristina Belgioioso 171, Milan, Italy.
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Patak J, Zhang-James Y, Faraone SV. Endosomal system genetics and autism spectrum disorders: A literature review. Neurosci Biobehav Rev 2016; 65:95-112. [PMID: 27048963 PMCID: PMC4866511 DOI: 10.1016/j.neubiorev.2016.03.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/25/2016] [Accepted: 03/27/2016] [Indexed: 01/01/2023]
Abstract
Autism spectrum disorders (ASDs) are a group of debilitating neurodevelopmental disorders thought to have genetic etiology, due to their high heritability. The endosomal system has become increasingly implicated in ASD pathophysiology. In an attempt to summarize the association between endosomal system genes and ASDs we performed a systematic review of the literature. We searched PubMed for relevant articles. Simons Foundation Autism Research Initiative (SFARI) gene database was used to exclude articles regarding genes with less than minimal evidence for association with ASDs. Our search retained 55 articles reviewed in two categories: genes that regulate and genes that are regulated by the endosomal system. Our review shows that the endosomal system is a novel pathway implicated in ASDs as well as other neuropsychiatric disorders. It plays a central role in aspects of cellular physiology on which neurons and glial cells are particularly reliant, due to their unique metabolic and functional demands. The system shows potential for biomarkers and pharmacological intervention and thus more research into this pathway is warranted.
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Affiliation(s)
- Jameson Patak
- Dept. of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, United States.
| | - Yanli Zhang-James
- Dept of Psychiatry, Upstate Medical University, Syracuse, NY, United States.
| | - Stephen V Faraone
- Dept. of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, United States; Dept of Psychiatry, Upstate Medical University, Syracuse, NY, United States; K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway.
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7
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Kohane IS. An autism case history to review the systematic analysis of large-scale data to refine the diagnosis and treatment of neuropsychiatric disorders. Biol Psychiatry 2015; 77:59-65. [PMID: 25034947 PMCID: PMC4260993 DOI: 10.1016/j.biopsych.2014.05.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/05/2014] [Accepted: 05/22/2014] [Indexed: 01/18/2023]
Abstract
Analysis of large-scale systems of biomedical data provides a perspective on neuropsychiatric disease that may be otherwise elusive. Described here is an analysis of three large-scale systems of data from autism spectrum disorder (ASD) and of ASD research as an exemplar of what might be achieved from study of such data. First is the biomedical literature that highlights the fact that there are two very successful but quite separate research communities and findings pertaining to genetics and the molecular biology of ASD. There are those studies positing ASD causes that are related to immunological dysregulation and those related to disorders of synaptic function and neuronal connectivity. Second is the emerging use of electronic health record systems and other large clinical databases that allow the data acquired during the course of care to be used to identify distinct subpopulations, clinical trajectories, and pathophysiological substructures of ASD. These systems reveal subsets of patients with distinct clinical trajectories, some of which are immunologically related and others which follow pathologies conventionally thought of as neurological. The third is genome-wide genomic and transcriptomic analyses which show molecular pathways that overlap neurological and immunological mechanisms. The convergence of these three large-scale data perspectives illustrates the scientific leverage that large-scale data analyses can provide in guiding researchers in an approach to the diagnosis of neuropsychiatric disease that is inclusive and comprehensive.
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Affiliation(s)
- Isaac S Kohane
- Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts.
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8
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Brief Report: Phenotypic Differences and their Relationship to Paternal Age and Gender in Autism Spectrum Disorder. J Autism Dev Disord 2014; 45:1915-24. [PMID: 25526953 DOI: 10.1007/s10803-014-2346-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Two modes of inheritance have been proposed in autism spectrum disorder, transmission though pre-existing variants and de novo mutations. Different modes may lead to different symptom expressions in affected individuals. De novo mutations become more likely with advancing paternal age suggesting that paternal age may predict phenotypic differences. To test this possibility we measured IQ, adaptive behavior, and autistic symptoms in 830 probands from simplex families. We conducted multiple linear regression analysis to estimate the predictive value of paternal age, maternal age, and gender on behavioral measures and IQ. We found a differential effect of parental age and sex on repetitive and restricted behaviors. Findings suggest effects of paternal age on phenotypic differences in simplex families with ASD.
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9
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Uzunova G, Hollander E, Shepherd J. The role of ionotropic glutamate receptors in childhood neurodevelopmental disorders: autism spectrum disorders and fragile x syndrome. Curr Neuropharmacol 2014; 12:71-98. [PMID: 24533017 PMCID: PMC3915351 DOI: 10.2174/1570159x113116660046] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/20/2013] [Accepted: 09/25/2013] [Indexed: 12/20/2022] Open
Abstract
Autism spectrum disorder (ASD) and Fragile X syndrome (FXS) are relatively common childhood neurodevelopmental disorders with increasing incidence in recent years. They are currently accepted as disorders of the synapse with alterations in different forms of synaptic communication and neuronal network connectivity. The major excitatory neurotransmitter system in brain, the glutamatergic system, is implicated in learning and memory, synaptic plasticity, neuronal development. While much attention is attributed to the role of metabotropic glutamate receptors in ASD and FXS, studies indicate that the ionotropic glutamate receptors (iGluRs) and their regulatory proteins are also altered in several brain regions. Role of iGluRs in the neurobiology of ASD and FXS is supported by a weight of evidence that ranges from human genetics to in vitro cultured neurons. In this review we will discuss clinical, molecular, cellular and functional changes in NMDA, AMPA and kainate receptors and the synaptic proteins that regulate them in the context of ASD and FXS. We will also discuss the significance for the development of translational biomarkers and treatments for the core symptoms of ASD and FXS.
