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Hong G, Fu X, Chen X, Zhang L, Han X, Ding S, Liu Z, Bi X, Li W, Chang M, Qiao R, Guo S, Tu H, Chai R. Dyslexia-Related Hearing Loss Occurs Mainly through the Abnormal Spontaneous Electrical Activity of Spiral Ganglion Neurons. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205754. [PMID: 37068190 DOI: 10.1002/advs.202205754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/25/2023] [Indexed: 06/04/2023]
Abstract
Dyslexia is a reading and spelling disorder due to neurodevelopmental abnormalities and is occasionally found to be accompanied by hearing loss, but the reason for the associated deafness remains unclear. This study finds that knockout of the dyslexia susceptibility 1 candidate 1 gene (Dyx1c1-/- ) in mice, the best gene for studying dyslexia, causes severe hearing loss, and thus it is a good model for studying the mechanism of dyslexia-related hearing loss (DRHL). This work finds that the Dyx1c1 gene is highly expressed in the mouse cochlea and that the spontaneous electrical activity of inner hair cells and type I spiral ganglion neurons is altered in the cochleae of Dyx1c1-/- mice. In addition, primary ciliary dyskinesia-related phenotypes such as situs inversus and disrupted ciliary structure are seen in Dyx1c1-/- mice. In conclusion, this study gives new insights into the mechanism of DRHL in detail and suggests that Dyx1c1 may serve as a potential target for the clinical diagnosis of DRHL.
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Affiliation(s)
- Guodong Hong
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Xiaolong Fu
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Xin Chen
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
| | - Liyan Zhang
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
| | - Xuan Han
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
| | - Shuqin Ding
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
| | - Ziyi Liu
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Xiuli Bi
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Wen Li
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Miao Chang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Ruifeng Qiao
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Siwei Guo
- School of Life Science, Shandong University, 266237, Qingdao, China
| | - Hailong Tu
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, 250000, Jinan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, 210096, Nanjing, China
- Co-Innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 610072, Chengdu, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Science, 100101, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, 100069, Beijing, China
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2
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Bieder A, Chandrasekar G, Wason A, Erkelenz S, Gopalakrishnan J, Kere J, Tapia-Páez I. Genetic and protein interaction studies between the ciliary dyslexia candidate genes DYX1C1 and DCDC2. BMC Mol Cell Biol 2023; 24:20. [PMID: 37237337 DOI: 10.1186/s12860-023-00483-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND DYX1C1 (DNAAF4) and DCDC2 are two of the most replicated dyslexia candidate genes in genetic studies. They both have demonstrated roles in neuronal migration, in cilia growth and function and they both are cytoskeletal interactors. In addition, they both have been characterized as ciliopathy genes. However, their exact molecular functions are still incompletely described. Based on these known roles, we asked whether DYX1C1 and DCDC2 interact on the genetic and the protein level. RESULTS Here, we report the physical protein-protein interaction of DYX1C1 and DCDC2 as well as their respective interactions with the centrosomal protein CPAP (CENPJ) on exogenous and endogenous levels in different cell models including brain organoids. In addition, we show a synergistic genetic interaction between dyx1c1 and dcdc2b in zebrafish exacerbating the ciliary phenotype. Finally, we show a mutual effect on transcriptional regulation among DYX1C1 and DCDC2 in a cellular model. CONCLUSIONS In summary, we describe the physical and functional interaction between the two genes DYX1C1 and DCDC2. These results contribute to the growing understanding of the molecular roles of DYX1C1 and DCDC2 and set the stage for future functional studies.
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Affiliation(s)
- Andrea Bieder
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | - Arpit Wason
- Center for Molecular Medicine, Institute for Biochemistry I of the University of Cologne, Cologne, Germany
| | - Steffen Erkelenz
- Institute of Human Genetics, Universitätsklinikum, Heinrich Heine University, Düsseldorf, Germany
| | - Jay Gopalakrishnan
- Institute of Human Genetics, Universitätsklinikum, Heinrich Heine University, Düsseldorf, Germany
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- Molecular Neurology Research Program, University of Helsinki, Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Isabel Tapia-Páez
- Department of Medicine, Solna, Karolinska Institutet, Solnavägen 30, SE-171 76, Solna, Sweden.
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3
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Kittock CM, Pilaz LJ. Advances in in utero electroporation. Dev Neurobiol 2023; 83:73-90. [PMID: 36861639 DOI: 10.1002/dneu.22910] [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: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023]
Abstract
In utero electroporation (IUE) is a technique developed in the early 2000s to transfect the neurons and neural progenitors of embryonic brains, thus enabling continued development in utero and subsequent analyses of neural development. Early IUE experiments focused on ectopic expression of plasmid DNA to analyze parameters such as neuron morphology and migration. Recent advances made in other fields, such as CRISPR/CAS9 genome editing, have been incorporated into IUE techniques as they were developed. Here, we provide a general review of the mechanics and techniques involved in IUE and explore the breadth of approaches that can be used in conjunction with IUE to study cortical development in a rodent model, with a focus on the novel advances in IUE techniques. We also highlight a few cases that exemplify the potential of IUE to study a broad range of questions in neural development.
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Affiliation(s)
- Claire M Kittock
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Louis-Jan Pilaz
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
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4
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Elsherif M, Mourad M, Hamouda N, Abdou R, Salem T. Diagnostic performance of a modified visual perception test. HEARING, BALANCE AND COMMUNICATION 2022. [DOI: 10.1080/21695717.2022.2155777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Mayada Elsherif
- Otolaryngology Head and Neck Department, Audiovestibular Unit, Alexandria University Hospitals, Alexandria, Egypt
| | - Mona Mourad
- Otolaryngology Head and Neck Department, Audiovestibular Unit, Alexandria University Hospitals, Alexandria, Egypt
| | - Nesrine Hamouda
- Otolaryngology Head and Neck Department, Phoniatrics Unit, Alexandria University Hospitals, Alexandria, Egypt
| | - Rania Abdou
- Otolaryngology Head and Neck Department, Phoniatrics Unit, Alexandria University Hospitals, Alexandria, Egypt
| | - Taima Salem
- Otolaryngology Head and Neck Department, Audiovestibular Unit, Alexandria University Hospitals, Alexandria, Egypt
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5
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Price KM, Wigg KG, Eising E, Feng Y, Blokland K, Wilkinson M, Kerr EN, Guger SL, Fisher SE, Lovett MW, Strug LJ, Barr CL. Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities. Transl Psychiatry 2022; 12:495. [PMID: 36446759 PMCID: PMC9709072 DOI: 10.1038/s41398-022-02250-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 11/30/2022] Open
Abstract
Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10-2, threshold = 2.5 × 10-2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10-2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10-4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations.
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Affiliation(s)
- Kaitlyn M Price
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Else Eising
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Yu Feng
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Departments of Statistical Sciences and Computer Science, Faculty of Arts and Science and Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
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6
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Lennon J, zur Lage P, von Kriegsheim A, Jarman AP. Strongly Truncated Dnaaf4 Plays a Conserved Role in Drosophila Ciliary Dynein Assembly as Part of an R2TP-Like Co-Chaperone Complex With Dnaaf6. Front Genet 2022; 13:943197. [PMID: 35873488 PMCID: PMC9298768 DOI: 10.3389/fgene.2022.943197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/16/2022] [Indexed: 11/15/2022] Open
Abstract
Axonemal dynein motors are large multi-subunit complexes that drive ciliary movement. Cytoplasmic assembly of these motor complexes involves several co-chaperones, some of which are related to the R2TP co-chaperone complex. Mutations of these genes in humans cause the motile ciliopathy, Primary Ciliary Dyskinesia (PCD), but their different roles are not completely known. Two such dynein (axonemal) assembly factors (DNAAFs) that are thought to function together in an R2TP-like complex are DNAAF4 (DYX1C1) and DNAAF6 (PIH1D3). Here we investigate the Drosophila homologues, CG14921/Dnaaf4 and CG5048/Dnaaf6. Surprisingly, Drosophila Dnaaf4 is truncated such that it completely lacks a TPR domain, which in human DNAAF4 is likely required to recruit HSP90. Despite this, we provide evidence that Drosophila Dnaaf4 and Dnaaf6 proteins can associate in an R2TP-like complex that has a conserved role in dynein assembly. Both are specifically expressed and required during the development of the two Drosophila cell types with motile cilia: mechanosensory chordotonal neurons and sperm. Flies that lack Dnaaf4 or Dnaaf6 genes are viable but with impaired chordotonal neuron function and lack motile sperm. We provide molecular evidence that Dnaaf4 and Dnaaf6 are required for assembly of outer dynein arms (ODAs) and a subset of inner dynein arms (IDAs).
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Affiliation(s)
- Jennifer Lennon
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
| | - Petra zur Lage
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
| | - Alex von Kriegsheim
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew P. Jarman
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
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7
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Animal models of developmental dyslexia: Where we are and what we are missing. Neurosci Biobehav Rev 2021; 131:1180-1197. [PMID: 34699847 DOI: 10.1016/j.neubiorev.2021.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/21/2022]
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental disorder and the most common learning disability among both school-aged children and across languages. Recently, sensory and cognitive mechanisms have been reported to be potential endophenotypes (EPs) for DD, and nine DD-candidate genes have been identified. Animal models have been used to investigate the etiopathological pathways that underlie the development of complex traits, as they enable the effects of genetic and/or environmental manipulations to be evaluated. Animal research designs have also been linked to cutting-edge clinical research questions by capitalizing on the use of EPs. For the present scoping review, we reviewed previous studies of murine models investigating the effects of DD-candidate genes. Moreover, we highlighted the use of animal models as an innovative way to unravel new insights behind the pathophysiology of reading (dis)ability and to assess cutting-edge preclinical models.
