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Thomas T, Khalaf S, Grigorenko EL. A systematic review and meta-analysis of imaging genetics studies of specific reading disorder. Cogn Neuropsychol 2021; 38:179-204. [PMID: 34529546 DOI: 10.1080/02643294.2021.1969900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The imaging genetics of specific reading disabilities (SRD) is an emerging field that aims to characterize the disabilities' neurobiological causes, including atypical brain structure and function and distinct genetic architecture. The present review aimed to summarize current imaging genetics studies of SRD, characterize the effect sizes of reported results by calculating Cohen's d, complete a Fisher's Combined Probability Test for genes featured in multiple studies, and determine areas for future research. Results demonstrate associations between SRD risk genes and reading network brain phenotypes. The Fisher's test revealed promising results for the genes DCDC2, KIAA0319, FOXP2, SLC2A3, and ROBO1. Future research should focus on exploratory approaches to identify previously undiscovered genes. Using comprehensive neuroimaging (e.g., functional and effective connectivity) and genetic (e.g., sequencing and epigenetic) techniques, and using larger samples, diverse stages of development, and longitudinal investigations, would help researchers understand the neurobiological correlates of SRD to improve early identification.
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Affiliation(s)
- Tina Thomas
- Department of Psychology, University of Houston, Houston, TX, USA.,Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
| | - Shiva Khalaf
- Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
| | - Elena L Grigorenko
- Department of Psychology, University of Houston, Houston, TX, USA.,Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA.,Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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2
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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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3
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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: 9] [Impact Index Per Article: 3.0] [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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Heidlmayr K, Ferragne E, Isel F. Neuroplasticity in the phonological system: The PMN and the N400 as markers for the perception of non-native phonemic contrasts by late second language learners. Neuropsychologia 2021; 156:107831. [PMID: 33753084 DOI: 10.1016/j.neuropsychologia.2021.107831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 12/28/2020] [Accepted: 03/17/2021] [Indexed: 02/04/2023]
Abstract
Second language (L2) learners frequently encounter persistent difficulty in perceiving certain non-native sound contrasts, i.e., a phenomenon called "phonological deafness". However, if extensive L2 experience leads to neuroplastic changes in the phonological system, then the capacity to discriminate non-native phonemic contrasts should progressively improve. Such perceptual changes should be attested by modifications at the neurophysiological level. We designed an EEG experiment in which the listeners' perceptual capacities to discriminate second language phonemic contrasts influence the processing of lexical-semantic violations. Semantic congruency of critical words in a sentence context was driven by a phonemic contrast that was unique to the L2, English (e.g.,/ɪ/-/i:/, ship - sheep). Twenty-eight young adult native speakers of French with intermediate proficiency in English listened to sentences that contained either a semantically congruent or incongruent critical word (e.g., The anchor of theship/*sheepwas let down) while EEG was recorded. Three ERP effects were found to relate to increasing L2 proficiency: (1) a left frontal auditory N100 effect, (2) a smaller fronto-central phonological mismatch negativity (PMN) effect and (3) a semantic N400 effect. No effect of proficiency was found on oscillatory markers. The current findings suggest that neuronal plasticity in the human brain allows for the late acquisition of even hard-wired linguistic features such as the discrimination of phonemic contrasts in a second language. This is the first time that behavioral and neurophysiological evidence for the critical role of neural plasticity underlying L2 phonological processing and its interdependence with semantic processing has been provided. Our data strongly support the idea that pieces of information from different levels of linguistic processing (e.g., phonological, semantic) strongly interact and influence each other during online language processing.
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Affiliation(s)
- Karin Heidlmayr
- UMR 1253, iBrain, University of Tours, Inserm, Tours, France; Max-Planck Institute for Psycholinguistics, Nijmegen, the Netherlands; Laboratory CLILLAC-ARP - URP3967, Université de Paris, Paris, France; Laboratory Models, Dynamics, Corpus, CNRS/University Paris Nanterre, Paris Lumières, France.