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Affiliation(s)
- Genoveva Uzunova
- Autism and Obsessive Compulsive Spectrum Program, Department of Psychiatry, Montefiore Medical Center, Albert Einstein College of Medicine, 111 East 210th St, Bronx, New York 10467-2490
| | - Eric Hollander
- Autism and Obsessive Compulsive Spectrum Program, Department of Psychiatry, Montefiore Medical Center, Albert Einstein College of Medicine, 111 East 210th St, Bronx, New York 10467-2490
| | - Jason Shepherd
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, 531A Wintrobe, 20N 1900 E, Salt Lake City, Utah 84132
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10
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Glutamatergic candidate genes in autism spectrum disorder: an overview. J Neural Transm (Vienna) 2014; 121:1081-106. [PMID: 24493018 DOI: 10.1007/s00702-014-1161-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/13/2014] [Indexed: 12/22/2022]
Abstract
Autism spectrum disorders (ASD) are neurodevelopmental disorders with early onset in childhood. Most of the risk for ASD can be explained by genetic variants that act in interaction with biological environmental risk factors. However, the architecture of the genetic components is still unclear. Genetic studies and subsequent systems biological approaches described converging functional effects of identified genes towards pathways relevant for neuronal signalling. Mouse models suggest an aberrant synaptic plasticity at the neuropathological level, which is believed to be conferred by dysregulation of long-term potentiation or depression of neuronal connections. A central pathway regulating these mechanisms is glutamatergic signalling. Here, we hypothesized that susceptibility genes for ASD are enriched for components of this pathway. To further understand the impact of ASD risk genes on the glutamatergic pathway, we performed a systematic review using the literature database "pubmed" and the "AutismKB" knowledgebase. We provide an overview of the glutamatergic system in typical brain function and development, and summarize findings from linkage, association, copy number variants, and sequencing studies in ASD to provide a comprehensive picture of the glutamatergic landscape of ASD genetics. Genetic variants associated with ASD were enriched in glutamatergic pathways, affecting receptor signalling, metabolism and transport. Furthermore, in genetically modified mouse models for ASD, pharmacological compounds acting on ionotropic or metabotropic receptor activity are able to rescue ASD reminscent phenotypes. We conclude that glutamatergic genetic risk factors for ASD show a complex pattern and further studies are needed to fully understand its mechanisms, before translation of findings into clinical applications and individualized treatment approaches will be possible.
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Talebizadeh Z, Arking DE, Hu VW. A Novel Stratification Method in Linkage Studies to Address Inter- and Intra-Family Heterogeneity in Autism. PLoS One 2013; 8:e67569. [PMID: 23840741 PMCID: PMC3694043 DOI: 10.1371/journal.pone.0067569] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/20/2013] [Indexed: 12/21/2022] Open
Abstract
Most genome linkage scans for autism spectrum disorders (ASDs) have failed to be replicated. Recently, a new ASD phenotypic sub-classification method was developed which employed cluster analyses of severity scores from the Autism Diagnostic Interview-Revised (ADI-R). Here, we performed linkage analysis for each of the four identified ADI-R stratified subgroups. Additional stratification was also applied to reduce intra-family heterogeneity and to investigate the impact of gender. For the purpose of replication, two independent sets of single nucleotide polymorphism markers for 392 families were used in our study. This deep subject stratification protocol resulted in 16 distinct group-specific datasets for linkage analysis. No locus reached significance for the combined non-stratified cohort. However, study-wide significant (P = 0.02) linkage scores were reached for chromosomes 22q11 (LOD = 4.43) and 13q21 (LOD = 4.37) for two subsets representing the most severely language impaired individuals with ASD. Notably, 13q21 has been previously linked to autism with language impairment, and 22q11 has been separately associated with either autism or language disorders. Linkage analysis on chromosome 5p15 for a combination of two stratified female-containing subgroups demonstrated suggestive linkage (LOD = 3.5), which replicates previous linkage result for female-containing pedigrees. A trend was also found for the association of previously reported 5p14-p15 SNPs in the same female-containing cohort. This study demonstrates a novel and effective method to address the heterogeneity in genetic studies of ASD. Moreover, the linkage results for the stratified subgroups provide evidence at the gene scan level for both inter- and intra-family heterogeneity as well as for gender-specific loci.
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Affiliation(s)
- Zohreh Talebizadeh
- Medical Genetics Research, Children’s Mercy Hospitals and Clinics and University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, United States of America
- * E-mail:
| | - Dan E. Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valerie W. Hu
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, United States of America
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Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition that results in behavioral, social and communication impairments. ASD has a substantial genetic component, with 88-95% trait concordance among monozygotic twins. Efforts to elucidate the causes of ASD have uncovered hundreds of susceptibility loci and candidate genes. However, owing to its polygenic nature and clinical heterogeneity, only a few of these markers represent clear targets for further analyses. In the present study, we used the linkage structure associated with published genetic markers of ASD to simultaneously improve candidate gene detection while providing a means of prioritizing markers of common genetic variation in ASD. We first mined the literature for linkage and association studies of single-nucleotide polymorphisms, copy-number variations and multi-allelic markers in Autism Genetic Resource Exchange (AGRE) families. From markers that reached genome-wide significance, we calculated male-specific genetic distances, in light of the observed strong male bias in ASD. Four of 67 autism-implicated regions, 3p26.1, 3p26.3, 3q25-27 and 5p15, were enriched with differentially expressed genes in blood and brain from individuals with ASD. Of 30 genes differentially expressed across multiple expression data sets, 21 were within 10 cM of an autism-implicated locus. Among them, CNTN4, CADPS2, SUMF1, SLC9A9, NTRK3 have been previously implicated in autism, whereas others have been implicated in neurological disorders comorbid with ASD. This work leverages the rich multimodal genomic information collected on AGRE families to present an efficient integrative strategy for prioritizing autism candidates and improving our understanding of the relationships among the vast collection of past genetic studies.