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8
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Unger N, Heim S, Hilger DI, Bludau S, Pieperhoff P, Cichon S, Amunts K, Mühleisen TW. Identification of Phonology-Related Genes and Functional Characterization of Broca's and Wernicke's Regions in Language and Learning Disorders. Front Neurosci 2021; 15:680762. [PMID: 34539327 PMCID: PMC8446646 DOI: 10.3389/fnins.2021.680762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 08/04/2021] [Indexed: 12/02/2022] Open
Abstract
Impaired phonological processing is a leading symptom of multifactorial language and learning disorders suggesting a common biological basis. Here we evaluated studies of dyslexia, dyscalculia, specific language impairment (SLI), and the logopenic variant of primary progressive aphasia (lvPPA) seeking for shared risk genes in Broca's and Wernicke's regions, being key for phonological processing within the complex language network. The identified "phonology-related genes" from literature were functionally characterized using Atlas-based expression mapping (JuGEx) and gene set enrichment. Out of 643 publications from the last decade until now, we extracted 21 candidate genes of which 13 overlapped with dyslexia and SLI, six with dyslexia and dyscalculia, and two with dyslexia, dyscalculia, and SLI. No overlap was observed between the childhood disorders and the late-onset lvPPA often showing symptoms of learning disorders earlier in life. Multiple genes were enriched in Gene Ontology terms of the topics learning (CNTNAP2, CYFIP1, DCDC2, DNAAF4, FOXP2) and neuronal development (CCDC136, CNTNAP2, CYFIP1, DCDC2, KIAA0319, RBFOX2, ROBO1). Twelve genes showed above-average expression across both regions indicating moderate-to-high gene activity in the investigated cortical part of the language network. Of these, three genes were differentially expressed suggesting potential regional specializations: ATP2C2 was upregulated in Broca's region, while DNAAF4 and FOXP2 were upregulated in Wernicke's region. ATP2C2 encodes a magnesium-dependent calcium transporter which fits with reports about disturbed calcium and magnesium levels for dyslexia and other communication disorders. DNAAF4 (formerly known as DYX1C1) is involved in neuronal migration supporting the hypothesis of disturbed migration in dyslexia. FOXP2 is a transcription factor that regulates a number of genes involved in development of speech and language. Overall, our interdisciplinary and multi-tiered approach provided evidence that genetic and transcriptional variation of ATP2C2, DNAAF4, and FOXP2 may play a role in physiological and pathological aspects of phonological processing.
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Affiliation(s)
- Nina Unger
- Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Stefan Heim
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany
- JARA-Brain, Jülich-Aachen Research Alliance, Jülich, Germany
| | - Dominique I. Hilger
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Sebastian Bludau
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Peter Pieperhoff
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Sven Cichon
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- Department of Biomedicine, University of Basel, Basel, Switzerland
- Institute of Medical Genetics and Pathology, University Hospital Basel, Basel, Switzerland
| | - Katrin Amunts
- Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- JARA-Brain, Jülich-Aachen Research Alliance, Jülich, Germany
| | - Thomas W. Mühleisen
- Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- Department of Biomedicine, University of Basel, Basel, Switzerland
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9
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The Polygenic Nature and Complex Genetic Architecture of Specific Learning Disorder. Brain Sci 2021; 11:brainsci11050631. [PMID: 34068951 PMCID: PMC8156942 DOI: 10.3390/brainsci11050631] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/16/2022] Open
Abstract
Specific Learning Disorder (SLD) is a multifactorial, neurodevelopmental disorder which may involve persistent difficulties in reading (dyslexia), written expression and/or mathematics. Dyslexia is characterized by difficulties with speed and accuracy of word reading, deficient decoding abilities, and poor spelling. Several studies from different, but complementary, scientific disciplines have investigated possible causal/risk factors for SLD. Biological, neurological, hereditary, cognitive, linguistic-phonological, developmental and environmental factors have been incriminated. Despite worldwide agreement that SLD is highly heritable, its exact biological basis remains elusive. We herein present: (a) an update of studies that have shaped our current knowledge on the disorder’s genetic architecture; (b) a discussion on whether this genetic architecture is ‘unique’ to SLD or, alternatively, whether there is an underlying common genetic background with other neurodevelopmental disorders; and, (c) a brief discussion on whether we are at a position of generating meaningful correlations between genetic findings and anatomical data from neuroimaging studies or specific molecular/cellular pathways. We conclude with open research questions that could drive future research directions.
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10
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Developmental dyslexia: A new look at clinical features and brain mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2020. [PMID: 32977895 DOI: 10.1016/b978-0-444-64148-9.00004-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Developmental dyslexia is the commonest "specific learning disorder" (DSM-5) or "developmental learning disorder with impairment in reading" (ICD-11). This impairment in reading acquisition is related to a defect in the installation of cognitive precursors necessary to master the grapheme-phoneme conversion. Its origin is largely genetic, but many environmental factors seem capable of modulating symptom intensity. Three types of presentation, roughly equal in occurrence, are useful to distinguish according to the associated disorders (language, attentional, and/or motor coordination), thus suggesting, at least in part, potentially different mechanisms at their origin. In adolescence and adulthood the clinical presentation tends to bear a more uniform pattern, covering a large range of severity depending on each person's ability to compensate for their deficit. Research has demonstrated dysfunction of specific brain areas during reading-related tasks (using fMRI), essentially in the left cerebral hemisphere, but also atypical patterns of connectivity (using diffusion imaging), further supplemented by functional connectivity studies at rest. The current therapeutic recommendations emphasize the need for multidisciplinary care, giving priority, depending on the clinical form, to the language, psychomotor, or neuropsychologic aspects of rehabilitation. Various training methods whose effectiveness has been scientifically tested are reviewed, emphasizing those exploiting the hypothesis of a lack of intermodal connectivity between separate cognitive systems.
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11
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Bieder A, Yoshihara M, Katayama S, Krjutškov K, Falk A, Kere J, Tapia-Páez I. Dyslexia Candidate Gene and Ciliary Gene Expression Dynamics During Human Neuronal Differentiation. Mol Neurobiol 2020; 57:2944-2958. [PMID: 32445086 PMCID: PMC7320047 DOI: 10.1007/s12035-020-01905-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/19/2020] [Indexed: 11/30/2022]
Abstract
Developmental dyslexia (DD) is a neurodevelopmental condition with complex genetic mechanisms. A number of candidate genes have been identified, some of which are linked to neuronal development and migration and to ciliary functions. However, expression and regulation of these genes in human brain development and neuronal differentiation remain uncharted. Here, we used human long-term self-renewing neuroepithelial stem (lt-NES, here termed NES) cells derived from human induced pluripotent stem cells to study neuronal differentiation in vitro. We characterized gene expression changes during differentiation by using RNA sequencing and validated dynamics for selected genes by qRT-PCR. Interestingly, we found that genes related to cilia were significantly enriched among upregulated genes during differentiation, including genes linked to ciliopathies with neurodevelopmental phenotypes. We confirmed the presence of primary cilia throughout neuronal differentiation. Focusing on dyslexia candidate genes, 33 out of 50 DD candidate genes were detected in NES cells by RNA sequencing, and seven candidate genes were upregulated during differentiation to neurons, including DYX1C1 (DNAAF4), a highly replicated DD candidate gene. Our results suggest a role of ciliary genes in differentiating neuronal cells and show that NES cells provide a relevant human neuronal model to study ciliary and DD candidate genes.
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Affiliation(s)
- Andrea Bieder
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 9, 141 57, Huddinge, Sweden.
| | - Masahito Yoshihara
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 9, 141 57, Huddinge, Sweden
| | - Shintaro Katayama
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 9, 141 57, Huddinge, Sweden
| | - Kaarel Krjutškov
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 9, 141 57, Huddinge, Sweden.,Competence Centre on Health Technologies, Tartu, Estonia.,Research Program of Molecular Neurology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Anna Falk
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 9, 141 57, Huddinge, Sweden. .,Research Program of Molecular Neurology, Research Programs Unit, University of Helsinki, Helsinki, Finland. .,Folkhälsan Institute of Genetics, Helsinki, Finland. .,School of Basic and Medical Biosciences, King's College London, London, UK.
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12
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Price KM, Wigg KG, Feng Y, Blokland K, Wilkinson M, He G, Kerr EN, Carter TC, Guger SL, Lovett MW, Strug LJ, Barr CL. Genome-wide association study of word reading: Overlap with risk genes for neurodevelopmental disorders. GENES BRAIN AND BEHAVIOR 2020; 19:e12648. [PMID: 32108986 DOI: 10.1111/gbb.12648] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 01/28/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022]
Abstract
Reading disabilities (RD) are the most common neurocognitive disorder, affecting 5% to 17% of children in North America. These children often have comorbid neurodevelopmental/psychiatric disorders, such as attention deficit/hyperactivity disorder (ADHD). The genetics of RD and their overlap with other disorders is incompletely understood. To contribute to this, we performed a genome-wide association study (GWAS) for word reading. Then, using summary statistics from neurodevelopmental/psychiatric disorders, we computed polygenic risk scores (PRS) and used them to predict reading ability in our samples. This enabled us to test the shared aetiology between RD and other disorders. The GWAS consisted of 5.3 million single nucleotide polymorphisms (SNPs) and two samples; a family-based sample recruited for reading difficulties in Toronto (n = 624) and a population-based sample recruited in Philadelphia [Philadelphia Neurodevelopmental Cohort (PNC)] (n = 4430). The Toronto sample SNP-based analysis identified suggestive SNPs (P ~ 5 × 10-7 ) in the ARHGAP23 gene, which is implicated in neuronal migration/axon pathfinding. The PNC gene-based analysis identified significant associations (P < 2.72 × 10-6 ) for LINC00935 and CCNT1, located in the region of the KANSL2/CCNT1/LINC00935/SNORA2B/SNORA34/MIR4701/ADCY6 genes on chromosome 12q, with near significant SNP-based analysis. PRS identified significant overlap between word reading and intelligence (R2 = 0.18, P = 7.25 × 10-181 ), word reading and educational attainment (R2 = 0.07, P = 4.91 × 10-48 ) and word reading and ADHD (R2 = 0.02, P = 8.70 × 10-6 ; threshold for significance = 7.14 × 10-3 ). Overlap was also found between RD and autism spectrum disorder (ASD) as top-ranked genes were previously implicated in autism by rare and copy number variant analyses. These findings support shared risk between word reading, cognitive measures, educational outcomes and neurodevelopmental disorders, including ASD.
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Affiliation(s)
- Kaitlyn M Price
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yu Feng
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gengming He
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Tasha-Cate Carter
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Holland Bloorview Rehabilitation Hospital, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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13
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Landi N, Perdue M. Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review. LANGUAGE AND LINGUISTICS COMPASS 2019; 13:e12349. [PMID: 31844423 PMCID: PMC6913889 DOI: 10.1111/lnc3.12349] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Developmental disorders of spoken and written language are heterogeneous in nature with impairments observed across various linguistic, cognitive, and sensorimotor domains. These disorders are also associated with characteristic patterns of atypical neural structure and function that are observable early in development, often before formal schooling begins. Established patterns of heritability point toward genetic contributions, and molecular genetics approaches have identified genes that play a role in these disorders. Still, identified genes account for only a limited portion of phenotypic variance in complex developmental disorders, described as the problem of "missing heritability." The characterization of intermediate phenotypes at the neural level may fill gaps in our understanding of heritability patterns in complex disorders, and the emerging field of neuroimaging genetics offers a promising approach to accomplish this goal. The neuroimaging genetics approach is gaining prevalence in language- and reading-related research as it is well-suited to incorporate behavior, genetics, and neurobiology into coherent etiological models of complex developmental disorders. Here, we review research applying the neuroimaging genetics approach to the study of specific reading disability (SRD) and developmental language disorder (DLD), much of which links genes with known neurodevelopmental function to functional and structural abnormalities in the brain.