| | - Emmanuel Ferragne
- Laboratory CLILLAC-ARP - URP3967, Université de Paris, Paris, France
| | - Frédéric Isel
- Laboratory Models, Dynamics, Corpus, CNRS/University Paris Nanterre, Paris Lumières, France
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Kershner JR. An Evolutionary Perspective of Dyslexia, Stress, and Brain Network Homeostasis. Front Hum Neurosci 2021; 14:575546. [PMID: 33551772 PMCID: PMC7859477 DOI: 10.3389/fnhum.2020.575546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/18/2020] [Indexed: 12/20/2022] Open
Abstract
Evolution fuels interindividual variability in neuroplasticity, reflected in brain anatomy and functional connectivity of the expanding neocortical regions subserving reading ability. Such variability is orchestrated by an evolutionarily conserved, competitive balance between epigenetic, stress-induced, and cognitive-growth gene expression programs. An evolutionary developmental model of dyslexia, suggests that prenatal and childhood subclinical stress becomes a risk factor for dyslexia when physiological adaptations to stress promoting adaptive fitness, may attenuate neuroplasticity in the brain regions recruited for reading. Stress has the potential to blunt the cognitive-growth functions of the predominantly right hemisphere Ventral and Dorsal attention networks, which are primed with high entropic levels of synaptic plasticity, and are critical for acquiring beginning reading skills. The attentional networks, in collaboration with the stress-responsive Default Mode network, modulate the entrainment and processing of the low frequency auditory oscillations (1-8 Hz) and visuospatial orienting linked etiologically to dyslexia. Thus, dyslexia may result from positive, but costly adaptations to stress system dysregulation: protective measures that reset the stress/growth balance of processing to favor the Default Mode network, compromising development of the attentional networks. Such a normal-variability conceptualization of dyslexia is at odds with the frequent assumption that dyslexia results from a neurological abnormality. To put the normal-variability model in the broader perspective of the state of the field, a traditional evolutionary account of dyslexia is presented to stimulate discussion of the scientific merits of the two approaches.
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Affiliation(s)
- John R. Kershner
- Department of Applied Psychology, University of Toronto, Toronto, ON, Canada
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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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7
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Sánchez-Morán M, Hernández JA, Duñabeitia JA, Estévez A, Bárcena L, González-Lahera A, Bajo MT, Fuentes LJ, Aransay AM, Carreiras M. Genetic association study of dyslexia and ADHD candidate genes in a Spanish cohort: Implications of comorbid samples. PLoS One 2018; 13:e0206431. [PMID: 30379906 PMCID: PMC6209299 DOI: 10.1371/journal.pone.0206431] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/13/2018] [Indexed: 01/21/2023] Open
Abstract
Dyslexia and attention deficit hyperactivity disorder (ADHD) are two complex neuro-behaviorally disorders that co-occur more often than expected, so that reading disability has been linked to inattention symptoms. We examined 4 SNPs located on genes previously associated to dyslexia (KIAA0319, DCDC2, DYX1C1 and FOXP2) and 3 SNPs within genes related to ADHD (COMT, MAOA and DBH) in a cohort of Spanish children (N = 2078) that met the criteria of having one, both or none of these disorders (dyslexia and ADHD). We used a case-control approach comparing different groups of samples based on each individual diagnosis. In addition, we also performed a quantitative trait analysis with psychometric measures on the general population (N = 3357). The results indicated that the significance values for some markers change depending on the phenotypic groups compared and/or when considering pair-wise marker interactions. Furthermore, our quantitative trait study showed significant genetic associations with specific cognitive processes. These outcomes advocate the importance of establishing rigorous and homogeneous criteria for the diagnosis of cognitive disorders, as well as the relevance of considering cognitive endophenotypes.