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Marchani EE, Chapman NH, Cheung CYK, Ankenman K, Stanaway IB, Coon HH, Nickerson D, Bernier R, Brkanac Z, Wijsman EM. Identification of rare variants from exome sequence in a large pedigree with autism. Hum Hered 2013; 74:153-64. [PMID: 23594493 DOI: 10.1159/000346560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We carried out analyses with the goal of identifying rare variants in exome sequence data that contribute to disease risk for a complex trait. We analyzed a large, 47-member, multigenerational pedigree with 11 cases of autism spectrum disorder, using genotypes from 3 technologies representing increasing resolution: a multiallelic linkage marker panel, a dense diallelic marker panel, and variants from exome sequencing. Genome-scan marker genotypes were available on most subjects, and exome sequence data was available on 5 subjects. We used genome-scan linkage analysis to identify and prioritize the chromosome 22 region of interest, and to select subjects for exome sequencing. Inheritance vectors (IVs) generated by Markov chain Monte Carlo analysis of multilocus marker data were the foundation of most analyses. Genotype imputation used IVs to determine which sequence variants reside on the haplotype that co-segregates with the autism diagnosis. Together with a rare-allele frequency filter, we identified only one rare variant on the risk haplotype, illustrating the potential of this approach to prioritize variants. The associated gene, MYH9, is biologically unlikely, and we speculate that for this complex trait, the key variants may lie outside the exome.
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Affiliation(s)
- E E Marchani
- Division of Medical Genetics, University of Washington, Seattle, WA 98195, USA
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Kalkman HO. A review of the evidence for the canonical Wnt pathway in autism spectrum disorders. Mol Autism 2012; 3:10. [PMID: 23083465 PMCID: PMC3492093 DOI: 10.1186/2040-2392-3-10] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/04/2012] [Indexed: 12/21/2022] Open
Abstract
Microdeletion and microduplication copy number variations are found in patients with autism spectrum disorder and in a number of cases they include genes that are involved in the canonical Wnt signaling pathway (for example, FZD9, BCL9 or CDH8). Association studies investigating WNT2, DISC1, MET, DOCK4 or AHI1 also provide evidence that the canonical Wnt pathway might be affected in autism. Prenatal medication with sodium-valproate or antidepressant drugs increases autism risk. In animal studies, it has been found that these medications promote Wnt signaling, including among others an increase in Wnt2 gene expression. Notably, the available genetic information indicates that not only canonical Wnt pathway activation, but also inhibition seems to increase autism risk. The canonical Wnt pathway plays a role in dendrite growth and suboptimal activity negatively affects the dendritic arbor. In principle, this provides a logical explanation as to why both hypo- and hyperactivity may generate a similar set of behavioral and cognitive symptoms. However, without a validated biomarker to stratify for deviant canonical Wnt pathway activity, it is probably too dangerous to treat patients with compounds that modify pathway activity.
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Affiliation(s)
- Hans Otto Kalkman
- Neuroscience Department, Novartis Institute of Biomedical Research, Building 386-14,22,15, Basel, CH 4002, Switzerland.
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15
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Li X, Zou H, Brown WT. Genes associated with autism spectrum disorder. Brain Res Bull 2012; 88:543-52. [PMID: 22688012 DOI: 10.1016/j.brainresbull.2012.05.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 05/31/2012] [Indexed: 01/06/2023]
Abstract
Autism spectrum disorder (ASD) is a heterogeneous grouping of neurodevelopmental disorders characterized by impairment in social interaction, verbal communication and repetitive/stereotypic behaviors. Much evidence suggests that ASD is multifactorial with a strong genetic basis, but the underlying mechanisms are far from clear. Recent advances in genetic technologies are beginning to shed light on possible etiologies of ASD. This review discusses current evidence for several widely studied candidate ASD genes, as well as various rare genes that supports their relationship to the etiology of ASD. The majority of the data are based on molecular, cytogenetic, linkage and association studies of autistic subjects, but newer methods, including whole-exome sequencing, are also beginning to make significant contributions to our understanding of autism.
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Affiliation(s)
- Xiaohong Li
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, New York, NY 10314, United States.
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Freitag CM, Asherson P, Hebebrand J. Behavioural genetics of childhood disorders. Curr Top Behav Neurosci 2012; 12:395-428. [PMID: 22382729 DOI: 10.1007/7854_2011_178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
After a general introduction into genetic risk factors for child psychiatric disorders, four specific child psychiatric disorders with a strong genetic component, namely, Autism Spectrum Disorders, Attention Deficit / Hyperactivity Disorder, Nocturnal Enuresis, and obesity, are discussed in detail. Recent evidence of linkage, candidate gene, and genome-wide association studies are presented. This chapter ends with a prospectus on further research needs.