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Affiliation(s)
- Nicole Landi
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States; Haskins Laboratories, United States
| | - Meaghan Perdue
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States; Haskins Laboratories, United States
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14
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Krafnick AJ, Evans TM. Neurobiological Sex Differences in Developmental Dyslexia. Front Psychol 2019; 9:2669. [PMID: 30687153 PMCID: PMC6336691 DOI: 10.3389/fpsyg.2018.02669] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 12/12/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding sex differences at the neurobiological level has become increasingly crucial in both basic and applied research. In the study of developmental dyslexia, early neuroimaging investigations were dominated by male-only or male-dominated samples, due at least in part to males being diagnosed more frequently. While recent studies more consistently balance the inclusion of both sexes, there has been little movement toward directly characterizing potential sex differences of the disorder. However, a string of recent work suggests that the brain basis of dyslexia may indeed be different in males and females. This potential sex difference has implications for existing models of dyslexia, and would inform approaches to the remediation of reading difficulties. This article reviews recent evidence for sex differences in dyslexia, discusses the impact these studies have on the understanding of the brain basis of dyslexia, and provides a framework for how these differential neuroanatomical profiles may develop.
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Affiliation(s)
- Anthony J Krafnick
- Psychology Department, Dominican University, River Forest, IL, United States
| | - Tanya M Evans
- Center for Advanced Study of Teaching and Learning, Curry School of Education and Human Development, University of Virginia, Charlottesville, VA, United States
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15
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Guidi LG, Velayos‐Baeza A, Martinez‐Garay I, Monaco AP, Paracchini S, Bishop DVM, Molnár Z. The neuronal migration hypothesis of dyslexia: A critical evaluation 30 years on. Eur J Neurosci 2018; 48:3212-3233. [PMID: 30218584 PMCID: PMC6282621 DOI: 10.1111/ejn.14149] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/06/2018] [Accepted: 08/13/2018] [Indexed: 12/29/2022]
Abstract
The capacity for language is one of the key features underlying the complexity of human cognition and its evolution. However, little is known about the neurobiological mechanisms that mediate normal or impaired linguistic ability. For developmental dyslexia, early postmortem studies conducted in the 1980s linked the disorder to subtle defects in the migration of neurons in the developing neocortex. These early studies were reinforced by human genetic analyses that identified dyslexia susceptibility genes and subsequent evidence of their involvement in neuronal migration. In this review, we examine recent experimental evidence that does not support the link between dyslexia and neuronal migration. We critically evaluate gene function studies conducted in rodent models and draw attention to the lack of robust evidence from histopathological and imaging studies in humans. Our review suggests that the neuronal migration hypothesis of dyslexia should be reconsidered, and the neurobiological basis of dyslexia should be approached with a fresh start.
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Affiliation(s)
- Luiz G. Guidi
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Isabel Martinez‐Garay
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Division of NeuroscienceSchool of BiosciencesCardiff UniversityCardiffUK
| | | | | | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
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16
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Devasenapathy S, Midha R, Naskar T, Mehta A, Prajapati B, Ummekulsum M, Sagar R, Singh NC, Sinha S. A pilot Indian family-based association study between dyslexia and Reelin pathway genes, DCDC2 and ROBO1, identifies modest association with a triallelic unit TAT in the gene RELN. Asian J Psychiatr 2018; 37:121-129. [PMID: 30199849 DOI: 10.1016/j.ajp.2018.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/20/2018] [Accepted: 08/19/2018] [Indexed: 10/28/2022]
Abstract
Dyslexia is a neurodevelopmental disorder that manifests as a reading disability despite normal intelligence and adequate educational opportunity. Twin and family studies have indicated a genetic component, while genome-wide studies have implicated a number of susceptibility genes, most of which have direct or indirect roles in neuronal migration. Reelin (RELN) has important biological functions facilitating migration of neurons. Polymorphisms in RELN have been implicated in related disorders like autism and schizophrenia but have not been examined in dyslexia. We hypothesized that not only RELN, but its interactors in the neuronal migration pathway may play roles in the etiology of dyslexia. Twenty two functional variants across six RELN signalling genes (RELN, VLDLR, APOER2, DAB1, LIS1 and NDEL1) and two dyslexia candidate genes (DCDC2 and ROBO1) were analyzed for association in twenty six nuclear and three extended families with individuals affected with dyslexia. Univariate association analysis was suggestive of association (puncorrected = 0.01) with rs362746 in RELN which however did not withstand Bonferroni corrections (pcorrected = 0.21). Multimarker tests indicated significant association (p = 0.037), based on which we tested for haplotype associations. Although there were no significant haplotypic associations, we found that a three marker unit with rs3808039 and rs2072403 flanking and independently in linkage disequilibrium with rs362746 was significantly overtransmitted (risk allelic combination - TAT) to dyslexia affected individuals in the sample (p = 0.002). Our results suggest preliminary evidence for a new potential risk variant in the RELN locus for dyslexia.
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Affiliation(s)
| | - Rashi Midha
- National Brain Research Centre, Manesar, Haryana, 122051, India
| | - Teesta Naskar
- National Brain Research Centre, Manesar, Haryana, 122051, India
| | - Anuradha Mehta
- National Brain Research Centre, Manesar, Haryana, 122051, India
| | | | | | - Rajesh Sagar
- Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, 110026, India
| | - Nandini C Singh
- National Brain Research Centre, Manesar, Haryana, 122051, India
| | - Subrata Sinha
- National Brain Research Centre, Manesar, Haryana, 122051, India
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17
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The Influence of Dyslexia Candidate Genes on Reading Skill in Old Age. Behav Genet 2018; 48:351-360. [PMID: 29959602 PMCID: PMC6097729 DOI: 10.1007/s10519-018-9913-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/23/2018] [Indexed: 11/27/2022]
Abstract
A number of candidate genes for reading and language impairment have been replicated, primarily in samples of children with developmental disability or delay, although these genes are also supported in adolescent population samples. The present study used a systematic approach to test 14 of these candidate genes for association with reading assessed in late adulthood (two cohorts with mean ages of 70 and 79 years). Gene-sets (14 candidates, axon-guidance and neuron migration pathways) and individual SNPs within each gene of interest were tested for association using imputed data referenced to the 1000 genomes European panel. Using the results from the genome-wide association (GWA) meta-analysis of the two cohorts (N = 1217), a competitive gene-set analysis showed that the candidate gene-set was associated with the reading index (p = .016) at a family wise error rate corrected significance level. Neither axon guidance nor neuron migration pathways were significant. Whereas individual SNP associations within CYP19A1, DYX1C1, CNTNAP2 and DIP2A genes (p < .05) did not reach corrected significance their allelic effects were in the same direction as past available reports. These results suggest that reading skill in normal adults shares the same genetic substrate as reading in adolescents, and clinically disordered reading, and highlights the utility of adult samples to increase sample sizes in the genetic study of developmental disorders.
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18
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Ji ZY, Sha YW, Ding L, Li P. Genetic factors contributing to human primary ciliary dyskinesia and male infertility. Asian J Androl 2018; 19:515-520. [PMID: 27270341 PMCID: PMC5566842 DOI: 10.4103/1008-682x.181227] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Primary ciliary dyskinesia (PCD) is an autosomal-recessive disorder resulting from the loss of normal ciliary function. Symptoms include neonatal respiratory distress, chronic sinusitis, bronchiectasis, situs inversus, and infertility. However, only 15 PCD-associated genes have been identified to cause male infertility to date. Owing to the genetic heterogeneity of PCD, comprehensive molecular genetic testing is not considered the standard of care. Here, we provide an update of the progress on the identification of genetic factors related to PCD associated with male infertility, summarizing the underlying molecular mechanisms, and discuss the clinical implications of these findings. Further research in this field will impact the diagnostic strategy for male infertility, enabling clinicians to provide patients with informed genetic counseling, and help to adopt the best course of treatment for developing directly targeted personalized medicine.
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Affiliation(s)
- Zhi-Yong Ji
- The Center for Reproductive Medicine, Xiamen Maternity and Child Care Hospital, No. 10 Zhenhai Road, Xiamen, China
| | - Yan-Wei Sha
- The Center for Reproductive Medicine, Xiamen Maternity and Child Care Hospital, No. 10 Zhenhai Road, Xiamen, China
| | - Lu Ding
- The Center for Reproductive Medicine, Xiamen Maternity and Child Care Hospital, No. 10 Zhenhai Road, Xiamen, China
| | - Ping Li
- The Center for Reproductive Medicine, Xiamen Maternity and Child Care Hospital, No. 10 Zhenhai Road, Xiamen, China
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19
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Langer N, Peysakhovich B, Zuk J, Drottar M, Sliva DD, Smith S, Becker BLC, Grant PE, Gaab N. White Matter Alterations in Infants at Risk for Developmental Dyslexia. Cereb Cortex 2018; 27:1027-1036. [PMID: 26643353 DOI: 10.1093/cercor/bhv281] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Developmental dyslexia (DD) is a heritable condition characterized by persistent difficulties in learning to read. White matter alterations in left-lateralized language areas, particularly in the arcuate fasciculus (AF), have been observed in DD, and diffusion properties within the AF correlate with (pre-)reading skills as early as kindergarten. However, it is unclear how early these alterations can be observed. We investigated white matter structure in 14 infants with (FHD+; ages 6.6-17.6 months) and 18 without (FHD-; ages 5.1-17.6 months) familial risk for DD. Diffusion scans were acquired during natural sleep, and early language skills were assessed. Tractography for bilateral AF was reconstructed using manual and automated methods, allowing for independent validation of results. Fractional anisotropy (FA) was calculated at multiple nodes along the tracts for more precise localization of group differences. The analyses revealed significantly lower FA in the left AF for FHD+ compared with FHD- infants, particularly in the central portion of the tract. Moreover, expressive language positively correlated with FA across groups. Our results demonstrate that atypical brain development associated with DD is already present within the first 18 months of life, suggesting that the deficits associated with DD may result from altered structural connectivity in left-hemispheric regions.
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Affiliation(s)
- Nicolas Langer
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA.,Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Peysakhovich
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA
| | - Jennifer Zuk
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA.,Harvard Medical School, Boston, MA 02115, USA
| | - Marie Drottar
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Danielle D Sliva
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA.,Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Sara Smith
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA
| | - Bryce L C Becker
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA
| | - P Ellen Grant
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA 02115, USA.,Harvard Medical School, Boston, MA 02115, USA
| | - Nadine Gaab
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, Boston, MA, USA.,Harvard Medical School, Boston, MA 02115, USA.,Harvard Graduate School of Education, Cambridge, MA 02138, USA
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20
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Sharma P, Sagar R. Unfolding the genetic pathways of dyslexia in Asian population: A review. Asian J Psychiatr 2017; 30:225-229. [PMID: 28619243 DOI: 10.1016/j.ajp.2017.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 05/31/2017] [Accepted: 06/06/2017] [Indexed: 01/06/2023]
Abstract
Dyslexia also known as specific reading disorder is a complex heritable disorder with unexpected difficulty in learning to read and spell despite adequate intelligence, education, environment, and normal senses. Over past decades, researchers have attempted to characterize dyslexia neurobiological and genetic levels and unfold its pathophysiology. The genetic research on dyslexia has received attention in Asia from the last decade. Though limited by different constraints the studies from Asia have been able to gather significant evidence in this field. We present a review of studies of genetics in Asian population and suggest future directions.