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Affiliation(s)
- Mirian Sánchez-Morán
- BCBL-Basque Center on Cognition Brain and Language, Donostia-San Sebastian, Gipuzkoa, Spain
- CIC bioGUNE, Derio, Bizkaia, Spain
| | | | - Jon Andoni Duñabeitia
- BCBL-Basque Center on Cognition Brain and Language, Donostia-San Sebastian, Gipuzkoa, Spain
| | | | | | | | - María Teresa Bajo
- Research Center for Brain, Mind & Behavior, Universidad de Granada, Granada, Spain
| | | | - Ana M. Aransay
- CIC bioGUNE, Derio, Bizkaia, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Manuel Carreiras
- BCBL-Basque Center on Cognition Brain and Language, Donostia-San Sebastian, Gipuzkoa, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Universidad del Pais Vasco UPV/EHU, Leioa, Bizkaia, Spain
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8
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Murphy E, Benítez-Burraco A. Toward the Language Oscillogenome. Front Psychol 2018; 9:1999. [PMID: 30405489 PMCID: PMC6206218 DOI: 10.3389/fpsyg.2018.01999] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/28/2018] [Indexed: 12/20/2022] Open
Abstract
Language has been argued to arise, both ontogenetically and phylogenetically, from specific patterns of brain wiring. We argue that it can further be shown that core features of language processing emerge from particular phasal and cross-frequency coupling properties of neural oscillations; what has been referred to as the language ‘oscillome.’ It is expected that basic aspects of the language oscillome result from genetic guidance, what we will here call the language ‘oscillogenome,’ for which we will put forward a list of candidate genes. We have considered genes for altered brain rhythmicity in conditions involving language deficits: autism spectrum disorders, schizophrenia, specific language impairment and dyslexia. These selected genes map on to aspects of brain function, particularly on to neurotransmitter function. We stress that caution should be adopted in the construction of any oscillogenome, given the range of potential roles particular localized frequency bands have in cognition. Our aim is to propose a set of genome-to-language linking hypotheses that, given testing, would grant explanatory power to brain rhythms with respect to language processing and evolution.
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Affiliation(s)
- Elliot Murphy
- Division of Psychology and Language Sciences, University College London, London, United Kingdom.,Department of Psychology, University of Westminster, London, United Kingdom
| | - Antonio Benítez-Burraco
- Department of Spanish Language, Linguistics and Literary Theory, University of Seville, Seville, Spain
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Worldwide distribution of the DCDC2 READ1 regulatory element and its relationship with phoneme variation across languages. Proc Natl Acad Sci U S A 2018; 115:4951-4956. [PMID: 29666269 PMCID: PMC5948951 DOI: 10.1073/pnas.1710472115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Languages evolve rapidly due to an interaction between sociocultural factors and underlying phonological processes that are influenced by genetic factors. DCDC2 has been strongly associated with core components of the phonological processing system in animal models and multiple independent studies of populations and languages. To characterize subtle language differences arising from genetic variants associated with phonological processes, we examined the relationship between READ1, a regulatory element in DCDC2, and phonemes in languages of 43 populations across five continents. Variation in READ1 was significantly correlated with the number of consonants. Our results suggest that subtle cognitive biases conferred by different READ1 alleles are amplified through cultural transmission that shape consonant use by populations over time. DCDC2 is a gene strongly associated with components of the phonological processing system in animal models and in multiple independent studies of populations and languages. We propose that it may also influence population-level variation in language component usage. To test this hypothesis, we investigated the evolution and worldwide distribution of the READ1 regulatory element within DCDC2, and compared its distribution with variation in different language properties. The mutational history of READ1 was estimated by examining primate and archaic hominin sequences. This identified duplication and expansion events, which created a large number of polymorphic alleles based on internal repeat units (RU1 and RU2). Association of READ1 alleles was studied with respect to the numbers of consonants and vowels for languages in 43 human populations distributed across five continents. Using population-based approaches with multivariate ANCOVA and linear mixed effects analyses, we found that the RU1-1 allele group of READ1 is significantly associated with the number of consonants within languages independent of genetic relatedness, geographic proximity, and language family. We propose that allelic variation in READ1 helped create a subtle cognitive bias that was amplified by cultural transmission, and ultimately shaped consonant use by different populations over time.