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Affiliation(s)
- Christine M Freitag
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe-Universität Frankfurt am Main, Deutschordenstraße 50, 60528, Frankfurt am Main, Germany,
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Puleo CM, Schmeidler J, Reichenberg A, Kolevzon A, Soorya LV, Buxbaum JD, Silverman JM. Advancing paternal age and simplex autism. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2011; 16:367-80. [PMID: 22180389 DOI: 10.1177/1362361311427154] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
De novo events appear more common in female and simplex autism spectrum disorder (ASD) cases and may underlie greater ASD risk in older fathers' offspring. This study examined whether advancing paternal age predicts an increase in simplex (n = 90) versus multiplex ASD cases (n = 587) in 677 participants (340 families). Whether or not controlling for maternal age, results support a significant interaction of linear paternal age and sex of the child on simplex family type. Female ASD cases were significantly more likely to be simplex as paternal age increased, but the increase for males was not significant. Findings suggest that ASD arising from non-familial, de novo events may be far less prominent in males than in females, even if more prevalent in males, due to the substantially larger number of male cases attributable to other, more strongly male-biased risk factors.
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Developing a Deeper Understanding of Autism: Connecting Knowledge through Literature Mining. AUTISM RESEARCH AND TREATMENT 2011; 2011:307152. [PMID: 22937244 PMCID: PMC3420468 DOI: 10.1155/2011/307152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 04/13/2011] [Indexed: 02/07/2023]
Abstract
In the field of autism, an enormous increase in available information makes it very difficult to connect fragments of knowledge into a more coherent picture. We present a literature mining method, RaJoLink, to search for matched themes in unrelated literature that may contribute to a better understanding of complex pathological conditions, such as autism. 214 full text articles on autism, published in PubMed, served as a source of data. Using ontology construction, we identified the main concepts of what is already known about autism. Then, the RaJoLink method, based on Swanson's ABC model, was used to reveal potentially interesting, but not yet investigated, connections between different concepts in research. Among the more interesting concepts identified with RaJoLink in our study were calcineurin and NF-kappaB. Both terms can be linked to neuro-immune abnormalities in the brain of patients with autism. Further research is needed to provide stronger evidence about calcineurin and NF-kappaB involvement in autism. However, the analysis presented confirms that this method could support experts on their way towards discovering hidden relationships and towards a better understanding of the disorder.
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Gain-of-function glutamate receptor interacting protein 1 variants alter GluA2 recycling and surface distribution in patients with autism. Proc Natl Acad Sci U S A 2011; 108:4920-5. [PMID: 21383172 DOI: 10.1073/pnas.1102233108] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glutamate receptor interacting protein 1 (GRIP1) is a neuronal scaffolding protein that interacts directly with the C termini of glutamate receptors 2/3 (GluA2/3) via its PDZ domains 4 to 6 (PDZ4-6). We found an association (P<0.05) of a SNP within the PDZ4-6 genomic region with autism by genotyping autistic patients (n=480) and matched controls (n=480). Parallel sequencing identified five rare missense variants within or near PDZ4-6 only in the autism cohort, resulting in a higher cumulative mutation load (P=0.032). Two variants correlated with a more severe deficit in reciprocal social interaction in affected sibling pairs from proband families. These variants were associated with altered interactions with GluA2/3 and faster recycling and increased surface distribution of GluA2 in neurons, suggesting gain-of-function because GRIP1/2 deficiency showed opposite phenotypes. Grip1/2 knockout mice exhibited increased sociability and impaired prepulse inhibition. These results support a role for GRIP in social behavior and implicate GRIP1 variants in modulating autistic phenotype.
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20
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Myers RA, Casals F, Gauthier J, Hamdan FF, Keebler J, Boyko AR, Bustamante CD, Piton AM, Spiegelman D, Henrion E, Zilversmit M, Hussin J, Quinlan J, Yang Y, Lafrenière RG, Griffing AR, Stone EA, Rouleau GA, Awadalla P. A population genetic approach to mapping neurological disorder genes using deep resequencing. PLoS Genet 2011; 7:e1001318. [PMID: 21383861 PMCID: PMC3044677 DOI: 10.1371/journal.pgen.1001318] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 01/24/2011] [Indexed: 01/15/2023] Open
Abstract
Deep resequencing of functional regions in human genomes is key to identifying potentially causal rare variants for complex disorders. Here, we present the results from a large-sample resequencing (n = 285 patients) study of candidate genes coupled with population genetics and statistical methods to identify rare variants associated with Autism Spectrum Disorder and Schizophrenia. Three genes, MAP1A, GRIN2B, and CACNA1F, were consistently identified by different methods as having significant excess of rare missense mutations in either one or both disease cohorts. In a broader context, we also found that the overall site frequency spectrum of variation in these cases is best explained by population models of both selection and complex demography rather than neutral models or models accounting for complex demography alone. Mutations in the three disease-associated genes explained much of the difference in the overall site frequency spectrum among the cases versus controls. This study demonstrates that genes associated with complex disorders can be mapped using resequencing and analytical methods with sample sizes far smaller than those required by genome-wide association studies. Additionally, our findings support the hypothesis that rare mutations account for a proportion of the phenotypic variance of these complex disorders. It is widely accepted that genetic factors play important roles in the etiology of neurological diseases. However, the nature of the underlying genetic variation remains unclear. Critical questions in the field of human genetics relate to the frequency and size effects of genetic variants associated with disease. For instance, the common disease–common variant model is based on the idea that sets of common variants explain a significant fraction of the variance found in common disease phenotypes. On the other hand, rare variants may have strong effects and therefore largely contribute to disease phenotypes. Due to their high penetrance and reduced fitness, such variants are maintained in the population at low frequencies, thus limiting their detection in genome-wide association studies. Here, we use a resequencing approach on a cohort of 285 Autism Spectrum Disorder and Schizophrenia patients and preformed several analyses, enhanced with population genetic approaches, to identify variants associated with both diseases. Our results demonstrate an excess of rare variants in these disease cohorts and identify genes with negative (deleterious) selection coefficients, suggesting an accumulation of variants of detrimental effects. Our results present further evidence for rare variants explaining a component of the genetic etiology of autism and schizophrenia.