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Affiliation(s)
- Pawan Sharma
- Department of Psychiatry, Patan Academy of Health Sciences, Kathmandu, Nepal.
| | - Rajesh Sagar
- Department of Psychiatry, All India Institute of Medical Sciences (AIIMS), New Delhi, India
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21
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Guidi LG, Mattley J, Martinez-Garay I, Monaco AP, Linden JF, Velayos-Baeza A, Molnár Z. Knockout Mice for Dyslexia Susceptibility Gene Homologs KIAA0319 and KIAA0319L have Unaffected Neuronal Migration but Display Abnormal Auditory Processing. Cereb Cortex 2017; 27:5831-5845. [PMID: 29045729 PMCID: PMC5939205 DOI: 10.1093/cercor/bhx269] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Developmental dyslexia is a neurodevelopmental disorder that affects reading ability caused by genetic and non-genetic factors. Amongst the susceptibility genes identified to date, KIAA0319 is a prime candidate. RNA-interference experiments in rats suggested its involvement in cortical migration but we could not confirm these findings in Kiaa0319-mutant mice. Given its homologous gene Kiaa0319L (AU040320) has also been proposed to play a role in neuronal migration, we interrogated whether absence of AU040320 alone or together with KIAA0319 affects migration in the developing brain. Analyses of AU040320 and double Kiaa0319;AU040320 knockouts (dKO) revealed no evidence for impaired cortical lamination, neuronal migration, neurogenesis or other anatomical abnormalities. However, dKO mice displayed an auditory deficit in a behavioral gap-in-noise detection task. In addition, recordings of click-evoked auditory brainstem responses revealed suprathreshold deficits in wave III amplitude in AU040320-KO mice, and more general deficits in dKOs. These findings suggest that absence of AU040320 disrupts firing and/or synchrony of activity in the auditory brainstem, while loss of both proteins might affect both peripheral and central auditory function. Overall, these results stand against the proposed role of KIAA0319 and AU040320 in neuronal migration and outline their relationship with deficits in the auditory system.
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Affiliation(s)
- Luiz G Guidi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Jane Mattley
- Ear Institute, University College London, London WC1X 8EE, UK
| | - Isabel Martinez-Garay
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Anthony P Monaco
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
- Current address: Office of the President, Ballou Hall, Tufts University, Medford, MA 02155, USA
| | - Jennifer F Linden
- Ear Institute, University College London, London WC1X 8EE, UK
- Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E 6BT, UK
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
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22
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Müller B, Schaadt G, Boltze J, Emmrich F, Skeide MA, Neef NE, Kraft I, Brauer J, Friederici AD, Kirsten H, Wilcke A. ATP2C2 and DYX1C1 are putative modulators of dyslexia-related MMR. Brain Behav 2017; 7:e00851. [PMID: 29201552 PMCID: PMC5698869 DOI: 10.1002/brb3.851] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/23/2017] [Accepted: 09/01/2017] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Dyslexia is a specific learning disorder affecting reading and spelling abilities. Its prevalence is ~5% in German-speaking individuals. Although the etiology of dyslexia largely remains to be determined, comprehensive evidence supports deficient phonological processing as a major contributing factor. An important prerequisite for phonological processing is auditory discrimination and, thus, essential for acquiring reading and spelling skills. The event-related potential Mismatch Response (MMR) is an indicator for auditory discrimination capabilities with dyslexics showing an altered late component of MMR in response to auditory input. METHODS In this study, we comprehensively analyzed associations of dyslexia-specific late MMRs with genetic variants previously reported to be associated with dyslexia-related phenotypes in multiple studies comprising 25 independent single-nucleotide polymorphisms (SNPs) within 10 genes. RESULTS First, we demonstrated validity of these SNPs for dyslexia in our sample by showing that additional inclusion of a polygenic risk score improved prediction of impaired writing compared with a model that used MMR alone. Secondly, a multifactorial regression analysis was conducted to uncover the subset of the 25 SNPs that is associated with the dyslexia-specific late component of MMR. In total, four independent SNPs within DYX1C1 and ATP2C2 were found to be associated with MMR stronger than expected from multiple testing. To explore potential pathomechanisms, we annotated these variants with functional data including tissue-specific expression analysis and eQTLs. CONCLUSION Our findings corroborate the late component of MMR as a potential endophenotype for dyslexia and support tripartite relationships between dyslexia-related SNPs, the late component of MMR and dyslexia.
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Affiliation(s)
- Bent Müller
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig Germany
| | - Gesa Schaadt
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany.,Department of Psychology Humboldt-Universität zu Berlin Berlin Germany
| | - Johannes Boltze
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig Germany.,Department of Medical Cell Technology Fraunhofer Research Institution for Marine Biotechnology Lübeck Germany.,Institute for Medical and Marine Biotechnology University of Lübeck Lübeck Germany
| | - Frank Emmrich
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig Germany
| | | | - Michael A Skeide
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Nicole E Neef
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Indra Kraft
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Jens Brauer
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Angela D Friederici
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Holger Kirsten
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig Germany.,Institute for Medical Informatics Statistics and Epidemiology University of Leipzig Leipzig Germany.,LIFE-Leipzig Research Center for Civilization Diseases University of Leipzig Leipzig Germany
| | - Arndt Wilcke
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig Germany
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23
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Rendall AR, Tarkar A, Contreras-Mora HM, LoTurco JJ, Fitch RH. Deficits in learning and memory in mice with a mutation of the candidate dyslexia susceptibility gene Dyx1c1. BRAIN AND LANGUAGE 2017; 172:30-38. [PMID: 25989970 PMCID: PMC4646737 DOI: 10.1016/j.bandl.2015.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/15/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Dyslexia is a learning disability characterized by difficulty learning to read and write. The underlying biological and genetic etiology remains poorly understood. One candidate gene, dyslexia susceptibility 1 candidate 1 (DYX1C1), has been shown to be associated with deficits in short-term memory in dyslexic populations. The purpose of the current study was to examine the behavioral phenotype of a mouse model with a homozygous conditional (forebrain) knockout of the rodent homolog Dyx1c1. Twelve Dyx1c1 conditional homozygous knockouts, 7 Dyx1c1 conditional heterozygous knockouts and 6 wild-type controls were behaviorally assessed. Mice with the homozygous Dyx1c1 knockout showed deficits on memory and learning, but not on auditory or motor tasks. These findings affirm existing evidence that DYX1C1 may play an underlying role in the development of neural systems important to learning and memory, and disruption of this function could contribute to the learning deficits seen in individuals with dyslexia.
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Affiliation(s)
- Amanda R Rendall
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States.
| | - Aarti Tarkar
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, Unit 3156, Storrs, CT 06269, United States
| | - Hector M Contreras-Mora
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States
| | - Joseph J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, Unit 3156, Storrs, CT 06269, United States
| | - R Holly Fitch
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States
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Martinez-Garay I, Guidi LG, Holloway ZG, Bailey MAG, Lyngholm D, Schneider T, Donnison T, Butt SJB, Monaco AP, Molnár Z, Velayos-Baeza A. Normal radial migration and lamination are maintained in dyslexia-susceptibility candidate gene homolog Kiaa0319 knockout mice. Brain Struct Funct 2017; 222:1367-1384. [PMID: 27510895 PMCID: PMC5368214 DOI: 10.1007/s00429-016-1282-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/26/2016] [Indexed: 12/18/2022]
Abstract
Developmental dyslexia is a common disorder with a strong genetic component, but the underlying molecular mechanisms are still unknown. Several candidate dyslexia-susceptibility genes, including KIAA0319, DYX1C1, and DCDC2, have been identified in humans. RNA interference experiments targeting these genes in rat embryos have shown impairments in neuronal migration, suggesting that defects in radial cortical migration could be involved in the disease mechanism of dyslexia. Here we present the first characterisation of a Kiaa0319 knockout mouse line. Animals lacking KIAA0319 protein do not show anatomical abnormalities in any of the layered structures of the brain. Neurogenesis and radial migration of cortical projection neurons are not altered, and the intrinsic electrophysiological properties of Kiaa0319-deficient neurons do not differ from those of wild-type neurons. Kiaa0319 overexpression in cortex delays radial migration, but does not affect final neuronal position. However, knockout animals show subtle differences suggesting possible alterations in anxiety-related behaviour and in sensorimotor gating. Our results do not reveal a migration disorder in the mouse model, adding to the body of evidence available for Dcdc2 and Dyx1c1 that, unlike in the rat in utero knockdown models, the dyslexia-susceptibility candidate mouse homolog genes do not play an evident role in neuronal migration. However, KIAA0319 protein expression seems to be restricted to the brain, not only in early developmental stages but also in adult mice, indicative of a role of this protein in brain function. The constitutive and conditional knockout lines reported here will be useful tools for further functional analyses of Kiaa0319.
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Affiliation(s)
- Isabel Martinez-Garay
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Division of Neuroscience, School of Biosciences, Cardiff University, Cardiff, UK
| | - Luiz G Guidi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Zoe G Holloway
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Melissa A G Bailey
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Daniel Lyngholm
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Tomasz Schneider
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Timothy Donnison
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Simon J B Butt
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Anthony P Monaco
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Office of the President, Ballou Hall, Tufts University, Medford, MA, 02155, USA.
| | - Zoltán Molnár
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK.
| | - Antonio Velayos-Baeza
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
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25
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Xia Z, Hancock R, Hoeft F. Neurobiological bases of reading disorder Part I: Etiological investigations. LANGUAGE AND LINGUISTICS COMPASS 2017; 11:e12239. [PMID: 28785303 PMCID: PMC5543813 DOI: 10.1111/lnc3.12239] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 03/22/2017] [Indexed: 05/29/2023]
Abstract
While many studies have focused on identifying the neural and behavioral characteristics of decoding-based reading disorder (RD, aka developmental dyslexia), the etiology of RD remains largely unknown and understudied. Because the brain plays an intermediate role between genetic factors and behavioral outcomes, it is promising to address causality from a neural perspective. In the current, Part I of the two-part review, we discuss neuroimaging approaches to addressing the causality issue and review the results of studies that have employed these approaches. We assume that if a neural signature were associated with RD etiology, it would (a) manifest across comparisons in different languages, (b) be experience independent and appear in comparisons between RD and reading-matched controls, (c) be present both pre- and post-intervention, (d) be found in at-risk, pre-reading children and (e) be associated with genetic risk. We discuss each of these five characteristics in turn and summarize the studies that have examined each of them. The available literature provides evidence that anomalies in left temporo-parietal cortex, and possibly occipito-temporal cortex, may be closely related to the etiology of RD. Improved understanding of the etiology of RD can help improve the accuracy of early detection and enable targeted intervention of cognitive processes that are amenable to change, leading to improved outcomes in at-risk or affected populations.