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10
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Schmitz J, Kumsta R, Moser D, Güntürkün O, Ocklenburg S. KIAA0319 promoter DNA methylation predicts dichotic listening performance in forced-attention conditions. Behav Brain Res 2018; 337:1-7. [DOI: 10.1016/j.bbr.2017.09.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/19/2017] [Accepted: 09/22/2017] [Indexed: 12/21/2022]
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11
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Cortical responses to tone and phoneme mismatch as a predictor of dyslexia? A systematic review. Schizophr Res 2018; 191:148-160. [PMID: 28712970 DOI: 10.1016/j.schres.2017.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/30/2017] [Accepted: 07/04/2017] [Indexed: 11/22/2022]
Abstract
Evidence from event-related-potential (ERP) studies has repeatedly shown differences in the perception and processing of auditory stimuli in children with dyslexia compared to control children. The mismatch negativity (MMN) - an ERP component reflecting passive auditory change detection ability - has been found to be reduced, not only in children with a diagnosis of dyslexia, but also in infants and preschool children at risk of developing dyslexia. However, the results are controversial due to the different methods, age of the children and stimuli used. The aim of the present review is to summarize and evaluate the MMN research about at-risk children in order to identify risk factors that discriminate between children with and without dyslexia risk and to analyze if the MMR (the abbreviation refers to positive and negative mismatch responses) correlates with later reading and spelling ability. A literature search yielded 17 studies reporting MMR to speech or non-speech stimuli in children at risk of dyslexia. The results of the studies were inconsistent. Studies measuring speech MMR often found attenuated amplitudes in the at-risk group, but mainly in very young children. The results for older children (6-7years) and for non-speech stimuli are more heterogeneous. A moderate positive correlation of MMR amplitude size with later reading and spelling abilities was consistently found. Overall, the findings of this review indicate that the MMR can be a valuable part of early dyslexia identification, which can enable efficient support and intervention for a child before the first problems appear.
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12
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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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13
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Adams AK, Smith SD, Truong DT, Willcutt EG, Olson RK, DeFries JC, Pennington BF, Gruen JR. Enrichment of putatively damaging rare variants in the DYX2 locus and the reading-related genes CCDC136 and FLNC. Hum Genet 2017; 136:1395-1405. [PMID: 28866788 PMCID: PMC5702371 DOI: 10.1007/s00439-017-1838-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/24/2017] [Indexed: 12/19/2022]
Abstract
Eleven loci with prior evidence for association with reading and language phenotypes were sequenced in 96 unrelated subjects with significant impairment in reading performance drawn from the Colorado Learning Disability Research Center collection. Out of 148 total individual missense variants identified, the chromosome 7 genes CCDC136 and FLNC contained 19. In addition, a region corresponding to the well-known DYX2 locus for RD contained 74 missense variants. Both allele sets were filtered for a minor allele frequency ≤0.01 and high Polyphen-2 scores. To determine if observations of these alleles are occurring more frequently in our cases than expected by chance in aggregate, counts from our sample were compared to the number of observations in the European subset of the 1000 Genomes Project using Fisher's exact test. Significant P values were achieved for both CCDC136/FLNC (P = 0.0098) and the DYX2 locus (P = 0.012). Taken together, this evidence further supports the influence of these regions on reading performance. These results also support the influence of rare variants in reading disability.
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Affiliation(s)
- Andrew K Adams
- Department of Genetics, Yale University, New Haven, CT, USA
| | - Shelley D Smith
- Munroe Meyer Institute, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Erik G Willcutt
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, USA
| | - Richard K Olson
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, USA
| | - John C DeFries
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, USA
| | | | - Jeffrey R Gruen
- Department of Genetics, Yale University, New Haven, CT, USA.
- Department of Pediatrics and the Investigative Medicine Program, Yale University, New Haven, CT, USA.
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14
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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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15
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Hancock R, Pugh KR, Hoeft F. Neural Noise Hypothesis of Developmental Dyslexia. Trends Cogn Sci 2017; 21:434-448. [PMID: 28400089 PMCID: PMC5489551 DOI: 10.1016/j.tics.2017.03.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/27/2017] [Accepted: 03/15/2017] [Indexed: 11/26/2022]
Abstract
Developmental dyslexia (decoding-based reading disorder; RD) is a complex trait with multifactorial origins at the genetic, neural, and cognitive levels. There is evidence that low-level sensory-processing deficits precede and underlie phonological problems, which are one of the best-documented aspects of RD. RD is also associated with impairments in integrating visual symbols with their corresponding speech sounds. Although causal relationships between sensory processing, print-speech integration, and fluent reading, and their neural bases are debated, these processes all require precise timing mechanisms across distributed brain networks. Neural excitability and neural noise are fundamental to these timing mechanisms. Here, we propose that neural noise stemming from increased neural excitability in cortical networks implicated in reading is one key distal contributor to RD.
