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Chapman NH, Navas PA, Dorschner MO, Mehaffey M, Wigg KG, Price KM, Naumova OY, Kerr EN, Guger SL, Lovett MW, Grigorenko EL, Berninger V, Barr CL, Wijsman EM, Raskind WH. Targeted analysis of dyslexia-associated regions on chromosomes 6, 12 and 15 in large multigenerational cohorts. PLoS One 2025; 20:e0324006. [PMID: 40424442 PMCID: PMC12112411 DOI: 10.1371/journal.pone.0324006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 04/19/2025] [Indexed: 05/29/2025] Open
Abstract
Dyslexia is a common learning impairment with a genetic basis that affects word reading and spelling. An increasing list of loci and genes have been implicated, but analyses to-date have investigated only limited genomic variation within each locus with no confirmed pathogenic variants identified. Our study is the first to comprehensively sequence both coding and cis-acting regulatory regions of such genes in a large study sample. In a collection of >2000 participants in families from three independent sites, we performed targeted capture and comprehensive sequencing of all exons and some regulatory elements of five candidate risk genes (DNAAF4, CYP19A1, DCDC2, KIAA0319 and GRIN2B) for which prior evidence for a role in dyslexia exists from more than one sample. We evaluated evidence for association in each of six dyslexia-related quantitative phenotypes (traits) using both individual common single nucleotide polymorphisms and aggregated rare variants. We detected no promoter alterations and few deleterious variants in the coding exons, none of which showed evidence of association with any trait. Single variant and aggregate testing of DNAAF4 failed to detect significant evidence of association with any of the traits. The other four genes provided evidence of association with one or more traits. A common variant downstream of CYP19A1 showed significant evidence of association with multiple traits with or without verbal IQ (VIQ) adjustment. A haplotype that stretches from the downstream region of KIAA0319 to the second intron of DCDC2 was associated with reduced performance on timed real word reading. Finally, rare exonic variants in GRIN2B were associated with performance on spelling, with or without adjustment for VIQ. Our findings from this large-scale sequencing study complement those from genome-wide association studies, argue against the causative involvement of large-effect coding variants in these five candidate genes, support a multigenic etiology, and suggest a role of transcriptional regulation.
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Affiliation(s)
- Nicola H. Chapman
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Patrick A. Navas
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michael O. Dorschner
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michele Mehaffey
- Department of Pediatrics, Division of Pediatric Genetics, Pediatric Genetics, University of Washington, Seattle, Washington, United States of America
| | - Karen G. Wigg
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kaitlyn M. Price
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Oxana Y. Naumova
- Department of Psychology, University of Houston, Houston, Texas, United States of America
| | - 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
| | - 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
| | - Elena L. Grigorenko
- Department of Psychology, University of Houston, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States of America
| | - Virginia Berninger
- Department of Educational Psychology, University of Washington, Seattle, Washington, United States of America
| | - Cathy L. Barr
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Educational Psychology, University of Washington, Seattle, Washington, United States of America
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Ellen M. Wijsman
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Wendy H. Raskind
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, Washington, United States of America
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Li M, DeMille MMC, Lovett MW, Bosson-Heenan J, Frijters JC, Gruen JR. Phonological awareness mediates the relationship between DCDC2 and reading performance with home environment. NPJ SCIENCE OF LEARNING 2024; 9:36. [PMID: 38702345 PMCID: PMC11068914 DOI: 10.1038/s41539-024-00247-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 04/11/2024] [Indexed: 05/06/2024]
Abstract
Proficient reading requires critical phonological processing skill that interacts with both genetic and environmental factors. However, the precise nature of the relationships between phonological processing and genetic and environmental factors are poorly understood. We analyzed data from the Genes, Reading and Dyslexia (GRaD) Study on 1419 children ages 8-15 years from African-American and Hispanic-American family backgrounds living in North America. The analyses showed that phonological awareness mediated the relationship between DCDC2-READ1 and reading outcomes when parental education and socioeconomic status was low. The association between READ1 and reading performance is complex, whereby mediation by phonological awareness was significantly moderated by both parental education and socioeconomic status. These results show the importance of home environment and phonological skills when determining associations between READ1 and reading outcomes. This will be an important consideration in the development of genetic screening for risk of reading disability.
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Affiliation(s)
- Miao Li
- Department of Curriculum and Instruction, College of Education, University of Houston, Houston, TX, USA.
| | - Mellissa M C DeMille
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Maureen W Lovett
- Neurosciences and Mental Health Program, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Joan Bosson-Heenan
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Jan C Frijters
- Department of Child and Youth Studies, Faculty of Social Sciences, Brock University, St. Catharines, ON, Canada
| | - Jeffrey R Gruen
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA.
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Rinne N, Wikman P, Sahari E, Salmi J, Einarsdóttir E, Kere J, Alho K. Developmental dyslexia susceptibility genes DNAAF4, DCDC2, and NRSN1 are associated with brain function in fluently reading adolescents and young adults. Cereb Cortex 2024; 34:bhae144. [PMID: 38610086 PMCID: PMC11014888 DOI: 10.1093/cercor/bhae144] [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: 10/11/2023] [Revised: 03/16/2024] [Accepted: 03/17/2024] [Indexed: 04/14/2024] Open
Abstract
Reading skills and developmental dyslexia, characterized by difficulties in developing reading skills, have been associated with brain anomalies within the language network. Genetic factors contribute to developmental dyslexia risk, but the mechanisms by which these genes influence reading skills remain unclear. In this preregistered study (https://osf.io/7sehx), we explored if developmental dyslexia susceptibility genes DNAAF4, DCDC2, NRSN1, and KIAA0319 are associated with brain function in fluently reading adolescents and young adults. Functional MRI and task performance data were collected during tasks involving written and spoken sentence processing, and DNA sequence variants of developmental dyslexia susceptibility genes previously associated with brain structure anomalies were genotyped. The results revealed that variation in DNAAF4, DCDC2, and NRSN1 is associated with brain activity in key language regions: the left inferior frontal gyrus, middle temporal gyrus, and intraparietal sulcus. Furthermore, NRSN1 was associated with task performance, but KIAA0319 did not yield any significant associations. Our findings suggest that individuals with a genetic predisposition to developmental dyslexia may partly employ compensatory neural and behavioral mechanisms to maintain typical task performance. Our study highlights the relevance of these developmental dyslexia susceptibility genes in language-related brain function, even in individuals without developmental dyslexia, providing valuable insights into the genetic factors influencing language processing.