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Affiliation(s)
- Zhichao Xia
- Department of Psychiatry and Weill Institute for Neurosciences, University of California San Francisco, USA
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, China
| | - Roeland Hancock
- Department of Psychiatry and Weill Institute for Neurosciences, University of California San Francisco, USA
| | - Fumiko Hoeft
- Department of Psychiatry and Weill Institute for Neurosciences, University of California San Francisco, USA
- Haskins Laboratories, USA
- Department of Neuropsychiatry, Keio University School of Medicine, Japan
- Dyslexia Center, University of California San Francisco, USA
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26
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Genes, Gender, Environment, and Novel Functions of Estrogen Receptor Beta in the Susceptibility to Neurodevelopmental Disorders. Brain Sci 2017; 7:brainsci7030024. [PMID: 28241485 PMCID: PMC5366823 DOI: 10.3390/brainsci7030024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 12/30/2022] Open
Abstract
Many neurological disorders affect men and women differently regarding prevalence, progression, and severity. It is clear that many of these disorders may originate from defective signaling during fetal or perinatal brain development, which may affect males and females differently. Such sex-specific differences may originate from chromosomal or sex-hormone specific effects. This short review will focus on the estrogen receptor beta (ERβ) signaling during perinatal brain development and put it in the context of sex-specific differences in neurodevelopmental disorders. We will discuss ERβ’s recent discovery in directing DNA de-methylation to specific sites, of which one such site may bear consequences for the susceptibility to the neurological reading disorder dyslexia. We will also discuss how dysregulations in sex-hormone signaling, like those evoked by endocrine disruptive chemicals, may affect this and other neurodevelopmental disorders in a sex-specific manner through ERβ.
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Role of Splice Variants of Gtf2i, a Transcription Factor Localizing at Postsynaptic Sites, and Its Relation to Neuropsychiatric Diseases. Int J Mol Sci 2017; 18:ijms18020411. [PMID: 28212274 PMCID: PMC5343945 DOI: 10.3390/ijms18020411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/01/2017] [Accepted: 02/09/2017] [Indexed: 12/17/2022] Open
Abstract
We previously reported that various mRNAs were associated with postsynaptic density (PSD) purified from rat forebrain. Among the thousands of PSD-associated mRNAs, we highlight the biology of the general transcription factor II-I (Gtf2i) mRNA, focusing on the significance of its versatile splicing for targeting its own mRNA into dendrites, regulation of translation, and the effects of Gtf2i expression level as well as its relationship with neuropsychiatric disorders.
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28
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Trulioff A, Ermakov A, Malashichev Y. Primary Cilia as a Possible Link between Left-Right Asymmetry and Neurodevelopmental Diseases. Genes (Basel) 2017; 8:genes8020048. [PMID: 28125008 PMCID: PMC5333037 DOI: 10.3390/genes8020048] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/21/2016] [Accepted: 01/19/2017] [Indexed: 12/11/2022] Open
Abstract
Cilia have multiple functions in the development of the entire organism, and participate in the development and functioning of the central nervous system. In the last decade, studies have shown that they are implicated in the development of the visceral left-right asymmetry in different vertebrates. At the same time, some neuropsychiatric disorders, such as schizophrenia, autism, bipolar disorder, and dyslexia, are known to be associated with lateralization failure. In this review, we consider possible links in the mechanisms of determination of visceral asymmetry and brain lateralization, through cilia. We review the functions of seven genes associated with both cilia, and with neurodevelopmental diseases, keeping in mind their possible role in the establishment of the left-right brain asymmetry.
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Affiliation(s)
- Andrey Trulioff
- Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg 199034, Russia.
| | - Alexander Ermakov
- Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg 199034, Russia.
- Laboratory of Molecular Neurobiology, Department of Ecological Physiology, Institute of Experimental Medicine, ul. Akad. Pavlov, 12, Saint Petersburg 197376, Russia.
| | - Yegor Malashichev
- Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg 199034, Russia.
- Laboratory of Molecular Neurobiology, Department of Ecological Physiology, Institute of Experimental Medicine, ul. Akad. Pavlov, 12, Saint Petersburg 197376, Russia.
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Neurogenetics of developmental dyslexia: from genes to behavior through brain neuroimaging and cognitive and sensorial mechanisms. Transl Psychiatry 2017; 7:e987. [PMID: 28045463 PMCID: PMC5545717 DOI: 10.1038/tp.2016.240] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/15/2016] [Indexed: 01/18/2023] Open
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental deficit characterized by impaired reading acquisition, in spite of adequate neurological and sensorial conditions, educational opportunities and normal intelligence. Despite the successful characterization of DD-susceptibility genes, we are far from understanding the molecular etiological pathways underlying the development of reading (dis)ability. By focusing mainly on clinical phenotypes, the molecular genetics approach has yielded mixed results. More optimally reduced measures of functioning, that is, intermediate phenotypes (IPs), represent a target for researching disease-associated genetic variants and for elucidating the underlying mechanisms. Imaging data provide a viable IP for complex neurobehavioral disorders and have been extensively used to investigate both morphological, structural and functional brain abnormalities in DD. Performing joint genetic and neuroimaging studies in humans is an emerging strategy to link DD-candidate genes to the brain structure and function. A limited number of studies has already pursued the imaging-genetics integration in DD. However, the results are still not sufficient to unravel the complexity of the reading circuit due to heterogeneous study design and data processing. Here, we propose an interdisciplinary, multilevel, imaging-genetic approach to disentangle the pathways from genes to behavior. As the presence of putative functional genetic variants has been provided and as genetic associations with specific cognitive/sensorial mechanisms have been reported, new hypothesis-driven imaging-genetic studies must gain momentum. This approach would lead to the optimization of diagnostic criteria and to the early identification of 'biologically at-risk' children, supporting the definition of adequate and well-timed prevention strategies and the implementation of novel, specific remediation approach.
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SFPQ associates to LSD1 and regulates the migration of newborn pyramidal neurons in the developing cerebral cortex. Int J Dev Neurosci 2016; 57:1-11. [PMID: 28034769 DOI: 10.1016/j.ijdevneu.2016.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/16/2016] [Accepted: 12/20/2016] [Indexed: 12/24/2022] Open
Abstract
The development of the cerebral cortex requires the coordination of multiple processes ranging from the proliferation of progenitors to the migration and establishment of connectivity of the newborn neurons. Epigenetic regulation carried out by the COREST/LSD1 complex has been identified as a mechanism that regulates the development of pyramidal neurons of the cerebral cortex. We now identify the association of the multifunctional RNA-binding protein SFPQ to LSD1 during the development of the cerebral cortex. In vivo reduction of SFPQ dosage by in utero electroporation of a shRNA results in impaired radial migration of newborn pyramidal neurons, in a similar way to that observed when COREST or LSD1 expressions are decreased. Diminished SFPQ expression also associates to decreased proliferation of progenitor cells, while it does not affect the acquisition of neuronal fate. These results are compatible with the idea that SFPQ, plays an important role regulating proliferation and migration during the development of the cerebral cortex.
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Tammimies K, Bieder A, Lauter G, Sugiaman-Trapman D, Torchet R, Hokkanen ME, Burghoorn J, Castrén E, Kere J, Tapia-Páez I, Swoboda P. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor X (RFX) transcription factors through X-box promoter motifs. FASEB J 2016; 30:3578-3587. [PMID: 27451412 PMCID: PMC5024701 DOI: 10.1096/fj.201500124rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 07/05/2016] [Indexed: 11/11/2022]
Abstract
DYX1C1, DCDC2, and KIAA0319 are
three of the most replicated dyslexia candidate genes (DCGs). Recently, these DCGs
were implicated in functions at the cilium. Here, we investigate the regulation of
these DCGs by Regulatory Factor X transcription factors (RFX TFs), a gene family
known for transcriptionally regulating ciliary genes. We identify conserved X-box
motifs in the promoter regions of DYX1C1, DCDC2, and
KIAA0319 and demonstrate their functionality, as well as the
ability to recruit RFX TFs using reporter gene and electrophoretic mobility shift
assays. Furthermore, we uncover a complex regulation pattern between
RFX1, RFX2, and RFX3 and their
significant effect on modifying the endogenous expression of DYX1C1
and DCDC2 in a human retinal pigmented epithelial cell line
immortalized with hTERT (hTERT-RPE1). In addition, induction of ciliogenesis
increases the expression of RFX TFs and DCGs. At the protein level, we show that
endogenous DYX1C1 localizes to the base of the cilium, whereas DCDC2 localizes along
the entire axoneme of the cilium, thereby validating earlier localization studies
using overexpression models. Our results corroborate the emerging role of DCGs in
ciliary function and characterize functional noncoding elements, X-box promoter
motifs, in DCG promoter regions, which thus can be targeted for mutation screening in
dyslexia and ciliopathies associated with these genes.—Tammimies, K., Bieder,
A., Lauter, G., Sugiaman-Trapman, D., Torchet, R., Hokkanen, M.-E., Burghoorn, J.,
Castrén, E., Kere, J., Tapia-Páez, I., Swoboda, P. Ciliary dyslexia
candidate genes DYX1C1 and DCDC2 are regulated by
Regulatory Factor (RF) X transcription factors through X-box promoter motifs.
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Affiliation(s)
- Kristiina Tammimies
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; Center of Neurodevelopmental Disorders (KIND), Pediatric Neuropsychiatry Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Andrea Bieder
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Gilbert Lauter
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | - Rachel Torchet
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | - Jan Burghoorn
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Eero Castrén
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland; and Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Isabel Tapia-Páez
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden;
| | - Peter Swoboda
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden;
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Serrallach B, Groß C, Bernhofs V, Engelmann D, Benner J, Gündert N, Blatow M, Wengenroth M, Seitz A, Brunner M, Seither S, Parncutt R, Schneider P, Seither-Preisler A. Neural Biomarkers for Dyslexia, ADHD, and ADD in the Auditory Cortex of Children. Front Neurosci 2016; 10:324. [PMID: 27471442 PMCID: PMC4945653 DOI: 10.3389/fnins.2016.00324] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/27/2016] [Indexed: 11/13/2022] Open
Abstract
Dyslexia, attention deficit hyperactivity disorder (ADHD), and attention deficit disorder (ADD) show distinct clinical profiles that may include auditory and language-related impairments. Currently, an objective brain-based diagnosis of these developmental disorders is still unavailable. We investigated the neuro-auditory systems of dyslexic, ADHD, ADD, and age-matched control children (N = 147) using neuroimaging, magnetencephalography and psychoacoustics. All disorder subgroups exhibited an oversized left planum temporale and an abnormal interhemispheric asynchrony (10–40 ms) of the primary auditory evoked P1-response. Considering right auditory cortex morphology, bilateral P1 source waveform shapes, and auditory performance, the three disorder subgroups could be reliably differentiated with outstanding accuracies of 89–98%. We therefore for the first time provide differential biomarkers for a brain-based diagnosis of dyslexia, ADHD, and ADD. The method allowed not only allowed for clear discrimination between two subtypes of attentional disorders (ADHD and ADD), a topic controversially discussed for decades in the scientific community, but also revealed the potential for objectively identifying comorbid cases. Noteworthy, in children playing a musical instrument, after three and a half years of training the observed interhemispheric asynchronies were reduced by about 2/3, thus suggesting a strong beneficial influence of music experience on brain development. These findings might have far-reaching implications for both research and practice and enable a profound understanding of the brain-related etiology, diagnosis, and musically based therapy of common auditory-related developmental disorders and learning disabilities.