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Affiliation(s)
- Roeland Hancock
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco (UCSF), 401 Parnassus Ave. Box-0984, San Francisco, CA 94143, USA; Science-based Innovation in Learning Center (SILC), 401 Parnassus Ave. Box-0984, San Francisco, CA 94143, USA.
| | - Kenneth R Pugh
- Haskins Laboratories, 300 George Street, New Haven, CT 06511, USA; Department of Linguistics, Yale University, 370 Temple Street, New Haven, CT 06520, USA; Department of Radiology and Biomedical Imaging, Yale University, 330 Cedar Street, New Haven, CT 06520, USA; Department of Psychological Sciences, University of Connecticut, 406 Babbidge Road, Storrs, CT 06269, USA
| | - Fumiko Hoeft
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco (UCSF), 401 Parnassus Ave. Box-0984, San Francisco, CA 94143, USA; Haskins Laboratories, 300 George Street, New Haven, CT 06511, USA; Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160, Japan; Science-based Innovation in Learning Center (SILC), 401 Parnassus Ave. Box-0984, San Francisco, CA 94143, USA; Dyslexia Center, UCSF, 675 Nelson Rising Lane, San Francisco, CA 94158, USA.
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16
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An oscillopathic approach to developmental dyslexia: From genes to speech processing. Behav Brain Res 2017; 329:84-95. [DOI: 10.1016/j.bbr.2017.03.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/14/2017] [Accepted: 03/18/2017] [Indexed: 12/27/2022]
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17
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Neef NE, Müller B, Liebig J, Schaadt G, Grigutsch M, Gunter TC, Wilcke A, Kirsten H, Skeide MA, Kraft I, Kraus N, Emmrich F, Brauer J, Boltze J, Friederici AD. Dyslexia risk gene relates to representation of sound in the auditory brainstem. Dev Cogn Neurosci 2017; 24:63-71. [PMID: 28182973 PMCID: PMC6987796 DOI: 10.1016/j.dcn.2017.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/15/2017] [Accepted: 01/15/2017] [Indexed: 12/20/2022] Open
Abstract
Previous studies associate poor reading with unstable speech-evoked brainstem responses. DCDC2 and KIAA0319 risk alleles form a strong genetic link with developmental dyslexia. Genetic burden with KIAA0319 risk is related to unstable speech-evoked brainstem responses. Genetic burden with DCDC2 risk is related to intact speech-evoked brainstem responses. Revealed brain-gene relationships may inform the multifactorial pathophysiology of dyslexia.
Dyslexia is a reading disorder with strong associations with KIAA0319 and DCDC2. Both genes play a functional role in spike time precision of neurons. Strikingly, poor readers show an imprecise encoding of fast transients of speech in the auditory brainstem. Whether dyslexia risk genes are related to the quality of sound encoding in the auditory brainstem remains to be investigated. Here, we quantified the response consistency of speech-evoked brainstem responses to the acoustically presented syllable [da] in 159 genotyped, literate and preliterate children. When controlling for age, sex, familial risk and intelligence, partial correlation analyses associated a higher dyslexia risk loading with KIAA0319 with noisier responses. In contrast, a higher risk loading with DCDC2 was associated with a trend towards more stable responses. These results suggest that unstable representation of sound, and thus, reduced neural discrimination ability of stop consonants, occurred in genotypes carrying a higher amount of KIAA0319 risk alleles. Current data provide the first evidence that the dyslexia-associated gene KIAA0319 can alter brainstem responses and impair phoneme processing in the auditory brainstem. This brain-gene relationship provides insight into the complex relationships between phenotype and genotype thereby improving the understanding of the dyslexia-inherent complex multifactorial condition.