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Affiliation(s)
- Nea Rinne
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
| | - Patrik Wikman
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
| | - Elisa Sahari
- Department of Psychology and Speech-Language Pathology, University of Turku, Assistentinkatu 7, 20500 Turku, Finland
| | - Juha Salmi
- Department of Neuroscience and Biomedical Engineering, Otakaari 3, Aalto University, (AALTO), P.O. BOX 00076, Espoo, Finland
| | - Elisabet Einarsdóttir
- Science for Life Laboratory, Department of Gene Technology, KTH-Royal Institute of Technology, SE-171 21, Solna, Sweden
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, H7 Medicin, Huddinge, Sweden
- Folkhälsan Research Center, and Stem Cells and Metabolism Research Program (STEMM), University of Helsinki, PL 63, Haartmaninkatu 8, Helsinki, Finland
| | - Kimmo Alho
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
- Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University, Espoo, Finland
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Li M, DeMille M, Lovett M, Bosson-Heenan J, Frijters J, Gruen J. Phonological Awareness Mediates the Relationship between DCDC2 and Reading Performance with the Influence of Home Environment. RESEARCH SQUARE 2023:rs.3.rs-2786924. [PMID: 37214935 PMCID: PMC10197759 DOI: 10.21203/rs.3.rs-2786924/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Proficient reading requires critical phonological processing skill that interact with both genetic and environmental factors. However, the precise nature of the relationships between phonological processing and genetic and environmental factors are poorly understood. We analyzed data from the Genes, Reading and Dyslexia (GRaD) Study on 1,419 children ages 8 to 14 years from African-American and Hispanic-American family backgrounds living in North America. The analyses showed that phonological awareness mediated the relationship between DCDC2-READ1 and reading outcomes when parental education and socioeconomic status was low. The association between READ1 and reading performance is complex, whereby mediation by phonological awareness was significantly moderated by both parental education and socioeconomic status. These results show the importance of home environment and phonological skills when determining associations between READ1 and reading outcomes. This will be an important consideration in the development of genetic screening for risk of reading disability.
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Affiliation(s)
- Miao Li
- University of Houston/Harvard University
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5
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Gabel LA, Battison A, Truong DT, Lindström ER, Voss K, Yu YC, Roongruengratanakul S, Shyntassov K, Riebesell S, Toumanios N, Nielsen-Pheiffer CM, Paniagua S, Gruen JR. Orthographic Depth May Influence the Degree of Severity of Maze Learning Performance in Children at Risk for Reading Disorder. Dev Neurosci 2022; 44:651-670. [PMID: 36223729 PMCID: PMC9928771 DOI: 10.1159/000527480] [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: 06/24/2022] [Accepted: 10/06/2022] [Indexed: 11/19/2022] Open
Abstract
Reading disability (RD), which affects between 5 and 17% of the population worldwide, is the most prevalent form of learning disability, and is associated with underactivation of a universal reading network in children. However, recent research suggests there are differences in learning rates on cognitive predictors of reading performance, as well as differences in activation patterns within the reading neural network, based on orthographic depth (i.e., transparent/shallow vs. deep/opaque orthographies) in children with RD. Recently, we showed that native English-speaking children with RD exhibit impaired performance on a maze learning task that taps into the same neural networks that are activated during reading. In addition, we demonstrated that genetic risk for RD strengthens the relationship between reading impairment and maze learning performance. However, it is unclear whether the results from these studies can be broadly applied to children from other language orthographies. In this study, we examined whether low reading skill was associated with poor maze learning performance in native English-speaking and native German-speaking children, and the influence of genetic risk for RD on cognition and behavior. In addition, we investigated the link between genetic risk and performance on this task in an orthographically diverse sample of children attending an English-speaking international school in Germany. The results from our data suggest that children with low reading skill, or with a genetic risk for reading impairment, exhibit impaired performance on the maze learning task, regardless of orthographic depth. However, these data also suggest that orthographic depth influences the degree of impairment on this task. The maze learning task requires the involvement of various cognitive processes and neural networks that underlie reading, but is not influenced by potential differences in reading experience due to lack of text or oral reporting. As a fully automated tool, it does not require specialized training to administer, and current results suggest it may be a practicable screening tool for early identification of reading impairment across orthographies.
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Affiliation(s)
- Lisa A. Gabel
- Department of Psychology, Lafayette College, Easton, PA
- Program in Neuroscience, Lafayette College, Easton, PA
| | | | | | - Esther R. Lindström
- Department of Education and Human Services, Lehigh University, Bethlehem, PA
| | - Kelsey Voss
- Program in Neuroscience, Lafayette College, Easton, PA
| | - Yih-Choung Yu
- Department of Electrical & Computer Engineering, Lafayette College, Easton, PA
| | | | | | | | | | | | - Steven Paniagua
- Department of Genetics, Yale School of Medicine, New Haven, CT
| | - Jeffrey R. Gruen
- Department of Genetics, Yale School of Medicine, New Haven, CT
- Department of Pediatrics, Yale School of Medicine, New Haven, CT
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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: 6] [Impact Index Per Article: 1.5] [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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Gabel LA, Voss K, Johnson E, Lindström ER, Truong DT, Murray EM, Cariño K, Nielsen CM, Paniagua S, Gruen JR. Identifying Dyslexia: Link between Maze Learning and Dyslexia Susceptibility Gene, DCDC2, in Young Children. Dev Neurosci 2021; 43:116-133. [PMID: 34186533 DOI: 10.1159/000516667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/20/2021] [Indexed: 12/29/2022] Open
Abstract
Dyslexia is a common learning disability that affects processing of written language despite adequate intelligence and educational background. If learning disabilities remain untreated, a child may experience long-term social and emotional problems, which influence future success in all aspects of their life. Dyslexia has a 60% heritability rate, and genetic studies have identified multiple dyslexia susceptibility genes (DSGs). DSGs, such as DCDC2, are consistently associated with the risk and severity of reading disability (RD). Altered neural connectivity within temporoparietal regions of the brain is associated with specific variants of DSGs in individuals with RD. Genetically altering DSG expression in mice results in visual and auditory processing deficits as well as neurophysiological and neuroanatomical disruptions. Previously, we demonstrated that learning deficits associated with RD can be translated across species using virtual environments. In this 2-year longitudinal study, we demonstrate that performance on a virtual Hebb-Williams maze in pre-readers is able to predict future reading impairment, and the genetic risk strengthens, but is not dependent on, this relationship. Due to the lack of oral reporting and use of letters, this easy-to-use tool may be particularly valuable in a remote working environment as well as working with vulnerable populations such as English language learners.