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Affiliation(s)
- Bettina Serrallach
- Department of Neurology, Section of Biomagnetism, University Hospital HeidelbergHeidelberg, Germany; Division of Neuroradiology, University Hospital HeidelbergHeidelberg, Germany; Division of Radiology and Nuclear Medicine, Kantonsspital St. GallenSt. Gallen, Switzerland
| | - Christine Groß
- Department of Neurology, Section of Biomagnetism, University Hospital Heidelberg Heidelberg, Germany
| | | | - Dorte Engelmann
- Department of Neurology, Section of Biomagnetism, University Hospital Heidelberg Heidelberg, Germany
| | - Jan Benner
- Department of Neurology, Section of Biomagnetism, University Hospital HeidelbergHeidelberg, Germany; Division of Neuroradiology, Department of Radiology, University of Basel HospitalBasel, Switzerland
| | - Nadine Gündert
- Department of Neurology, Section of Biomagnetism, University Hospital Heidelberg Heidelberg, Germany
| | - Maria Blatow
- Division of Neuroradiology, Department of Radiology, University of Basel Hospital Basel, Switzerland
| | - Martina Wengenroth
- Department of Neuroradiology, University Hospital Lübeck Lübeck, Germany
| | - Angelika Seitz
- Department of Pediatric Neurology, University Hospital Heidelberg Heidelberg, Germany
| | - Monika Brunner
- Phoniatrics and Pedaudiology, University Hospital Heidelberg Heidelberg, Germany
| | - Stefan Seither
- Institute of Psychology, University of GrazGraz, Austria; BioTechMed GrazGraz, Austria
| | - Richard Parncutt
- Centre for Systematic Musicology, University of Graz Graz, Austria
| | - Peter Schneider
- Department of Neurology, Section of Biomagnetism, University Hospital HeidelbergHeidelberg, Germany; Division of Neuroradiology, University Hospital HeidelbergHeidelberg, Germany
| | - Annemarie Seither-Preisler
- Department of Neurology, Section of Biomagnetism, University Hospital HeidelbergHeidelberg, Germany; Division of Neuroradiology, University Hospital HeidelbergHeidelberg, Germany; Institute of Psychology, University of GrazGraz, Austria; BioTechMed GrazGraz, Austria; Centre for Systematic Musicology, University of GrazGraz, Austria
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Ozernov-Palchik O, Yu X, Wang Y, Gaab N. Lessons to be learned: how a comprehensive neurobiological framework of atypical reading development can inform educational practice. Curr Opin Behav Sci 2016; 10:45-58. [PMID: 27766284 DOI: 10.1016/j.cobeha.2016.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Dyslexia is a heritable reading disorder with an estimated prevalence of 5-17%. A multiple deficit model has been proposed that illustrates dyslexia as an outcome of multiple risks and protective factors interacting at the genetic, neural, cognitive, and environmental levels. Here we review the evidence on each of these levels and discuss possible underlying mechanisms and their reciprocal interactions along a developmental timeline. Current and potential implications of neuroscientific findings for contemporary challenges in the field of dyslexia, as well as for reading development and education in general, are then discussed.
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Affiliation(s)
- Ola Ozernov-Palchik
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Center for Reading and Language Research, Tufts University, Medford, MA 02155, United States
| | - Xi Yu
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States
| | - Yingying Wang
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States
| | - Nadine Gaab
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States; Harvard Graduate School of Education, Cambridge, MA 02138, United States
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34
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Paracchini S, Diaz R, Stein J. Advances in Dyslexia Genetics—New Insights Into the Role of Brain Asymmetries. ADVANCES IN GENETICS 2016; 96:53-97. [DOI: 10.1016/bs.adgen.2016.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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35
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Metzger J, Karwath M, Tonda R, Beltran S, Águeda L, Gut M, Gut IG, Distl O. Runs of homozygosity reveal signatures of positive selection for reproduction traits in breed and non-breed horses. BMC Genomics 2015; 16:764. [PMID: 26452642 PMCID: PMC4600213 DOI: 10.1186/s12864-015-1977-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 10/03/2015] [Indexed: 11/24/2022] Open
Abstract
Background Modern horses represent heterogeneous populations specifically selected for appearance and performance. Genomic regions under high selective pressure show characteristic runs of homozygosity (ROH) which represent a low genetic diversity. This study aims at detecting the number and functional distribution of ROHs in different horse populations using next generation sequencing data. Methods Next generation sequencing was performed for two Sorraia, one Dülmen Horse, one Arabian, one Saxon-Thuringian Heavy Warmblood, one Thoroughbred and four Hanoverian. After quality control reads were mapped to the reference genome EquCab2.70. ROH detection was performed using PLINK, version 1.07 for a trimmed dataset with 11,325,777 SNPs and a mean read depth of 12. Stretches with homozygous genotypes of >40 kb as well as >400 kb were defined as ROHs. SNPs within consensus ROHs were tested for neutrality. Functional classification was done for genes annotated within ROHs using PANTHER gene list analysis and functional variants were tested for their distribution among breed or non-breed groups. Results ROH detection was performed using whole genome sequences of ten horses of six populations representing various breed types and non-breed horses. In total, an average number of 3492 ROHs were detected in windows of a minimum of 50 consecutive homozygous SNPs and an average number of 292 ROHs in windows of 500 consecutive homozygous SNPs. Functional analyses of private ROHs in each horse revealed a high frequency of genes affecting cellular, metabolic, developmental, immune system and reproduction processes. In non-breed horses, 198 ROHs in 50-SNP windows and seven ROHs in 500-SNP windows showed an enrichment of genes involved in reproduction, embryonic development, energy metabolism, muscle and cardiac development whereas all seven breed horses revealed only three common ROHs in 50-SNP windows harboring the fertility-related gene YES1. In the Hanoverian, a total of 18 private ROHs could be shown to be located in the region of genes potentially involved in neurologic control, signaling, glycogen balance and reproduction. Comparative analysis of homozygous stretches common in all ten horses displayed three ROHs which were all located in the region of KITLG, the ligand of KIT known to be involved in melanogenesis, haematopoiesis and gametogenesis. Conclusions The results of this study give a comprehensive insight into the frequency and number of ROHs in various horses and their potential influence on population diversity and selection pressures. Comparisons of breed and non-breed horses suggest a significant artificial as well as natural selection pressure on reproduction performance in all types of horse populations. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1977-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Julia Metzger
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Bünteweg 17p, 30559, Hannover, Germany.
| | - Matthias Karwath
- Lower Saxony State Office for the Environment, Agriculture and Geology, Unit 74, Animal Breeding and Hygiene, Schlossallee 1, 01468, Moritzburg, Germany.
| | - Raul Tonda
- Centro Nacional de Análisis Genómico, Parc Científic de Barcelona, Torre I Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Sergi Beltran
- Centro Nacional de Análisis Genómico, Parc Científic de Barcelona, Torre I Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Lídia Águeda
- Centro Nacional de Análisis Genómico, Parc Científic de Barcelona, Torre I Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Marta Gut
- Centro Nacional de Análisis Genómico, Parc Científic de Barcelona, Torre I Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Ivo Glynne Gut
- Centro Nacional de Análisis Genómico, Parc Científic de Barcelona, Torre I Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Ottmar Distl
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Bünteweg 17p, 30559, Hannover, Germany.
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Kawauchi T. Cellullar insights into cerebral cortical development: focusing on the locomotion mode of neuronal migration. Front Cell Neurosci 2015; 9:394. [PMID: 26500496 PMCID: PMC4595654 DOI: 10.3389/fncel.2015.00394] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/22/2015] [Indexed: 02/01/2023] Open
Abstract
The mammalian brain consists of numerous compartments that are closely connected with each other via neural networks, comprising the basis of higher order brain functions. The highly specialized structure originates from simple pseudostratified neuroepithelium-derived neural progenitors located near the ventricle. A long journey by neurons from the ventricular side is essential for the formation of a sophisticated brain structure, including a mammalian-specific six-layered cerebral cortex. Neuronal migration consists of several contiguous steps, but the locomotion mode comprises a large part of the migration. The locomoting neurons exhibit unique features; a radial glial fiber-dependent migration requiring the endocytic recycling of N-cadherin and a neuron-specific migration mode with dilation/swelling formation that requires the actin and microtubule organization possibly regulated by cyclin-dependent kinase 5 (Cdk5), Dcx, p27(kip1), Rac1, and POSH. Here I will introduce the roles of various cellular events, such as cytoskeletal organization, cell adhesion, and membrane trafficking, in the regulation of the neuronal migration, with particular focus on the locomotion mode.
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Affiliation(s)
- Takeshi Kawauchi
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency Saitama, Japan ; Laboratory of Molecular Life Science, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation Kobe, Japan
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Jahan E, Rafiq AM, Otani H. In utero and exo utero fetal surgery on histogenesis of organs in animals. World J Surg Proced 2015; 5:198-207. [DOI: 10.5412/wjsp.v5.i2.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 01/22/2015] [Accepted: 03/18/2015] [Indexed: 02/06/2023] Open
Abstract
Until recently, fetal surgery was only used for fetuses with very poor prognosis who were likely to die without intervention. With advances in imaging, endoscopic techniques, anesthesia and novel interventions, fetal surgery is becoming a realistic option for conditions with less severe prognoses, where the aim is now to improve quality of life rather than simply allow survival. Until forty years ago, the uterus shielded the fetus from observation and therapy. Rapid changes in the diagnosis and treatment of human fetal anatomical abnormalities are due to improved fetal imaging studies, fetal sampling techniques (e.g., amniocentesis and chorionic villus sampling), and a better understanding of fetal pathophysiology derived from laboratory animals. Fetal therapy is the logical culmination of progress in fetal diagnosis. In other words, the fetus is now a patient. Now-a-days, in utero (IU) and exo utero (EU) surgical methods are popular for experimental analyses of the histogenesis of organ development. Using these surgical methods, developmental anomalies can be created and then repaired. By applying microinjection and/or fetal surgery with these methods, models of developmental anomalies such as neural tube defects, temporomandibular joint defects, hip joint defects, digit amputation, limb and digit development and regeneration, and tooth germ transplantation in the jaw could be created and later observed. After observing different types of anomalies, novel IU and EU surgical techniques would be the best approach for repairing or treating those anomalies or diseases. This review will focus on the rationale for the IU and EU creation of animal models of different organ defects or anomalies and their repair, based on analyses of organ histogenesis and pathologic observations. It will also focus in detail on the surgical techniques of both IU and EU methods.