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Affiliation(s)
- Nicole E Neef
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany.
| | - Bent Müller
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Johanna Liebig
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Gesa Schaadt
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany; Department of Psychology, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Maren Grigutsch
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Thomas C Gunter
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Arndt Wilcke
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Holger Kirsten
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig and LIFE-Leipzig Research Center for Civilization Diseases, University of Leipzig, Germany
| | - Michael A Skeide
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Indra Kraft
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Nina Kraus
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL 60208, USA
| | - Frank Emmrich
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Jens Brauer
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Johannes Boltze
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; Department of Medical Cell Technology, Fraunhofer Research Institution for Marine Biotechnology, and Institute for Medical and Marine Biotechnology, University of Lübeck, Germany
| | - Angela D Friederici
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
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18
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Chen Y, Zhao H, Zhang YX, Zuo PX. DCDC2 gene polymorphisms are associated with developmental dyslexia in Chinese Uyghur children. Neural Regen Res 2017; 12:259-266. [PMID: 28400808 PMCID: PMC5361510 DOI: 10.4103/1673-5374.200809] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Developmental dyslexia is a complex reading and writing disorder with strong genetic components. In previous genetic studies about dyslexia, a number of candidate genes have been identified. These include DCDC2, which has repeatedly been associated with developmental dyslexia in various European and American populations. However, data regarding this relationship are varied according to population. The Uyghur people of China represent a Eurasian population with an interesting genetic profile. Thus, this group may provide useful information about the association between DCDC2 gene polymorphisms and dyslexia. In the current study, we examined genetic data from 392 Uyghur children aged 8–12 years old from the Xinjiang Uyghur Autonomous Region of China. Participants included 196 children with dyslexia and 196 grade-, age-, and gender-matched controls. DNA was isolated from oral mucosal cell samples and fourteen single nucleotide polymorphisms (rs6456593, rs1419228, rs34647318, rs9467075, rs793862, rs9295619, rs807701, rs807724, rs2274305, rs7765678, rs4599626, rs6922023, rs3765502, and rs1087266) in DCDC2 were screened via the SNPscan method. We compared SNP frequencies in five models (Codominant, Dominant, Recessive, Heterozygote advantage, and Allele) between the two groups by means of the chi-squared test. A single-locus analysis indicated that, with regard to the allele frequency of these polymorphisms, three SNPs (rs807724, rs2274305, and rs4599626) were associated with dyslexia. rs9467075 and rs2274305 displayed significant associations with developmental dyslexia under the dominant model. rs6456593 and rs6922023 were significantly associated with developmental dyslexia under the dominant model and in the heterozygous genotype. Additionally, we discovered that the T-G-C-T of the four-marker haplotype (rs9295619-rs807701-rs807724-rs2274305) and the T-A of the two-marker haplotype (rs3765502-1087266) were significantly different between cases and controls. Thus, we conclude that DCDC2 gene polymorphisms are associated with developmental dyslexia in Chinese Uyghur children.
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Affiliation(s)
- Yun Chen
- Medical College, Shihezi University, Shihezi, Xinjiang Uyghur Autonomous Region, China
| | - Hua Zhao
- Medical College, Shihezi University, Shihezi, Xinjiang Uyghur Autonomous Region, China
| | - Yi-Xin Zhang
- Special Clinic Department, the 12 Hospital of People's Liberation Army, Kashgar, Xinjiang Uyghur Autonomous Region, China
| | - Peng-Xiang Zuo
- Medical College, Shihezi University, Shihezi, Xinjiang Uyghur Autonomous Region, China
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19
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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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20
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Kuuluvainen S, Alku P, Makkonen T, Lipsanen J, Kujala T. Cortical speech and non-speech discrimination in relation to cognitive measures in preschool children. Eur J Neurosci 2016; 43:738-50. [DOI: 10.1111/ejn.13141] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Soila Kuuluvainen
- Cognitive Brain Research Unit; Institute of Behavioural Sciences; University of Helsinki; Helsinki Finland
| | - Paavo Alku
- Department of Signal Processing and Acoustics; Aalto University; Helsinki Finland
| | - Tommi Makkonen
- Cognitive Brain Research Unit; Institute of Behavioural Sciences; University of Helsinki; Helsinki Finland
| | - Jari Lipsanen
- Institute of Behavioural Sciences; University of Helsinki; Helsinki Finland