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Affiliation(s)
- Lisa A Gabel
- Department of Psychology, Lafayette College, Easton, Pennsylvania, USA.,Program in Neuroscience, Lafayette College, Easton, Pennsylvania, USA
| | - Kelsey Voss
- Program in Neuroscience, Lafayette College, Easton, Pennsylvania, USA
| | - Evelyn Johnson
- Department of Special Education, Boise State University, Boise, Idaho, USA
| | - Esther R Lindström
- Department of Education and Human Services, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Dongnhu T Truong
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Erin M Murray
- Program in Neuroscience, Lafayette College, Easton, Pennsylvania, USA
| | - Karla Cariño
- Program in Neuroscience, Lafayette College, Easton, Pennsylvania, USA
| | - Christiana M Nielsen
- Department of Education and Human Services, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Steven Paniagua
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeffrey R Gruen
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
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Kalnak N, Sahlén B. Description and prediction of reading decoding skills in Swedish children with Developmental Language Disorder. LOGOP PHONIATR VOCO 2020; 47:84-91. [PMID: 33140677 DOI: 10.1080/14015439.2020.1839964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AIM Research is lacking in terms of reading decoding skills among clinical samples of Swedish-speaking children with Developmental Language Disorder (DLD). METHOD The present cross-sectional study included a sample of 61 children (8-12 years) with DLD attending school language units, years 1 to 5. Our purpose was to study reading decoding skills and predictors for decoding, such as a phonological processing skill (nonword repetition), working memory, and a family history of literacy problems. RESULTS The results on a combined measure of the word and nonword decoding indicated that only 18% of the children had age-adequate decoding skills. The proportion of age-adequate decoders did not change noticeably with the school year. The participants' decoding skills showed larger deviations to test norm means with higher school years. Hierarchical regression analysis showed that the best predictors of decoding skills were measures of working memory and nonword repetition, followed by school year. These factors significantly contributed to the variance in decoding among our sample of children with DLD. A family history of literacy problems made no contribution to the variance. Conclusions: The findings emphasize the necessity of assessing and following up on literacy development in children with DLD.
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Affiliation(s)
- Nelli Kalnak
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Child and Adolescent Psychiatry, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Birgitta Sahlén
- Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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Lancaster HS, Liu X, Dinu V, Li J. Identifying interactive biological pathways associated with reading disability. Brain Behav 2020; 10:e01735. [PMID: 32596987 PMCID: PMC7428467 DOI: 10.1002/brb3.1735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/01/2020] [Accepted: 06/07/2020] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Past research has suggested that reading disability is a complex disorder involving genetic and environment contributions, as well as gene-gene and gene-environment interaction, but to date little is known about the underlying mechanisms. METHOD Using the Avon Longitudinal Study of Parents and Children, we assessed the contributions of genetic, demographic, and environmental variables on case-control status using machine learning. We investigated the functional interactions between genes using pathway and network analysis. RESULTS Our results support a systems approach to studying the etiology of reading disability with many genes (e.g., RAPGEF2, KIAA0319, DLC1) and biological pathways (e.g., neuron migration, positive regulation of dendrite regulation, nervous system development) interacting with each other. We found that single nucleotide variants within genes often had opposite effects and that enriched biological pathways were mediated by neuron migration. We also identified behavioral (i.e., receptive language, nonverbal intelligence, and vocabulary), demographic (i.e., mother's highest education), and environmental (i.e., birthweight) factors that influenced case-control status when accounting for genetic information. DISCUSSION The behavioral and demographic factors were suggested to be protective against reading disability status, while birthweight conveyed risk. We provided supporting evidence that reading disability has a complex biological and environmental etiology and that there may be a shared genetic and neurobiological architecture for reading (dis)ability.
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Affiliation(s)
- Hope Sparks Lancaster
- College of Health SolutionsArizona State UniversityTempeAZUSA
- Department of Computing, Informatics, and Decision Systems EngineeringSchools of EngineeringArizona State UniversityTempeAZUSA
| | - Xiaonan Liu
- Department of Computing, Informatics, and Decision Systems EngineeringSchools of EngineeringArizona State UniversityTempeAZUSA
| | - Valentin Dinu
- College of Health SolutionsArizona State UniversityTempeAZUSA
| | - Jing Li
- School of Industrial and Systems EngineeringGeorgia Institute of TechnologyAtlantaGAUSA
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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: 13] [Impact Index Per Article: 2.2] [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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11
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Li M, Malins JG, DeMille MMC, Lovett MW, Truong DT, Epstein K, Lacadie C, Mehta C, Bosson-Heenan J, Gruen JR, Frijters JC. A molecular-genetic and imaging-genetic approach to specific comprehension difficulties in children. NPJ SCIENCE OF LEARNING 2018; 3:20. [PMID: 30631481 PMCID: PMC6249284 DOI: 10.1038/s41539-018-0034-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 08/08/2018] [Accepted: 08/21/2018] [Indexed: 06/09/2023]
Abstract
Children with poor reading comprehension despite typical word reading skills were examined using neuropsychological, genetic, and neuroimaging data collected from the Genes, Reading and Dyslexia Study of 1432 Hispanic American and African American children. This unexpected poor comprehension was associated with profound deficits in vocabulary, when compared to children with comprehension skills consistent with their word reading. Those with specific comprehension difficulties were also more likely to have RU2Short alleles of READ1 regulatory variants of DCDC2, strongly associated with reading and language difficulties. Subjects with RU2Short alleles showed stronger resting state functional connectivity between the right insula/inferior frontal gyrus and the right supramarginal gyrus, even after controlling for potentially confounding variables including genetic ancestry and socioeconomic status. This multi-disciplinary approach advances the current understanding of specific reading comprehension difficulties, and suggests the need for interventions that are more appropriately tailored to the specific comprehension deficits of this group of children.