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Affiliation(s)
- Rachel A. Myers
- Department of Pediatrics, University of Montreal, Montreal, Canada
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, Canada
- Bioinformatics Research Centre, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ferran Casals
- Department of Pediatrics, University of Montreal, Montreal, Canada
| | - Julie Gauthier
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Fadi F. Hamdan
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Jon Keebler
- Department of Pediatrics, University of Montreal, Montreal, Canada
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, Canada
- Bioinformatics Research Centre, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Adam R. Boyko
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Carlos D. Bustamante
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Amelie M. Piton
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Dan Spiegelman
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Edouard Henrion
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | | | - Julie Hussin
- Department of Pediatrics, University of Montreal, Montreal, Canada
| | - Jacklyn Quinlan
- Department of Pediatrics, University of Montreal, Montreal, Canada
| | - Yan Yang
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Ronald G. Lafrenière
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
| | - Alexander R. Griffing
- Bioinformatics Research Centre, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Eric A. Stone
- Bioinformatics Research Centre, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Guy A. Rouleau
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, Canada
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
- * E-mail: (PA); (GAR)
| | - Philip Awadalla
- Department of Pediatrics, University of Montreal, Montreal, Canada
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, Canada
- Bioinformatics Research Centre, North Carolina State University, Raleigh, North Carolina, United States of America
- Centre of Excellence in Neuromics of Université de Montréal, Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Medicine, Université of Montréal, Montreal, Canada
- * E-mail: (PA); (GAR)
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21
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Tamiji J, Crawford DA. The neurobiology of lipid metabolism in autism spectrum disorders. Neurosignals 2011; 18:98-112. [PMID: 21346377 DOI: 10.1159/000323189] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 11/29/2010] [Indexed: 01/17/2023] Open
Abstract
Autism is a neurodevelopmental disorder characterized by impairments in communication and reciprocal social interaction, coupled with repetitive behavior, which typically manifests by 3 years of age. Multiple genes and early exposure to environmental factors are the etiological determinants of the disorder that contribute to variable expression of autism-related traits. Increasing evidence indicates that altered fatty acid metabolic pathways may affect proper function of the nervous system and contribute to autism spectrum disorders. This review provides an overview of the reported abnormalities associated with the synthesis of membrane fatty acids in individuals with autism as a result of insufficient dietary supplementation or genetic defects. Moreover, we discuss deficits associated with the release of arachidonic acid from the membrane phospholipids and its subsequent metabolism to bioactive prostaglandins via phospholipase A(2)-cyclooxygenase biosynthetic pathway in autism spectrum disorders. The existing evidence for the involvement of lipid neurobiology in the pathology of neurodevelopmental disorders such as autism is compelling and opens up an interesting possibility for further investigation of this metabolic pathway.
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Affiliation(s)
- Javaneh Tamiji
- Department of Biology, York University, Toronto, Ont., Canada
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22
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Strom SP, Stone JL, Bosch JRT, Merriman B, Cantor RM, Geschwind DH, Nelson SF. High-density SNP association study of the 17q21 chromosomal region linked to autism identifies CACNA1G as a novel candidate gene. Mol Psychiatry 2010; 15:996-1005. [PMID: 19455149 PMCID: PMC2889141 DOI: 10.1038/mp.2009.41] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chromosome 17q11-q21 is a region of the genome likely to harbor susceptibility to autism (MIM(209850)) based on earlier evidence of linkage to the disorder. This linkage is specific to multiplex pedigrees containing only male probands (MO) within the Autism Genetic Resource Exchange (AGRE). Earlier, Stone et al.(1) completed a high-density single nucleotide polymorphism association study of 13.7 Mb within this interval, but common variant association was not sufficient to account for the linkage signal. Here, we extend this single nucleotide polymorphism-based association study to complete the coverage of the two-LOD support interval around the chromosome 17q linkage peak by testing the majority of common alleles in 284 MO trios. Markers within an interval containing the gene, CACNA1G, were found to be associated with Autism Spectrum Disorder at a locally significant level (P=1.9 × 10(-5)). While establishing CACNA1G as a novel candidate gene for autism, these alleles do not contribute a sufficient genetic effect to explain the observed linkage, indicating that there is substantial genetic heterogeneity despite the clear linkage signal. The region thus likely harbors a combination of multiple common and rare alleles contributing to the genetic risk. These data, along with earlier studies of chromosomes 5 and 7q3, suggest few if any major common risk alleles account for Autism Spectrum Disorder risk under major linkage peaks in the AGRE sample. This provides important evidence for strategies to identify Autism Spectrum Disorder genes, suggesting that they should focus on identifying rare variants and common variants of small effect.