| | - Teija Kujala
- Cognitive Brain Research Unit; Institute of Behavioural Sciences; University of Helsinki; Helsinki Finland
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21
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Žarić G, Fraga González G, Tijms J, van der Molen MW, Blomert L, Bonte M. Crossmodal deficit in dyslexic children: practice affects the neural timing of letter-speech sound integration. Front Hum Neurosci 2015; 9:369. [PMID: 26157382 PMCID: PMC4478392 DOI: 10.3389/fnhum.2015.00369] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/11/2015] [Indexed: 11/16/2022] Open
Abstract
A failure to build solid letter-speech sound associations may contribute to reading impairments in developmental dyslexia. Whether this reduced neural integration of letters and speech sounds changes over time within individual children and how this relates to behavioral gains in reading skills remains unknown. In this research, we examined changes in event-related potential (ERP) measures of letter-speech sound integration over a 6-month period during which 9-year-old dyslexic readers (n = 17) followed a training in letter-speech sound coupling next to their regular reading curriculum. We presented the Dutch spoken vowels /a/ and /o/ as standard and deviant stimuli in one auditory and two audiovisual oddball conditions. In one audiovisual condition (AV0), the letter “a” was presented simultaneously with the vowels, while in the other (AV200) it was preceding vowel onset for 200 ms. Prior to the training (T1), dyslexic readers showed the expected pattern of typical auditory mismatch responses, together with the absence of letter-speech sound effects in a late negativity (LN) window. After the training (T2), our results showed earlier (and enhanced) crossmodal effects in the LN window. Most interestingly, earlier LN latency at T2 was significantly related to higher behavioral accuracy in letter-speech sound coupling. On a more general level, the timing of the earlier mismatch negativity (MMN) in the simultaneous condition (AV0) measured at T1, significantly related to reading fluency at both T1 and T2 as well as with reading gains. Our findings suggest that the reduced neural integration of letters and speech sounds in dyslexic children may show moderate improvement with reading instruction and training and that behavioral improvements relate especially to individual differences in the timing of this neural integration.
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Affiliation(s)
- Gojko Žarić
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center (M-BIC) Maastricht, Netherlands
| | - Gorka Fraga González
- Department of Developmental Psychology, University of Amsterdam Amsterdam, Netherlands ; Rudolf Berlin Center Amsterdam, Netherlands
| | - Jurgen Tijms
- Department of Developmental Psychology, University of Amsterdam Amsterdam, Netherlands ; IWAL Institute Amsterdam, Netherlands
| | - Maurits W van der Molen
- Department of Developmental Psychology, University of Amsterdam Amsterdam, Netherlands ; Amsterdam Brain and Cognition, University of Amsterdam Netherlands
| | - Leo Blomert
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center (M-BIC) Maastricht, Netherlands
| | - Milene Bonte
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center (M-BIC) Maastricht, Netherlands
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22
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Su M, Wang J, Maurer U, Zhang Y, Li J, McBride-Chang C, Tardif T, Liu Y, Shu H. Gene-environment interaction on neural mechanisms of orthographic processing in Chinese children. JOURNAL OF NEUROLINGUISTICS 2015; 33:172-186. [PMID: 26294811 PMCID: PMC4539967 DOI: 10.1016/j.jneuroling.2014.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The ability to process and identify visual words requires efficient orthographic processing of print, consisting of letters in alphabetic languages or characters in Chinese. The N170 is a robust neural marker for orthographic processes. Both genetic and environmental factors, such as home literacy, have been shown to influence orthographic processing at the behavioral level, but their relative contributions and interactions are not well understood. The present study aimed to reveal possible gene-by-environment interactions on orthographic processing at the behavioral and neural level in a normal children sample. Sixty 12 year old Chinese children from a 10-year longitudinal sample underwent an implicit visual-word color decision task on real words and stroke combinations. The ERP analysis focused on the increase of the occipito-temporal N170 to words compared to stroke combinations. The genetic analysis focused on two SNPs (rs1419228, rs1091047) in the gene DCDC2 based on previous findings linking these 2 SNPs to orthographic coding. Home literacy was measured previously as the number of children's books at home, when the children were at the age of 3. Relative to stroke combinations, real words evoked greater N170 in bilateral posterior brain regions. A significant interaction between rs1091047 and home literacy was observed on the changes of N170 comparing real words to stroke combinations in the left hemisphere. Particularly, children carrying the major allele "G" showed a similar N170 effect irrespective of their environment, while children carrying the minor allele "C" showed a smaller N170 effect in low home-literacy environment than those in good environment.