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Affiliation(s)
- Miao Li
- Department of Curriculum and Instruction, College of Education, University of Houston, Houston, TX USA
- Graduate School of Education, Harvard University, Cambridge, MA USA
| | - Jeffrey G. Malins
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
- Haskins Laboratories, New Haven, CT USA
| | | | - Maureen W. Lovett
- Neurosciences and Mental Health Program, Learning Disabilities Research Program, The Hospital for Sick Children, University of Toronto, Toronto, ON Canada
| | - Dongnhu T. Truong
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
| | - Katherine Epstein
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
| | - Cheryl Lacadie
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT USA
| | - Chintan Mehta
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
| | - Joan Bosson-Heenan
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
| | - Jeffrey R. Gruen
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT USA
- Department of Genetics and the Investigative Medicine Program, Yale University School of Medicine, New Haven, CT USA
| | - Jan C. Frijters
- Faculty of Social Sciences, Department of Child and Youth Studies, Brock University, St. Catharines, ON Canada
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12
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Waye MMY, Poo LK, Ho CSH. Study of Genetic Association With DCDC2 and Developmental Dyslexia in Hong Kong Chinese Children. Clin Pract Epidemiol Ment Health 2017; 13:104-114. [PMID: 29081827 PMCID: PMC5633722 DOI: 10.2174/1745017901713010104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/21/2017] [Accepted: 07/25/2017] [Indexed: 11/30/2022]
Abstract
Background: Doublecortin domain-containing 2 (DCDC2) is a doublecortin domain-containing gene family member and the doublecortin domain has been demonstrated to bind to tubulin and enhance microtubule polymerization. It has been associated with developmental dyslexia and this protein family member is thought to function in neuronal migration where it may affect the signaling of primary cilia. Objectives: The objective of the study is to find out if there is any association of genetic variants of DCDC2 with developmental dyslexia in Chinese children from Hong Kong. Methods: The dyslexic children were diagnosed as developmental dyslexia (DD) using the Hong Kong Test of Specific Learning Difficulties in Reading and Writing (HKT-SpLD) by the Department of Health, Hong Kong. Saliva specimens were collected and their genotypes of DCDC2 were studied by DNA sequencing or TaqMan Real Time PCR Assays. Results: The most significant marker is rs6940827 which is associated with DD with nominal p-value (0.011). However, this marker did not remain significant after multiple testing corrections and the adjusted p-value from permutation test was 0.1329. Using sliding window haplotype analysis, several haplotypes were found to be nominally associated with DD. The smallest nominal p values was 0.0036 (rs2996452-rs1318700, C-A). However, none of the p values could withstand the multiple testing corrections. Conclusion: Despite early findings that DCDC2 is a strong candidate for developmental dyslexia and that some of the genetic variants have been linked to brain structure and functions, our findings showed that DCDC2 is not strongly associated with dyslexia.
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Affiliation(s)
- Mary M Y Waye
- The Nethersole School of Nursing, The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong
| | - Lim K Poo
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong
| | - Connie S-H Ho
- Department of Psychology, The University of Hong Kong, Hong Kong
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13
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Abstract
Over the past 50 years, research on children and adults with learning disabilities has seen significant advances. Neuropsychological research historically focused on the administration of tests sensitive to brain dysfunction to identify putative neural mechanisms underlying learning disabilities that would serve as the basis for treatment. Led by research on classifying and identifying learning disabilities, four pivotal changes in research paradigms have produced a contemporary scientific, interdisciplinary, and international understanding of these disabilities. These changes are (1) the emergence of cognitive science, (2) the development of quantitative and molecular genetics, (3) the advent of noninvasive structural and functional neuroimaging, and (4) experimental trials of interventions focused on improving academic skills and addressing comorbid conditions. Implications for practice indicate a need to move neuropsychological assessment away from a primary focus on systematic, comprehensive assessment of cognitive skills toward more targeted performance-based assessments of academic achievement, comorbid conditions, and intervention response that lead directly to evidence-based treatment plans. Future research will continue to cross disciplinary boundaries to address questions regarding the interaction of neurobiological and contextual variables, the importance of individual differences in treatment response, and an expanded research base on (a) the most severe cases, (b) older people with LDs, and (c) domains of math problem solving, reading comprehension, and written expression. (JINS, 2017, 23, 930-940).
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14
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Mascheretti S, Trezzi V, Giorda R, Boivin M, Plourde V, Vitaro F, Brendgen M, Dionne G, Marino C. Complex effects of dyslexia risk factors account for ADHD traits: evidence from two independent samples. J Child Psychol Psychiatry 2017; 58:75-82. [PMID: 27501527 DOI: 10.1111/jcpp.12612] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/13/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Developmental dyslexia (DD) and attention deficit/hyperactivity disorder (ADHD) are among the most common neurodevelopmental disorders, whose etiology involves multiple risk factors. DD and ADHD co-occur in the same individuals much more often than would be expected by chance. Several studies have found significant bivariate heritability, and specific genes associated with either DD or ADHD have been investigated for association in the other disorder. Moreover, there are likely to be gene-by-gene and gene-by-environment interaction effects (G × G and G × E, respectively) underlying the comorbidity between DD and ADHD. We investigated the pleiotropic effects of 19 SNPs spanning five DD genes (DYX1C1, DCDC2, KIAA0319, ROBO1, and GRIN2B) and seven DD environmental factors (smoke, miscarriage, birth weight, breastfeeding, parental age, socioeconomic status, and parental education) for main, either (a) genetic or (b) environmental, (c) G × G, and (d) G × E upon inattention and hyperactivity/impulsivity. We then attempted replication of these findings in an independent twin cohort. METHODS Marker-trait association was analyzed by implementing the Quantitative Transmission Disequilibrium Test (QTDT). Environmental associations were tested by partial correlations. G × G were investigated by a general linear model equation and a family-based association test. G × E were analyzed through a general test for G × E in sib pair-based association analysis of quantitative traits. RESULTS DCDC2-rs793862 was associated with hyperactivity/impulsivity via G × G (KIAA0319) and G × E (miscarriage). Smoke was significantly correlated with hyperactivity/impulsivity. We replicated the DCDC2 × KIAA0319 interaction upon hyperactivity/impulsivity in the twin cohort. CONCLUSIONS DD genetic (DCDC2) and environmental factors (smoke and miscarriage) underlie ADHD traits supporting a potential pleiotropic effect.
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Affiliation(s)
- Sara Mascheretti
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Vittoria Trezzi
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Roberto Giorda
- Molecular Biology Lab, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Michel Boivin
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada.,Institute of Genetic, Neurobiological, and Social Foundations of Child Development, Tomsk State University, Tomsk, Russian Federation
| | - Vickie Plourde
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada
| | - Frank Vitaro
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Department of Psycho-Education, GRIP, University of Montreal, Montreal, QC, Canada
| | - Mara Brendgen
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada
| | - Ginette Dionne
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada
| | - Cecilia Marino
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy.,Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
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15
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Eicher JD, Montgomery AM, Akshoomoff N, Amaral DG, Bloss CS, Libiger O, Schork NJ, Darst BF, Casey BJ, Chang L, Ernst T, Frazier J, Kaufmann WE, Keating B, Kenet T, Kennedy D, Mostofsky S, Murray SS, Sowell ER, Bartsch H, Kuperman JM, Brown TT, Hagler DJ, Dale AM, Jernigan TL, Gruen JR. Dyslexia and language impairment associated genetic markers influence cortical thickness and white matter in typically developing children. Brain Imaging Behav 2016; 10:272-82. [PMID: 25953057 PMCID: PMC4639472 DOI: 10.1007/s11682-015-9392-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dyslexia and language impairment (LI) are complex traits with substantial genetic components. We recently completed an association scan of the DYX2 locus, where we observed associations of markers in DCDC2, KIAA0319, ACOT13, and FAM65B with reading-, language-, and IQ-related traits. Additionally, the effects of reading-associated DYX3 markers were recently characterized using structural neuroimaging techniques. Here, we assessed the neuroimaging implications of associated DYX2 and DYX3 markers, using cortical volume, cortical thickness, and fractional anisotropy. To accomplish this, we examined eight DYX2 and three DYX3 markers in 332 subjects in the Pediatrics Imaging Neurocognition Genetics study. Imaging-genetic associations were examined by multiple linear regression, testing for influence of genotype on neuroimaging. Markers in DYX2 genes KIAA0319 and FAM65B were associated with cortical thickness in the left orbitofrontal region and global fractional anisotropy, respectively. KIAA0319 and ACOT13 were suggestively associated with overall fractional anisotropy and left pars opercularis cortical thickness, respectively. DYX3 markers showed suggestive associations with cortical thickness and volume measures in temporal regions. Notably, we did not replicate association of DYX3 markers with hippocampal measures. In summary, we performed a neuroimaging follow-up of reading-, language-, and IQ-associated DYX2 and DYX3 markers. DYX2 associations with cortical thickness may reflect variations in their role in neuronal migration. Furthermore, our findings complement gene expression and imaging studies implicating DYX3 markers in temporal regions. These studies offer insight into where and how DYX2 and DYX3 risk variants may influence neuroimaging traits. Future studies should further connect the pathways to risk variants associated with neuroimaging/neurocognitive outcomes.