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Männel C, Meyer L, Wilcke A, Boltze J, Kirsten H, Friederici AD. Working-memory endophenotype and dyslexia-associated genetic variant predict dyslexia phenotype. Cortex 2015; 71:291-305. [PMID: 26283516 DOI: 10.1016/j.cortex.2015.06.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 04/28/2015] [Accepted: 06/02/2015] [Indexed: 01/18/2023]
Abstract
Developmental dyslexia, a severe impairment of literacy acquisition, is known to have a neurological basis and a strong genetic background. However, effects of individual genetic variations on dyslexia-associated deficits are only moderate and call for the assessment of the genotype's impact on mediating neuro-endophenotypes by the imaging genetics approach. Using voxel-based morphometry (VBM) in German participants with and without dyslexia, we investigated gray matter changes and their association with impaired phonological processing, such as reduced verbal working memory. These endophenotypical alterations were, together with dyslexia-associated genetic variations, examined on their suitability as potential predictors of dyslexia. We identified two gray matter clusters in the left posterior temporal cortex related to verbal working memory capacity. Regional cluster differences correlated with genetic risk variants in TNFRSF1B. High-genetic-risk participants exhibit a structural predominance of auditory-association areas relative to auditory-sensory areas, which may partly compensate for deficient early auditory-sensory processing stages of verbal working memory. The reverse regional predominance observed in low-genetic-risk participants may in turn reflect reliance on these early auditory-sensory processing stages. Logistic regression analysis further supported that regional gray matter differences and genetic risk interact in the prediction of individuals' diagnostic status: With increasing genetic risk, the working-memory related structural predominance of auditory-association areas relative to auditory-sensory areas classifies participants with dyslexia versus control participants. Focusing on phonological deficits in dyslexia, our findings suggest endophenotypical changes in the left posterior temporal cortex could comprise novel pathomechanisms for verbal working memory-related processes translating TNFRSF1B genotype into the dyslexia phenotype.
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Affiliation(s)
- Claudia Männel
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Lars Meyer
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Arndt Wilcke
- Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Translational Centre for Regenerative Medicine, University of Leipzig, Leipzig, Germany
| | - Johannes Boltze
- Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Translational Centre for Regenerative Medicine, University of Leipzig, Leipzig, Germany; Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Holger Kirsten
- Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Translational Centre for Regenerative Medicine, University of Leipzig, Leipzig, Germany; Institute for Medical Informatics, Statistics, and Epidemiology (IMISE), University of Leipzig, Leipzig, Germany
| | - Angela D Friederici
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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The Roles of Genes in the Neuronal Migration and Neurite Outgrowth Network in Developmental Dyslexia: Single- and Multiple-Risk Genetic Variants. Mol Neurobiol 2015; 53:3967-3975. [PMID: 26184631 DOI: 10.1007/s12035-015-9334-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 07/01/2015] [Indexed: 01/21/2023]
Abstract
Abnormal regulation of neural migration and neurite growth is thought to be an important feature of developmental dyslexia (DD). We investigated 16 genetic variants, selected by bioinformatics analyses, in six key genes in the neuronal migration and neurite outgrowth network in a Chinese population. We first observed that KIAA0319L rs28366021, KIAA0319 rs4504469, and DOCK4 rs2074130 were significantly associated with DD risk after false discovery rate (FDR) adjustment for multiple comparisons (odds ratio (OR) = 0.672, 95 % confidence interval (CI) = 0.505-0.894, P = 0.006; OR = 1.608, 95 % CI = 1.174-2.203, P = 0.003; OR = 1.681, 95 % CI = 1.203-2.348, P = 0.002). The following classification and regression tree (CART) analysis revealed a prediction value of gene-gene interactions among DOCK4 rs2074130, KIAA0319 rs4504469, DCDC2 rs2274305, and KIAA0319L rs28366021 variants. Compared with the lowest risk carriers of the combination of rs2074130 CC, rs4504469 CC, and rs2274305 GG genotype, individuals carrying the combined genotypes of rs2074130 CC, rs4504469 CT or TT, and rs28366021 GG had a significantly increased risk for DD (OR = 2.492, 95 % CI = 1.447-4.290, P = 0.001); individuals with the combination of rs2074130 CT or TT and rs28366021 GG genotype exhibited the highest risk for DD (OR = 2.770, 95 % CI = 2.265-6.276, P = 0.000). A significant dose effect was observed among these four variants (P for trend = 0.000). In summary, this study supports the importance of single- and multiple-risk variants in this network in DD susceptibility in China.
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An assessment of gene-by-gene interactions as a tool to unfold missing heritability in dyslexia. Hum Genet 2015; 134:749-60. [DOI: 10.1007/s00439-015-1555-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/12/2015] [Indexed: 12/24/2022]
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DCDC2 polymorphism is associated with left temporoparietal gray and white matter structures during development. J Neurosci 2015; 34:14455-62. [PMID: 25339756 DOI: 10.1523/jneurosci.1216-14.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Three genes, DYX1C1, DCDC2, and KIAA0319, have been previously associated with dyslexia, neuronal migration, and ciliary function. Three polymorphisms within these genes, rs3743204 (DYX1C1), rs793842 (DCDC2), and rs6935076 (KIAA0319) have also been linked to normal variability of left temporoparietal white matter volume connecting the middle temporal cortex to the angular and supramarginal gyri. Here, we assessed whether these polymorphisms are also related to the cortical thickness of the associated regions during childhood development using a longitudinal dataset of 76 randomly selected children and young adults who were scanned up to three times each, 2 years apart. rs793842 in DCDC2 was significantly associated with the thickness of left angular and supramarginal gyri as well as the left lateral occipital cortex. The cortex was significantly thicker for T-allele carriers, who also had lower white matter volume and lower reading comprehension scores. There was a negative correlation between white matter volume and cortical thickness, but only white matter volume predicted reading comprehension 2 years after scanning. These results show how normal variability in reading comprehension is related to gene, white matter volume, and cortical thickness in the inferior parietal lobe. Possibly, the variability of gray and white matter structures could both be related to the role of DCDC2 in ciliary function, which affects both neuronal migration and axonal outgrowth.
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Im K, Raschle NM, Smith SA, Ellen Grant P, Gaab N. Atypical Sulcal Pattern in Children with Developmental Dyslexia and At-Risk Kindergarteners. Cereb Cortex 2015; 26:1138-1148. [PMID: 25576531 DOI: 10.1093/cercor/bhu305] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Developmental dyslexia (DD) is highly heritable and previous studies observed reduced cortical volume, white matter integrity, and functional alterations in left posterior brain regions in individuals with DD. The primary sulcal pattern has been hypothesized to relate to optimal organization and connections of cortical functional areas. It is determined during prenatal development and may reflect early, genetically influenced, brain development. We characterize the sulcal pattern using graph-based pattern analysis and investigate whether sulcal patterns in parieto-temporal and occipito-temporal regions are atypical in elementary school-age children with DD and pre-readers/beginning readers (preschoolers/kindergarteners) with a familial risk (elementary school-age children: n [males/females], age range = 17/11, 84-155 months; preschoolers/kindergarteners: 16/15, 59-84 months). The pattern of sulcal basin area in left parieto-temporal and occipito-temporal regions was significantly atypical (more sulcal basins of smaller size) in children with DD and further correlated with reduced reading performance on single- and nonword reading measures. A significantly atypical sulcal area pattern was also confirmed in younger preschoolers/kindergarteners with a familial risk of DD. Our results provide further support for atypical early brain development in DD and suggest that DD may originate from altered organization or connections of cortical areas in the left posterior regions.
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Affiliation(s)
- Kiho Im
- Fetal Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine.,Harvard Medical School, Boston, MA 02115, USA
| | - Nora Maria Raschle
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine.,Harvard Medical School, Boston, MA 02115, USA.,Universitäre Psychiatrische Kliniken Basel, 4056 Basel, Switzerland
| | - Sara Ashley Smith
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine
| | - P Ellen Grant
- Fetal Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine.,Deptartment of Radiology, Boston Children's Hospital, Boston, MA 02115, USA.,Harvard Medical School, Boston, MA 02115, USA
| | - Nadine Gaab
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine.,Harvard Medical School, Boston, MA 02115, USA.,Harvard Graduate School of Education, Cambridge, MA 02115, USA
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Hofmeister W, Nilsson D, Topa A, Anderlid BM, Darki F, Matsson H, Tapia Páez I, Klingberg T, Samuelsson L, Wirta V, Vezzi F, Kere J, Nordenskjöld M, Syk Lundberg E, Lindstrand A. CTNND2-a candidate gene for reading problems and mild intellectual disability. J Med Genet 2014; 52:111-22. [PMID: 25473103 DOI: 10.1136/jmedgenet-2014-102757] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Cytogenetically visible chromosomal translocations are highly informative as they can pinpoint strong effect genes even in complex genetic disorders. METHODS AND RESULTS Here, we report a mother and daughter, both with borderline intelligence and learning problems within the dyslexia spectrum, and two apparently balanced reciprocal translocations: t(1;8)(p22;q24) and t(5;18)(p15;q11). By low coverage mate-pair whole-genome sequencing, we were able to pinpoint the genomic breakpoints to 2 kb intervals. By direct sequencing, we then located the chromosome 5p breakpoint to intron 9 of CTNND2. An additional case with a 163 kb microdeletion exclusively involving CTNND2 was identified with genome-wide array comparative genomic hybridisation. This microdeletion at 5p15.2 is also present in mosaic state in the patient's mother but absent from the healthy siblings. We then investigated the effect of CTNND2 polymorphisms on normal variability and identified a polymorphism (rs2561622) with significant effect on phonological ability and white matter volume in the left frontal lobe, close to cortical regions previously associated with phonological processing. Finally, given the potential role of CTNND2 in neuron motility, we used morpholino knockdown in zebrafish embryos to assess its effects on neuronal migration in vivo. Analysis of the zebrafish forebrain revealed a subpopulation of neurons misplaced between the diencephalon and telencephalon. CONCLUSIONS Taken together, our human genetic and in vivo data suggest that defective migration of subpopulations of neuronal cells due to haploinsufficiency of CTNND2 contribute to the cognitive dysfunction in our patients.