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Affiliation(s)
- Samuel P. Strom
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A
| | - Jennifer L. Stone
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A
| | - John R. ten Bosch
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A
| | - Barry Merriman
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A
| | - Rita M. Cantor
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A,Center for Neurobehavioral Genetics, University of California, Los Angeles, CA, U.S.A,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, U.S.A
| | - Daniel H. Geschwind
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A,Center for Neurobehavioral Genetics, University of California, Los Angeles, CA, U.S.A,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, U.S.A,Department of Neurology, University of California, Los Angeles, CA, U.S.A
| | - Stanley F. Nelson
- Department of Human Genetics, University of California, Los Angeles, CA, U.S.A,Center for Neurobehavioral Genetics, University of California, Los Angeles, CA, U.S.A,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, U.S.A,Corresponding Author Contact information: Stanley F. Nelson Phone: (310) 794 7981 Street Address: 695 Charles E. Young Drive South Gonda 5554 Los Angeles, CA 90095-7088
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23
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Yang SY, Cho SC, Yoo HJ, Cho IH, Park M, Kim BN, Kim JW, Shin MS, Park TW, Son JW, Chung US, Kim HW, Yang YH, Kang JO, Kim SA. Association study between single nucleotide polymorphisms in promoter region of AVPR1A and Korean autism spectrum disorders. Neurosci Lett 2010; 479:197-200. [PMID: 20546835 DOI: 10.1016/j.neulet.2010.05.050] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 04/22/2010] [Accepted: 05/13/2010] [Indexed: 12/20/2022]
Abstract
To determine the association between arginine vasopressin receptor 1A gene (AVPR1A) and autism spectrum disorders (ASDs), we examined 3 single nucleotide polymorphisms (SNPs), namely, rs7294536, rs3759292, and rs10877969, in the promoter region of AVPR1A by using a family-based association test (FBAT) in 151 Korean trios. Our results demonstrated a statistically significant association between autism and SNPs (additive model: rs7294536, chi(2)=9.328, df=2, P=0.002; rs10877969, chi(2)=11.529, df=2, P<0.001) as well as between autism and haplotype analysis (additive model: chi(2)=14.122, df=3, P=0.003). In addition, we found that ADI-R scores calculated by using a diagnostic algorithm for failure to develop peer relationships (A2) were higher in subjects having the AA genotype than in subjects having the AG and GG genotypes of rs7294536. Thus, our study provides evidence for a possible association between these SNPs and the phenotype of ASDs.
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Affiliation(s)
- So Young Yang
- Department of Pharmacology and Eulji University Medical Sciences Research Center, School of Medicine, Eulji University, 143-5 Yongdu-dong, Jung-gu, Daejeon 301-746, Republic of Korea
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24
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Genetics of autistic disorders: review and clinical implications. Eur Child Adolesc Psychiatry 2010; 19:169-78. [PMID: 19941018 PMCID: PMC2839494 DOI: 10.1007/s00787-009-0076-x] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 10/30/2009] [Indexed: 12/21/2022]
Abstract
Twin and family studies in autistic disorders (AD) have elucidated a high heritability of AD. In this literature review, we will present an overview on molecular genetic studies in AD and highlight the most recent findings of an increased rate of copy number variations in AD. An extensive literature search in the PubMed database was performed to obtain English published articles on genetic findings in autism. Results of linkage, (genome wide) association and cytogenetic studies are presented, and putative aetiopathological pathways are discussed. Implications of the different genetic findings for genetic counselling and genetic testing at present will be described. The article ends with a prospectus on future directions.
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25
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Morris CM, Zimmerman AW, Singer HS. Childhood serum anti-fetal brain antibodies do not predict autism. Pediatr Neurol 2009; 41:288-90. [PMID: 19748049 DOI: 10.1016/j.pediatrneurol.2009.04.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/09/2009] [Accepted: 04/13/2009] [Indexed: 10/20/2022]
Abstract
Autoimmune hypotheses for autism include in utero transplacental exposure to maternal antibodies and acquired postnatal insults. Previous work demonstrated that some mothers of children with autistic disorder have specific antibodies against human fetal brain that differentiate them from mothers with typical children. In the present study, Western immunoblotting was used to determine whether children with autistic spectrum disorders (n = 29) have serum reactivity against human fetal brain that differs from that of controls (n = 14). There was no significant difference in reactivity, corrected for serum immunoglobulin G content and brain actin content and with special attention to reactive bands at 36, 39, 61, and 73 kDa, between autistic children and normal control subjects. Thus, in contrast to mothers, antibody reactivity against human fetal brain as measured in children ages 3-12 years does not appear to be a useful biomarker for autism.
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Affiliation(s)
- Christina M Morris
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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26
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Ma D, Salyakina D, Jaworski JM, Konidari I, Whitehead PL, Andersen AN, Hoffman JD, Slifer SH, Hedges DJ, Cukier HN, Griswold AJ, McCauley JL, Beecham GW, Wright HH, Abramson RK, Martin ER, Hussman JP, Gilbert JR, Cuccaro ML, Haines JL, Pericak-Vance MA. A genome-wide association study of autism reveals a common novel risk locus at 5p14.1. Ann Hum Genet 2009; 73:263-73. [PMID: 19456320 DOI: 10.1111/j.1469-1809.2009.00523.x] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although autism is one of the most heritable neuropsychiatric disorders, its underlying genetic architecture has largely eluded description. To comprehensively examine the hypothesis that common variation is important in autism, we performed a genome-wide association study (GWAS) using a discovery dataset of 438 autistic Caucasian families and the Illumina Human 1M beadchip. 96 single nucleotide polymorphisms (SNPs) demonstrated strong association with autism risk (p-value < 0.0001). The validation of the top 96 SNPs was performed using an independent dataset of 487 Caucasian autism families genotyped on the 550K Illumina BeadChip. A novel region on chromosome 5p14.1 showed significance in both the discovery and validation datasets. Joint analysis of all SNPs in this region identified 8 SNPs having improved p-values (3.24E-04 to 3.40E-06) than in either dataset alone. Our findings demonstrate that in addition to multiple rare variations, part of the complex genetic architecture of autism involves common variation.