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Affiliation(s)
- John D Eicher
- Department of Genetics, Yale University, New Haven, CT, 06520, USA
| | - Angela M Montgomery
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Natacha Akshoomoff
- Center for Human Development, University of California, La Jolla, San Diego, CA, 92037, USA
- Department of Psychiatry, University of California, La Jolla, San Diego, CA, 92037, USA
| | - David G Amaral
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, 95817, USA
| | - Cinnamon S Bloss
- Scripps Genomic Medicine, Scripps Health, Scripps Translational Science Institute, La Jolla, CA, 92037, USA
| | - Ondrej Libiger
- Scripps Genomic Medicine, Scripps Health, Scripps Translational Science Institute, La Jolla, CA, 92037, USA
| | - Nicholas J Schork
- Scripps Genomic Medicine, Scripps Health, Scripps Translational Science Institute, La Jolla, CA, 92037, USA
| | - Burcu F Darst
- Scripps Genomic Medicine, Scripps Health, Scripps Translational Science Institute, La Jolla, CA, 92037, USA
| | - B J Casey
- Sackler Institute for Developmental Psychobiology, Weil Cornell Medical College, New York, NY, 10065, USA
| | - Linda Chang
- Department of Medicine, Queen's Medical Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Thomas Ernst
- Department of Medicine, Queen's Medical Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Jean Frazier
- Department of Psychiatry, University of Massachusetts Medical School, Boston, MA, 01655, USA
| | - Walter E Kaufmann
- Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD, 21205, USA
- Department of Neurology, Harvard Medical School, Children's Hospital Boston, Boston, MA, 02115, USA
| | - Brian Keating
- Department of Medicine, Queen's Medical Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Tal Kenet
- Department of Neurology and Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - David Kennedy
- Department of Psychiatry, University of Massachusetts Medical School, Boston, MA, 01655, USA
| | - Stewart Mostofsky
- Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD, 21205, USA
| | - Sarah S Murray
- Scripps Genomic Medicine, Scripps Health, Scripps Translational Science Institute, La Jolla, CA, 92037, USA
| | - Elizabeth R Sowell
- Department of Pediatrics, University of Southern California, Los Angeles, CA, 90027, USA
- Developmental Cognitive Neuroimaging Laboratory Children's Hospital, Los Angeles, CA, 90027, USA
| | - Hauke Bartsch
- Multimodal Imaging Laboratory, University of California, La Jolla, San Diego, CA, 92037, USA
| | - Joshua M Kuperman
- Multimodal Imaging Laboratory, University of California, La Jolla, San Diego, CA, 92037, USA
- Department of Neurosciences, University of California, La Jolla, San Diego, CA, 92037, USA
| | - Timothy T Brown
- Center for Human Development, University of California, La Jolla, San Diego, CA, 92037, USA
- Multimodal Imaging Laboratory, University of California, La Jolla, San Diego, CA, 92037, USA
- Department of Neurosciences, University of California, La Jolla, San Diego, CA, 92037, USA
| | - Donald J Hagler
- Multimodal Imaging Laboratory, University of California, La Jolla, San Diego, CA, 92037, USA
- Radiology University of California, La Jolla, San Diego, CA, 92037, USA
| | - Anders M Dale
- Department of Psychiatry, University of California, La Jolla, San Diego, CA, 92037, USA
- Multimodal Imaging Laboratory, University of California, La Jolla, San Diego, CA, 92037, USA
- Department of Neurosciences, University of California, La Jolla, San Diego, CA, 92037, USA
- Radiology University of California, La Jolla, San Diego, CA, 92037, USA
- Cognitive Science University of California, La Jolla, San Diego, CA, 92037, USA
| | - Terry L Jernigan
- Center for Human Development, University of California, La Jolla, San Diego, CA, 92037, USA
- Department of Psychiatry, University of California, La Jolla, San Diego, CA, 92037, USA
- Radiology University of California, La Jolla, San Diego, CA, 92037, USA
- Cognitive Science University of California, La Jolla, San Diego, CA, 92037, USA
| | - Jeffrey R Gruen
- Department of Genetics, Yale University, New Haven, CT, 06520, USA.
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, 06520, USA.
- Department of Investigative, School of Medicine, Medicine Yale University, New Haven, CT, 06520, USA.
- Department of Pediatrics, Genetics, and Investigative Medicine, Yale Child Health Research Center, 464 Congress Avenue, New Haven, CT, 06520-8081, USA.
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16
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Kong R, Song RR. [Research advances in susceptible genes for developmental dyslexia in children]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2016; 18:1308-1312. [PMID: 27974128 PMCID: PMC7403085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/24/2016] [Indexed: 12/16/2023]
Abstract
Developmental dyslexia in children is one of the neurodevelopmental disorders and is affected by various susceptible genes. In recent years, researchers have found some susceptible genes for dyslexia via chromosome analysis, genome-wide association studies, association analysis, gene function research, neuroimaging, and neurophysiological techniques. This article reviews the research advances in susceptible genes for developmental dyslexia, and with the study on susceptible genes for dyslexia, it lays a foundation for in-depth studies on the "gene-brain-behavior" level and provides scientific clues for exploring etiology and pathogenesis of dyslexia.