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Affiliation(s)
- Wolfgang Hofmeister
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Alexandra Topa
- Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Fahimeh Darki
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Hans Matsson
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Isabel Tapia Páez
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Torkel Klingberg
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Lena Samuelsson
- Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Valtteri Wirta
- SciLifeLab, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Francesco Vezzi
- SciLifeLab, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Juha Kere
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden Molecular Neurology Research Program, University of Helsinki, and Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Magnus Nordenskjöld
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Elisabeth Syk Lundberg
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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44
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Kere J. The molecular genetics and neurobiology of developmental dyslexia as model of a complex phenotype. Biochem Biophys Res Commun 2014; 452:236-43. [PMID: 25078623 DOI: 10.1016/j.bbrc.2014.07.102] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 07/22/2014] [Indexed: 10/25/2022]
Abstract
Among complex disorders, those concerning neuropsychiatric phenotypes involve particular challenges compared to disorders with more easily distinguished clinical signs and measures. One such common and unusually challenging phenotype to disentangle genetically is developmental dyslexia (DD), or reading disability, defined as the inability to learn to read and write for an otherwise normally intelligent child with normal senses and educational opportunity. There is presently ample evidence for the strongly biological etiology for DD, and a dozen susceptibility genes have been suggested. Many of these genes point to common but previously unsuspected biological mechanisms, such as neuronal migration and cilia functions. I discuss here the state-of-the-art in genomic and neurobiological aspects of DD research, starting with short general background to its history.
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Affiliation(s)
- Juha Kere
- Department of Biosciences and Nutrition, Centre for Innovative Medicine, Karolinska Institutet, Stockholm, Sweden; Molecular Neurology Research Program, University of Helsinki, Folkhälsan Institute of Genetics, Helsinki, Finland.
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Eicher JD, Gruen JR. Imaging-genetics in dyslexia: connecting risk genetic variants to brain neuroimaging and ultimately to reading impairments. Mol Genet Metab 2013; 110:201-12. [PMID: 23916419 PMCID: PMC3800223 DOI: 10.1016/j.ymgme.2013.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 12/19/2022]
Abstract
Dyslexia is a common pediatric disorder that affects 5-17% of schoolchildren in the United States. It is marked by unexpected difficulties in fluent reading despite adequate intelligence, opportunity, and instruction. Classically, neuropsychologists have studied dyslexia using a variety of neurocognitive batteries to gain insight into the specific deficits and impairments in affected children. Since dyslexia is a complex genetic trait with high heritability, analyses conditioned on performance on these neurocognitive batteries have been used to try to identify associated genes. This has led to some successes in identifying contributing genes, although much of the heritability remains unexplained. Additionally, the lack of relevant human brain tissue for analysis and the challenges of modeling a uniquely human trait in animals are barriers to advancing our knowledge of the underlying pathophysiology. In vivo imaging technologies, however, present new opportunities to examine dyslexia and reading skills in a clearly relevant context in human subjects. Recent investigations have started to integrate these imaging data with genetic data in attempts to gain a more complete and complex understanding of reading processes. In addition to bridging the gap from genetic risk variant to a discernible neuroimaging phenotype and ultimately to the clinical impairments in reading performance, the use of neuroimaging phenotypes will reveal novel risk genes and variants. In this article, we briefly discuss the genetic and imaging investigations and take an in-depth look at the recent imaging-genetics investigations of dyslexia.
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Affiliation(s)
- John D. Eicher
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520
| | - Jeffrey R. Gruen
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520
- Departments of Pediatrics and Investigative Medicine, Yale University School of Medicine, New Haven, CT 06520
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Carrion-Castillo A, Franke B, Fisher SE. Molecular genetics of dyslexia: an overview. DYSLEXIA (CHICHESTER, ENGLAND) 2013; 19:214-240. [PMID: 24133036 DOI: 10.1002/dys.1464] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/02/2013] [Indexed: 05/28/2023]
Abstract
Dyslexia is a highly heritable learning disorder with a complex underlying genetic architecture. Over the past decade, researchers have pinpointed a number of candidate genes that may contribute to dyslexia susceptibility. Here, we provide an overview of the state of the art, describing how studies have moved from mapping potential risk loci, through identification of associated gene variants, to characterization of gene function in cellular and animal model systems. Work thus far has highlighted some intriguing mechanistic pathways, such as neuronal migration, axon guidance, and ciliary biology, but it is clear that we still have much to learn about the molecular networks that are involved. We end the review by highlighting the past, present, and future contributions of the Dutch Dyslexia Programme to studies of genetic factors. In particular, we emphasize the importance of relating genetic information to intermediate neurobiological measures, as well as the value of incorporating longitudinal and developmental data into molecular designs.
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Affiliation(s)
- Amaia Carrion-Castillo
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands
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47
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Rudov A, Rocchi MBL, Accorsi A, Spada G, Procopio AD, Olivieri F, Rippo MR, Albertini MC. Putative miRNAs for the diagnosis of dyslexia, dyspraxia, and specific language impairment. Epigenetics 2013; 8:1023-9. [PMID: 23949389 DOI: 10.4161/epi.26026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Disorders of human communication abilities can be classified into speech and language disorders. Speech disorders (e.g., dyspraxia) affect the sound generation and sequencing, while language disorders (e.g., dyslexia and specific language impairment, or SLI) are deficits in the encoding and decoding of language according to its rules (reading, spelling, grammar). The diagnosis of such disorders is often complicated, especially when a patient presents more than one disorder at the same time. The present review focuses on these challenges. We have combined data available from the literature with an in silico approach in an attempt to identify putative miRNAs that may have a key role in dyspraxia, dyslexia and SLI. We suggest the use of new miRNAs, which could have an important impact on the three diseases. Further, we relate those miRNAs to the axon guidance pathway and discuss possible interactions and the role of likely deregulated proteins. In addition, we describe potential differences in expressional deregulation and its role in the improvement of diagnosis. We encourage experimental investigations to test the data obtained in silico.
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Affiliation(s)
- Alexander Rudov
- Department of Biomolecular Sciences; Urbino University ''Carlo Bo''; Urbino, Italy
| | | | - Augusto Accorsi
- Department of Biomolecular Sciences; Urbino University ''Carlo Bo''; Urbino, Italy
| | - Giorgio Spada
- Dipartimento di Scienze di Base e Fondamenti; Urbino University ''Carlo Bo''; Urbino, Italy
| | | | - Fabiola Olivieri
- Department of Clinical and Molecular Sciences; Università Politecnica delle Marche; Ancona, Italy
| | - Maria Rita Rippo
- Department of Clinical and Molecular Sciences; Università Politecnica delle Marche; Ancona, Italy
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48
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Evsyukova I, Plestant C, Anton ES. Integrative mechanisms of oriented neuronal migration in the developing brain. Annu Rev Cell Dev Biol 2013; 29:299-353. [PMID: 23937349 DOI: 10.1146/annurev-cellbio-101512-122400] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The emergence of functional neuronal connectivity in the developing cerebral cortex depends on neuronal migration. This process enables appropriate positioning of neurons and the emergence of neuronal identity so that the correct patterns of functional synaptic connectivity between the right types and numbers of neurons can emerge. Delineating the complexities of neuronal migration is critical to our understanding of normal cerebral cortical formation and neurodevelopmental disorders resulting from neuronal migration defects. For the most part, the integrated cell biological basis of the complex behavior of oriented neuronal migration within the developing mammalian cerebral cortex remains an enigma. This review aims to analyze the integrative mechanisms that enable neurons to sense environmental guidance cues and translate them into oriented patterns of migration toward defined areas of the cerebral cortex. We discuss how signals emanating from different domains of neurons get integrated to control distinct aspects of migratory behavior and how different types of cortical neurons coordinate their migratory activities within the developing cerebral cortex to produce functionally critical laminar organization.
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Affiliation(s)
- Irina Evsyukova
- Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599;
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49
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DYX1C1 is required for axonemal dynein assembly and ciliary motility. Nat Genet 2013; 45:995-1003. [PMID: 23872636 DOI: 10.1038/ng.2707] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/24/2013] [Indexed: 11/08/2022]
Abstract
DYX1C1 has been associated with dyslexia and neuronal migration in the developing neocortex. Unexpectedly, we found that deleting exons 2-4 of Dyx1c1 in mice caused a phenotype resembling primary ciliary dyskinesia (PCD), a disorder characterized by chronic airway disease, laterality defects and male infertility. This phenotype was confirmed independently in mice with a Dyx1c1 c.T2A start-codon mutation recovered from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. Morpholinos targeting dyx1c1 in zebrafish also caused laterality and ciliary motility defects. In humans, we identified recessive loss-of-function DYX1C1 mutations in 12 individuals with PCD. Ultrastructural and immunofluorescence analyses of DYX1C1-mutant motile cilia in mice and humans showed disruptions of outer and inner dynein arms (ODAs and IDAs, respectively). DYX1C1 localizes to the cytoplasm of respiratory epithelial cells, its interactome is enriched for molecular chaperones, and it interacts with the cytoplasmic ODA and IDA assembly factor DNAAF2 (KTU). Thus, we propose that DYX1C1 is a newly identified dynein axonemal assembly factor (DNAAF4).
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50
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Platt MP, Adler WT, Mehlhorn AJ, Johnson GC, Wright KA, Choi RT, Tsang WH, Poon MW, Yeung SY, Waye MMY, Galaburda AM, Rosen GD. Embryonic disruption of the candidate dyslexia susceptibility gene homolog Kiaa0319-like results in neuronal migration disorders. Neuroscience 2013; 248:585-93. [PMID: 23831424 DOI: 10.1016/j.neuroscience.2013.06.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 02/04/2023]
Abstract
Developmental dyslexia, the most common childhood learning disorder, is highly heritable, and recent studies have identified KIAA0319-Like (KIAA0319L) as a candidate dyslexia susceptibility gene at the 1p36-34 (DYX8) locus. In this experiment, we investigated the anatomical effects of knocking down this gene during rat corticogenesis. Cortical progenitor cells were transfected using in utero electroporation on embryonic day (E) 15.5 with plasmids encoding either: (1) Kiaa0319l small hairpin RNA (shRNA), (2) an expression construct for human KIAA0319L, (3) Kiaa0319l shRNA+KIAA0319L expression construct (rescue), or (4) controls (scrambled Kiaa0319l shRNA or empty expression vector). Mothers were injected with 5-bromo-2-deoxyuridine (BrdU) at either E13.5, E15.5, or E17.5. Disruption of Kiaa0319l function (by knockdown, overexpression, or rescue) resulted in the formation of large nodular periventricular heterotopia in approximately 25% of the rats, which can be seen as early as postnatal day 1. Only a small subset of heterotopic neurons had been transfected, indicating non-cell autonomous effects of the transfection. Most heterotopic neurons were generated in mid- to late-gestation, and laminar markers suggest that they were destined for upper cortical laminae. Finally, we found that transfected neurons in the cerebral cortex were located in their expected laminae. These results indicate that KIAA0319L is the fourth of four candidate dyslexia susceptibility genes that is involved in neuronal migration, which supports the association of abnormal neuronal migration with developmental dyslexia.
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Affiliation(s)
- M P Platt
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - W T Adler
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - A J Mehlhorn
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - G C Johnson
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - K A Wright
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - R T Choi
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - W H Tsang
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - M W Poon
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - S Y Yeung
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - M M Y Waye
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - A M Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - G D Rosen
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
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