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Affiliation(s)
- Deqiong Ma
- Miami Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
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27
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Anello A, Reichenberg A, Luo X, Schmeidler J, Hollander E, Smith CJ, Puleo CM, Kryzak LA, Silverman JM. Brief report: parental age and the sex ratio in autism. J Autism Dev Disord 2009; 39:1487-92. [PMID: 19452267 DOI: 10.1007/s10803-009-0755-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 05/05/2009] [Indexed: 10/20/2022]
Abstract
The male-to-female (M:F) ratio for autism spectrum disorders (ASD), typically about 4:1, appears to decrease with increasing paternal age, but this relationship has not been systematically tested. With 393 ASD cases from families with two or more ASD cases, we categorized paternal age into five age groups (<30, 30-34, 35-39, 40-44, 45+) and found that the M:F ratio was significantly decreased with increasing paternal age groups and remained so after also adjusting for maternal age. No significant relationship between maternal age group and the M:F ratio was observed. This study suggests that the M:F ratio is reduced with increasing paternal age consistent with de novo genetic or genomic anomalies arising more frequently as men age and then conceive children.
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28
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Abstract
The cancer stem cell hypothesis posits that malignant growth arises from a rare population of progenitor cells within a tumor that provide it with unlimited regenerative capacity. Such cells also possess increased resistance to chemotherapeutic agents. Resurgence of chemoresistant disease after primary therapy typifies epithelial ovarian cancer and may be attributable to residual cancer stem cells, or cancer-initiating cells, that survive initial treatment. As the cell surface marker CD133 identifies cancer-initiating cells in a number of other malignancies, we sought to determine the potential role of CD133+ cells in epithelial ovarian cancer. We detected CD133 on ovarian cancer cell lines, in primary cancers and on purified epithelial cells from ascitic fluid of ovarian cancer patients. We found CD133+ ovarian cancer cells generate both CD133+ and CD133- daughter cells, whereas CD133- cells divide symmetrically. CD133+ cells exhibit enhanced resistance to platinum-based therapy, drugs commonly used as first-line agents for the treatment of ovarian cancer. Sorted CD133+ ovarian cancer cells also form more aggressive tumor xenografts at a lower inoculum than their CD133- progeny. Epigenetic changes may be integral to the behavior of cancer progenitor cells and their progeny. In this regard, we found that CD133 transcription is controlled by both histone modifications and promoter methylation. Sorted CD133- ovarian cancer cells treated with DNA methyltransferase and histone deacetylase inhibitors show a synergistic increase in cell surface CD133 expression. Moreover, DNA methylation at the ovarian tissue active P2 promoter is inversely correlated with CD133 transcription. We also found that promoter methylation increases in CD133- progeny of CD133+ cells, with CD133+ cells retaining a less methylated or unmethylated state. Taken together, our results show that CD133 expression in ovarian cancer is directly regulated by epigenetic modifications and support the idea that CD133 demarcates an ovarian cancer-initiating cell population. The activity of these cells may be epigenetically detected and such cells might serve as pertinent chemotherapeutic targets for reducing disease recurrence.
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Losh M, Sullivan PF, Trembath D, Piven J. Current developments in the genetics of autism: from phenome to genome. J Neuropathol Exp Neurol 2008; 67:829-37. [PMID: 18716561 PMCID: PMC2649757 DOI: 10.1097/nen.0b013e318184482d] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Despite compelling evidence from twin and family studies indicating a strong genetic involvement in the etiology of autism, the unequivocal detection of autism susceptibility genes remains an elusive goal. The purpose of this review is to evaluate the current state of autism genetics research, with attention focused on new techniques and analytic approaches. We first present a brief overview of evidence for the genetic basis of autism, followed by an appraisal of linkage and candidate gene study findings and consideration of new analytic approaches to the study of complex psychiatric conditions, namely, genome-wide association studies, assessment of structural variation within the genome, and the incorporation of endophenotypes in genetic analysis.
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Affiliation(s)
- Molly Losh
- Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7190, USA.
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30
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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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31
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Temperament and its Relationship to Autistic Symptoms in a High-Risk Infant Sib Cohort. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2008; 37:59-78. [DOI: 10.1007/s10802-008-9258-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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32
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Carney R, Slifer M, Lin P, Gaskell PC, Scott WK, Potocky C, Hulette CM, Welsh-Bohmer KA, Schmechel DE, Vance J, Pericak-Vance MA. Longitudinal follow-up of late-onset Alzheimer disease families. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:571-8. [PMID: 18361431 PMCID: PMC2713878 DOI: 10.1002/ajmg.b.30590] [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: 11/06/2022]
Abstract
Historically, data for genetic studies are collected at one time point. However, for diseases with late onset or with complex phenotypes, such as Alzheimer disease (AD), restricting diagnosis to a single ascertainment contact may not be sufficient. Affection status may change over time and some initial diagnoses may be inconclusive. Follow-up provides the opportunity to resolve these complications. However, to date, previous studies have not formally demonstrated that longitudinally re-contacting families is practical or productive. To update data initially collected for linkage analysis of late-onset Alzheimer disease (LOAD), we successfully re-contacted 63 of 81 (78%) multiplex families (two to 17 years after ascertainment). Clinical status changed for 73 of the 230 (32%) non-affected participants. Additionally, expanded family history identified 20 additional affected individuals to supplement the data set. Furthermore, fostering ongoing relationships with participating families helped recruit 101 affected participants into an autopsy and tissue donation program. Despite similar presentations, discordance between clinical diagnosis and neuropathologic diagnosis was observed in 28% of those with tissue diagnoses. Most of the families were successfully re-contacted, and significant refinement and supplementation of the data was achieved. We concluded that serial contact with longitudinal evaluation of families has significant implications for genetic analyses.