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Affiliation(s)
- Rui Kong
- Department of Maternal and Child Health Care, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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17
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Kong R, Song RR. [Research advances in susceptible genes for developmental dyslexia in children]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2016; 18:1308-1312. [PMID: 27974128 PMCID: PMC7403085 DOI: 10.7499/j.issn.1008-8830.2016.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Developmental dyslexia in children is one of the neurodevelopmental disorders and is affected by various susceptible genes. In recent years, researchers have found some susceptible genes for dyslexia via chromosome analysis, genome-wide association studies, association analysis, gene function research, neuroimaging, and neurophysiological techniques. This article reviews the research advances in susceptible genes for developmental dyslexia, and with the study on susceptible genes for dyslexia, it lays a foundation for in-depth studies on the "gene-brain-behavior" level and provides scientific clues for exploring etiology and pathogenesis of dyslexia.
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Affiliation(s)
- Rui Kong
- Department of Maternal and Child Health Care, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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18
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Gunnarsson B, Jónsdóttir GA, Björnsdóttir G, Konte B, Sulem P, Kristmundsdóttir S, Kehr B, Gústafsson Ó, Helgason H, Iordache PD, Ólafsson S, Frigge ML, Þorleifsson G, Arnarsdóttir S, Stefánsdóttir B, Giegling I, Djurovic S, Sundet KS, Espeseth T, Melle I, Hartmann AM, Thorsteinsdottir U, Kong A, Guðbjartsson DF, Ettinger U, Andreassen OA, Dan Rujescu, Halldórsson JG, Stefánsson H, Halldórsson BV, Stefánsson K. A sequence variant associating with educational attainment also affects childhood cognition. Sci Rep 2016; 6:36189. [PMID: 27811963 PMCID: PMC5095652 DOI: 10.1038/srep36189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/12/2016] [Indexed: 11/21/2022] Open
Abstract
Only a few common variants in the sequence of the genome have been shown to impact cognitive traits. Here we demonstrate that polygenic scores of educational attainment predict specific aspects of childhood cognition, as measured with IQ. Recently, three sequence variants were shown to associate with educational attainment, a confluence phenotype of genetic and environmental factors contributing to academic success. We show that one of these variants associating with educational attainment, rs4851266-T, also associates with Verbal IQ in dyslexic children (P = 4.3 × 10−4, β = 0.16 s.d.). The effect of 0.16 s.d. corresponds to 1.4 IQ points for heterozygotes and 2.8 IQ points for homozygotes. We verified this association in independent samples consisting of adults (P = 8.3 × 10−5, β = 0.12 s.d., combined P = 2.2 x 10−7, β = 0.14 s.d.). Childhood cognition is unlikely to be affected by education attained later in life, and the variant explains a greater fraction of the variance in verbal IQ than in educational attainment (0.7% vs 0.12%,. P = 1.0 × 10−5).
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Affiliation(s)
| | | | | | - Bettina Konte
- Department of Psychiatry, Psychotherapy and Psychosomatics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | | | | | - Birte Kehr
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland
| | | | - Hannes Helgason
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | - Paul D Iordache
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,Institute of Biomedical and Neural Engineering, Reykjavík University, Reykjavík, Iceland
| | | | | | | | | | | | - Ina Giegling
- Department of Psychiatry, Psychotherapy and Psychosomatics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Srdjan Djurovic
- NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Medical Genetics, Oslo University Hospital, Oslo 0450, Norway
| | - Kjetil S Sundet
- Department of Psychology, University of Oslo, Oslo 0373, Norway.,NORMENT - KG Jebsen Centre, Institute of Clinical Medicine, University of Oslo, Oslo N-0316, Norway
| | - Thomas Espeseth
- Department of Psychology, University of Oslo, Oslo 0373, Norway.,NORMENT - KG Jebsen Centre, Institute of Clinical Medicine, University of Oslo, Oslo N-0316, Norway
| | - Ingrid Melle
- Department of Medical Genetics, Oslo University Hospital, Oslo 0450, Norway.,Department of Psychology, University of Oslo, Oslo 0373, Norway
| | - Annette M Hartmann
- Department of Psychiatry, Psychotherapy and Psychosomatics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Unnur Thorsteinsdottir
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | | | - Daníel F Guðbjartsson
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Ole A Andreassen
- NORMENT - KG Jebsen Centre, Institute of Clinical Medicine, University of Oslo, Oslo N-0316, Norway.,NORMENT - KG Jebsen Centre, Division of Mental Health and Addiction, Oslo University Hospital, Oslo 0424, Norway
| | - Dan Rujescu
- Department of Psychiatry, Psychotherapy and Psychosomatics, Martin-Luther-University Halle-Wittenberg, Halle, Germany.,Department of Psychiatry, University of Munich (LMU), Munich, Germany
| | | | | | - Bjarni V Halldórsson
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,Institute of Biomedical and Neural Engineering, Reykjavík University, Reykjavík, Iceland
| | - Kári Stefánsson
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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19
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Gabel LA, Manglani M, Escalona N, Cysner J, Hamilton R, Pfaffmann J, Johnson E. Translating dyslexia across species. ANNALS OF DYSLEXIA 2016; 66:319-336. [PMID: 27013331 DOI: 10.1007/s11881-016-0125-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/01/2016] [Indexed: 06/05/2023]
Abstract
Direct relationships between induced mutation in the DCDC2 candidate dyslexia susceptibility gene in mice and changes in behavioral measures of visual spatial learning have been reported. We were interested in determining whether performance on a visual-spatial learning and memory task could be translated across species (study 1) and whether children with reading impairment showed a similar impairment to animal models of the disorder (study 2). Study 1 included 37 participants who completed six trials of four different virtual Hebb-Williams maze configurations. A 2 × 4 × 6 mixed factorial repeated measures ANOVA indicated consistency in performance between humans and mice on these tasks, enabling us to translate across species. Study 2 included a total of 91 participants (age range = 8-13 years). Eighteen participants were identified with reading disorder by performance on the Woodcock-Johnson III Tests of Achievement. Participants completed six trials of five separate virtual Hebb-Williams maze configurations. A 2 × 5 × 6 mixed factorial ANCOVA (gender as covariate) indicated that individuals with reading impairment demonstrated impaired visuo-spatial performance on this task. Overall, results from this study suggest that we are able to translate behavioral deficits observed in genetic animal models of dyslexia to humans with reading impairment. Future studies will utilize the virtual environment to further explore the underlying basis for this impairment.
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Affiliation(s)
- Lisa A Gabel
- Department of Psychology, Lafayette College, Easton, PA, USA.
- Program in Neuroscience, Lafayette College, Easton, PA, USA.
| | | | | | - Jessica Cysner
- Program in Neuroscience, Lafayette College, Easton, PA, USA
| | | | | | - Evelyn Johnson
- Department of Special Education, Boise State University, Boise, ID, USA
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20
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Shao S, Niu Y, Zhang X, Kong R, Wang J, Liu L, Luo X, Zhang J, Song R. Opposite Associations between Individual KIAA0319 Polymorphisms and Developmental Dyslexia Risk across Populations: A Stratified Meta-Analysis by the Study Population. Sci Rep 2016; 6:30454. [PMID: 27464509 PMCID: PMC4964335 DOI: 10.1038/srep30454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 07/06/2016] [Indexed: 02/08/2023] Open
Abstract
KIAA0319 at the DYX2 locus is one of the most extensively studied candidate genes for developmental dyslexia (DD) owing to its important role in neuronal migration. Previous research on associations between KIAA0319 genetic variations and DD has yielded inconsistent results. It is important to establish a more precise estimate of the DD risk associated with these genetic variations. We carried out a meta-analysis of association studies involving KIAA0319 polymorphisms and DD risk. The results of pooled analysis indicated that none of the six investigated markers in or near the KIAA0319 gene are associated with DD. However, a stratified analysis by the study population revealed opposite associations involving KIAA0319 rs4504469 in European and Asian subgroups. The stratified analysis also showed that the KIAA0319 rs9461045 minor allele (T allele) has a protective effect in Asians. This meta-analysis has allowed us to establish the effects of specific KIAA0319 polymorphisms on DD risk with greater precision, as they vary across populations; analyzing one single nucleotide polymorphism at a time could not fully explain the genetic association for DD.
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Affiliation(s)
- Shanshan Shao
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yanfeng Niu
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xiaohui Zhang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Rui Kong
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia Wang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lingfei Liu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiu Luo
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jiajia Zhang
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, 29208, USA
| | - Ranran Song
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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21
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Gray Matter Features of Reading Disability: A Combined Meta-Analytic and Direct Analysis Approach(1,2,3,4). eNeuro 2016; 3:eN-CFN-0103-15. [PMID: 26835509 PMCID: PMC4724065 DOI: 10.1523/eneuro.0103-15.2015] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/21/2015] [Accepted: 12/25/2015] [Indexed: 01/18/2023] Open
Abstract
Meta-analysis of voxel-based morphometry dyslexia studies and direct analysis of 293 reading disability and control cases from six different research sites were performed to characterize defining gray matter features of reading disability. These analyses demonstrated consistently lower gray matter volume in left posterior superior temporal sulcus/middle temporal gyrus regions and left orbitofrontal gyrus/pars orbitalis regions. Gray matter volume within both of these regions significantly predicted individual variation in reading comprehension after correcting for multiple comparisons. These regional gray matter differences were observed across published studies and in the multisite dataset after controlling for potential age and gender effects, and despite increased anatomical variance in the reading disability group, but were not significant after controlling for total gray matter volume. Thus, the orbitofrontal and posterior superior temporal sulcus gray matter findings are relatively reliable effects that appear to be dependent on cases with low total gray matter volume. The results are considered in the context of genetics studies linking orbitofrontal and superior temporal sulcus regions to alleles that confer risk for reading disability.
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Jacobson LA, Koriakin T, Lipkin P, Boada R, Frijters JC, Lovett MW, Hill D, Willcutt E, Gottwald S, Wolf M, Bosson-Heenan J, Gruen JR, Mahone EM. Executive Functions Contribute Uniquely to Reading Competence in Minority Youth. JOURNAL OF LEARNING DISABILITIES 2016; 50:422-433. [PMID: 26755569 PMCID: PMC5960349 DOI: 10.1177/0022219415618501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Competent reading requires various skills beyond those for basic word reading (i.e., core language skills, rapid naming, phonological processing). Contributing "higher-level" or domain-general processes include information processing speed and executive functions (working memory, strategic problem solving, attentional switching). Research in this area has relied on largely Caucasian samples, with limited representation of children from racial or ethnic minority groups. This study examined contributions of executive skills to reading competence in 761 children of minority backgrounds. Hierarchical linear regressions examined unique contributions of executive functions (EF) to word reading, fluency, and comprehension. EF contributed uniquely to reading performance, over and above reading-related language skills; working memory contributed uniquely to all components of reading; while attentional switching, but not problem solving, contributed to isolated and contextual word reading and reading fluency. Problem solving uniquely predicted comprehension, suggesting that this skill may be especially important for reading comprehension in minority youth. Attentional switching may play a unique role in development of reading fluency in minority youth, perhaps as a result of the increased demand for switching between spoken versus written dialects. Findings have implications for educational and clinical practice with regard to reading instruction, remedial reading intervention, and assessment of individuals with reading difficulty.
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Affiliation(s)
- Lisa A Jacobson
- 1 Kennedy Krieger Institute, Baltimore, MD, USA
- 2 Johns Hopkins University School of Medicine, Baltimore, MD, USA
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | - Taylor Koriakin
- 1 Kennedy Krieger Institute, Baltimore, MD, USA
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | - Paul Lipkin
- 1 Kennedy Krieger Institute, Baltimore, MD, USA
- 2 Johns Hopkins University School of Medicine, Baltimore, MD, USA
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | - Richard Boada
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | | | | | - Dina Hill
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | - Erik Willcutt
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | | | - Maryanne Wolf
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
| | | | - Jeffrey R Gruen
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
- 4 Yale University, New Haven, CT, USA
| | - E Mark Mahone
- 1 Kennedy Krieger Institute, Baltimore, MD, USA
- 2 Johns Hopkins University School of Medicine, Baltimore, MD, USA
- 3 Genes, Reading and Dyslexia Study, New Haven, CT, USA
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23
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Powers NR, Eicher JD, Miller LL, Kong Y, Smith SD, Pennington BF, Willcutt EG, Olson RK, Ring SM, Gruen JR. The regulatory element READ1 epistatically influences reading and language, with both deleterious and protective alleles. J Med Genet 2015; 53:163-71. [PMID: 26660103 PMCID: PMC4789805 DOI: 10.1136/jmedgenet-2015-103418] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/14/2015] [Indexed: 01/05/2023]
Abstract
Background Reading disability (RD) and language impairment (LI) are heritable learning disabilities that obstruct acquisition and use of written and spoken language, respectively. We previously reported that two risk haplotypes, each in strong linkage disequilibrium (LD) with an allele of READ1, a polymorphic compound short tandem repeat within intron 2 of risk gene DCDC2, are associated with RD and LI. Additionally, we showed a non-additive genetic interaction between READ1 and KIAHap, a previously reported risk haplotype in risk gene KIAA0319, and that READ1 binds the transcriptional regulator ETV6. Objective To examine the hypothesis that READ1 is a transcriptional regulator of KIAA0319. Methods We characterised associations between READ1 alleles and RD and LI in a large European cohort, and also assessed interactions between READ1 and KIAHap and their effect on performance on measures of reading, language and IQ. We also used family-based data to characterise the genetic interaction, and chromatin conformation capture (3C) to investigate the possibility of a physical interaction between READ1 and KIAHap. Results and conclusions READ1 and KIAHap show interdependence—READ1 risk alleles synergise with KIAHap, whereas READ1 protective alleles act epistatically to negate the effects of KIAHap. The family data suggest that these variants interact in trans genetically, while the 3C results show that a region of DCDC2 containing READ1 interacts physically with the region upstream of KIAA0319. These data support a model in which READ1 regulates KIAA0319 expression through KIAHap and in which the additive effects of READ1 and KIAHap alleles are responsible for the trans genetic interaction.