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Affiliation(s)
- R.M. Carney
- Duke University Medical Center, Durham, NC, 27710
| | - M.A. Slifer
- Duke University Medical Center, Durham, NC, 27710
| | - P.I. Lin
- Duke University Medical Center, Durham, NC, 27710
| | | | - W. K. Scott
- Miami Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33101
| | - C.F. Potocky
- Duke University Medical Center, Durham, NC, 27710
| | - C. M. Hulette
- Joseph and Kathleen Bryan Alzheimer Disease Research Center, Duke University Medical Center, Durham, NC, 27710
| | - K. A. Welsh-Bohmer
- Joseph and Kathleen Bryan Alzheimer Disease Research Center, Duke University Medical Center, Durham, NC, 27710
| | - D. E. Schmechel
- Department of Medicine and Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27710
| | - J.M. Vance
- Miami Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33101
| | - M. A. Pericak-Vance
- Miami Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33101
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Abrahams BS, Geschwind DH. Advances in autism genetics: on the threshold of a new neurobiology. Nat Rev Genet 2008; 9:341-55. [PMID: 18414403 DOI: 10.1038/nrg2346] [Citation(s) in RCA: 1150] [Impact Index Per Article: 71.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Autism is a heterogeneous syndrome defined by impairments in three core domains: social interaction, language and range of interests. Recent work has led to the identification of several autism susceptibility genes and an increased appreciation of the contribution of de novo and inherited copy number variation. Promising strategies are also being applied to identify common genetic risk variants. Systems biology approaches, including array-based expression profiling, are poised to provide additional insights into this group of disorders, in which heterogeneity, both genetic and phenotypic, is emerging as a dominant theme.
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Affiliation(s)
- Brett S Abrahams
- Neurology Department, and Semel Institute for Neuroscience and Behaviour, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095-1769 USA.
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Freitag CM. Genetik autistischer Störungen. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2008; 36:7-14; quiz 14-5. [DOI: 10.1024/1422-4917.36.1.7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Zusammenfassung: Autistische Störungen sind heterogene Erkrankungen. Die Betroffenen zeigen Einschränkungen der Kommunikation und sozialen Interaktion und stereotypes, repetitives Verhalten sowie Sonderinteressen. Der überwiegende Teil der autistischen Störungen sind genetisch bedingt. In dem Artikel wird eine Übersicht über zytogenetische Veränderungen sowie molekulargenetische Kopplungs- und Assoziationsstudien gegeben. Wichtige Differentialdiagnosen werden beschrieben. Die Ergebnisse dieser Studien haben eine besondere Bedeutung für die genetische Beratung der Familien.
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Affiliation(s)
- Christine M. Freitag
- Klinik für Kinder- und Jugendpsychiatrie, Universitätsklinikum des Saarlandes, Homburg
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Caldwell HK, Lee HJ, Macbeth AH, Young WS. Vasopressin: behavioral roles of an "original" neuropeptide. Prog Neurobiol 2007; 84:1-24. [PMID: 18053631 DOI: 10.1016/j.pneurobio.2007.10.007] [Citation(s) in RCA: 328] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 10/24/2007] [Accepted: 10/24/2007] [Indexed: 01/07/2023]
Abstract
Vasopressin (Avp) is mainly synthesized in the magnocellular cells of the hypothalamic supraoptic (SON) and paraventricular nuclei (PVN) whose axons project to the posterior pituitary. Avp is then released into the blood stream upon appropriate stimulation (e.g., hemorrhage or dehydration) to act at the kidneys and blood vessels. The brain also contains several populations of smaller, parvocellular neurons whose projections remain within the brain. These populations are located within the PVN, bed nucleus of the stria terminalis (BNST), medial amygdala (MeA) and suprachiasmatic nucleus (SCN). Since the 1950s, research examining the roles of Avp in the brain and periphery has intensified. The development of specific agonists and antagonists for Avp receptors has allowed for a better elucidation of its contributions to physiology and behavior. Anatomical, pharmacological and transgenic, including "knockout," animal studies have implicated Avp in the regulation of various social behaviors across species. Avp plays a prominent role in the regulation of aggression, generally of facilitating or promoting it. Affiliation and certain aspects of pair-bonding are also influenced by Avp. Memory, one of the first brain functions of Avp that was investigated, has been implicated especially strongly in social recognition. The roles of Avp in stress, anxiety, and depressive states are areas of active exploration. In this review, we concentrate on the scientific progress that has been made in understanding the role of Avp in regulating these and other behaviors across species. We also discuss the implications for human behavior.
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Affiliation(s)
- Heather K Caldwell
- Section on Neural Gene Expression, NIMH, NIH, DHHS, Bethesda, MD 20892, United States
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Skuse DH. Rethinking the nature of genetic vulnerability to autistic spectrum disorders. Trends Genet 2007; 23:387-95. [PMID: 17630015 DOI: 10.1016/j.tig.2007.06.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 05/24/2007] [Accepted: 06/22/2007] [Indexed: 12/28/2022]
Abstract
Autism is a common and genetically heterogeneous disorder, with an estimated heritability of >90%. Its specific underlying causes are largely unknown. Here, I propose that low levels of autistic vulnerability, reflected in social-cognitive processing differences, do not necessarily manifest in a behavioural phenotype but are usually compensated for during development. They are more likely to lead to a recognizable syndrome among individuals of low intelligence, who are male or have independent neurodevelopmental vulnerability owing to a wide range of gene mutations, chromosomal anomalies or environmental insults. Consequently, the apparent association between mental retardation and autistic syndromes is not because they usually have common causes, but rather because the presence of both features greatly increases the probability of clinical ascertainment.
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Affiliation(s)
- David H Skuse
- Behavioural and Brain Sciences Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
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