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Affiliation(s)
- Natalie R Powers
- Investigate Medicine, Yale University, New Haven, Connecticut, USA Department of Pediatrics, Yale University, New Haven, Connecticut, USA
| | - John D Eicher
- Investigate Medicine, Yale University, New Haven, Connecticut, USA
| | - Laura L Miller
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Yong Kong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University, New Haven, Connecticut, USA
| | - Shelley D Smith
- Departments of Pediatrics and Developmental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | | | - Erik G Willcutt
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, USA Departments of Psychology and Neuroscience, University of Colorado, Boulder, Colorado, USA
| | - Richard K Olson
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, USA Departments of Psychology and Neuroscience, University of Colorado, Boulder, Colorado, USA
| | - Susan M Ring
- School of Social and Community Medicine, University of Bristol, Bristol, UK MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Jeffrey R Gruen
- Investigate Medicine, Yale University, New Haven, Connecticut, USA Department of Pediatrics, Yale University, New Haven, Connecticut, USA Department of Investigative Medicine, Yale University, New Haven, Connecticut, USA
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24
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Eicher JD, Stein CM, Deng F, Ciesla AA, Powers NR, Boada R, Smith SD, Pennington BF, Iyengar SK, Lewis BA, Gruen JR. The DYX2 locus and neurochemical signaling genes contribute to speech sound disorder and related neurocognitive domains. GENES BRAIN AND BEHAVIOR 2015; 14:377-85. [PMID: 25778907 PMCID: PMC4492462 DOI: 10.1111/gbb.12214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 03/05/2015] [Accepted: 03/12/2015] [Indexed: 12/17/2022]
Abstract
A major milestone of child development is the acquisition and use of speech and language. Communication disorders, including speech sound disorder (SSD), can impair a child's academic, social and behavioral development. Speech sound disorder is a complex, polygenic trait with a substantial genetic component. However, specific genes that contribute to SSD remain largely unknown. To identify associated genes, we assessed the association of the DYX2 dyslexia risk locus and markers in neurochemical signaling genes (e.g., nicotinic and dopaminergic) with SSD and related endophenotypes. We first performed separate primary associations in two independent samples - Cleveland SSD (210 affected and 257 unaffected individuals in 127 families) and Denver SSD (113 affected individuals and 106 unaffected individuals in 85 families) - and then combined results by meta-analysis. DYX2 markers, specifically those in the 3' untranslated region of DCDC2 (P = 1.43 × 10(-4) ), showed the strongest associations with phonological awareness. We also observed suggestive associations of dopaminergic-related genes ANKK1 (P = 1.02 × 10(-2) ) and DRD2 (P = 9.22 × 10(-3) ) and nicotinic-related genes CHRNA3 (P = 2.51 × 10(-3) ) and BDNF (P = 8.14 × 10(-3) ) with case-control status and articulation. Our results further implicate variation in putative regulatory regions in the DYX2 locus, particularly in DCDC2, influencing language and cognitive traits. The results also support previous studies implicating variation in dopaminergic and nicotinic neural signaling influencing human communication and cognitive development. Our findings expand the literature showing genetic factors (e.g., DYX2) contributing to multiple related, yet distinct neurocognitive domains (e.g., dyslexia, language impairment, and SSD). How these factors interactively yield different neurocognitive and language-related outcomes remains to be elucidated.
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Affiliation(s)
- J D Eicher
- Department of Genetics, Yale University School of Medicine, New Haven, CT
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25
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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: 32] [Impact Index Per Article: 3.2] [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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26
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Grati M, Chakchouk I, Ma Q, Bensaid M, Desmidt A, Turki N, Yan D, Baanannou A, Mittal R, Driss N, Blanton S, Farooq A, Lu Z, Liu XZ, Masmoudi S. A missense mutation in DCDC2 causes human recessive deafness DFNB66, likely by interfering with sensory hair cell and supporting cell cilia length regulation. Hum Mol Genet 2015; 24:2482-91. [PMID: 25601850 DOI: 10.1093/hmg/ddv009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/13/2015] [Indexed: 11/12/2022] Open
Abstract
Hearing loss is the most common sensory deficit in humans. We show that a point mutation in DCDC2 (DCDC2a), a member of doublecortin domain-containing protein superfamily, causes non-syndromic recessive deafness DFNB66 in a Tunisian family. Using immunofluorescence on rat inner ear neuroepithelia, DCDC2a was found to localize to the kinocilia of sensory hair cells and the primary cilia of nonsensory supporting cells. DCDC2a fluorescence is distributed along the length of the kinocilium with increased density toward the tip. DCDC2a-GFP overexpression in non-polarized COS7 cells induces the formation of long microtubule-based cytosolic cables suggesting a role in microtubule formation and stabilization. Deafness mutant DCDC2a expression in hair cells and supporting cells causes cilium structural defects, such as cilium branching, and up to a 3-fold increase in length ratios. In zebrafish, the ortholog dcdc2b was found to be essential for hair cell development, survival and function. Our results reveal DCDC2a to be a deafness gene and a player in hair cell kinocilia and supporting cell primary cilia length regulation likely via its role in microtubule formation and stabilization.
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Affiliation(s)
- M'hamed Grati
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Imen Chakchouk
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisie
| | - Qi Ma
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Mariem Bensaid
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisie
| | | | - Nouha Turki
- Service Otorhinolaryngologie, Hôpital Universitaire Mahdia, Mahdia, Tunisie
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Aissette Baanannou
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisie
| | - Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Nabil Driss
- Service Otorhinolaryngologie, Hôpital Universitaire Mahdia, Mahdia, Tunisie
| | - Susan Blanton
- Dr John T. Macdonald Foundation Department of Human Genetics, and John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL 33146, USA and
| | - Amjad Farooq
- Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Zhongmin Lu
- Department of Biology, University of Miami, Miami, FL 33146, USA
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA,
| | - Saber Masmoudi
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisie,
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