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Affiliation(s)
- Mengmeng Su
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
| | - Jiuju Wang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
- Peking University Sixth Hospital, Beijing, 100191, China
- Peking University Institute of Mental Health, Beijing, 100191, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Urs Maurer
- Department of Psychology, University of Zurich, Switzerland
| | - Yuping Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
- Department of Psychology, Chengdu Medical College, Chengdu, 610083, China
| | - Jun Li
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
| | | | - Twila Tardif
- Center for Human Growth and Development, University of Michigan, Ann Arbor, U.S.A
| | - Youyi Liu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
| | - Hua Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
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23
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Žarić G, Fraga González G, Tijms J, van der Molen MW, Blomert L, Bonte M. Reduced neural integration of letters and speech sounds in dyslexic children scales with individual differences in reading fluency. PLoS One 2014; 9:e110337. [PMID: 25329388 PMCID: PMC4199667 DOI: 10.1371/journal.pone.0110337] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 09/20/2014] [Indexed: 11/18/2022] Open
Abstract
The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter ‘a’ was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.
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Affiliation(s)
- Gojko Žarić
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, University of Maastricht, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
- * E-mail:
| | - Gorka Fraga González
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
- Rudolf Berlin Center, Amsterdam, Netherlands
| | - Jurgen Tijms
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
- IWAL Institute for Dyslexia, Amsterdam, Netherlands
- Rudolf Berlin Center, Amsterdam, Netherlands
| | - Maurits W. van der Molen
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
- Rudolf Berlin Center, Amsterdam, Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, Netherlands
| | - Leo Blomert
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, University of Maastricht, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
| | - Milene Bonte
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, University of Maastricht, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
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24
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Che A, Girgenti MJ, LoTurco J. The dyslexia-associated gene DCDC2 is required for spike-timing precision in mouse neocortex. Biol Psychiatry 2014; 76:387-96. [PMID: 24094509 PMCID: PMC4025976 DOI: 10.1016/j.biopsych.2013.08.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/06/2013] [Accepted: 08/22/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND Variants in dyslexia-associated genes, including DCDC2, have been linked to altered neocortical activation, suggesting that dyslexia associated genes might play as yet unspecified roles in neuronal physiology. METHODS Whole-cell patch clamp recordings were used to compare the electrophysiological properties of regular spiking pyramidal neurons of neocortex in Dcdc2 knockout (KO) and wild-type mice. Ribonucleic acid sequencing and reverse transcriptase polymerase chain reaction were performed to identify and characterize changes in gene expression in Dcdc2 KOs. RESULTS Neurons in KOs showed increased excitability and decreased temporal precision in action potential firing. The RNA sequencing screen revealed that the N-methyl-D-aspartate receptor (NMDAR) subunit Grin2B was elevated in Dcdc2 KOs, and an electrophysiological assessment confirmed a functional increase in spontaneous NMDAR-mediated activity. Remarkably, the decreased action potential temporal precision could be restored in mutants by treatment with either the NMDAR antagonist (2R)-amino-5-phosphonovaleric acid or the NMDAR 2B subunit-specific antagonist Ro 25-6981. CONCLUSIONS These results link the function of the dyslexia-associated gene Dcdc2 to spike timing through activity of NMDAR.
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Affiliation(s)
- Alicia Che
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Matthew J Girgenti
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Joseph LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut.
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25
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Centanni TM, Chen F, Booker AM, Engineer CT, Sloan AM, Rennaker RL, LoTurco JJ, Kilgard MP. Speech sound processing deficits and training-induced neural plasticity in rats with dyslexia gene knockdown. PLoS One 2014; 9:e98439. [PMID: 24871331 PMCID: PMC4037188 DOI: 10.1371/journal.pone.0098439] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 05/02/2014] [Indexed: 11/18/2022] Open
Abstract
In utero RNAi of the dyslexia-associated gene Kiaa0319 in rats (KIA-) degrades cortical responses to speech sounds and increases trial-by-trial variability in onset latency. We tested the hypothesis that KIA- rats would be impaired at speech sound discrimination. KIA- rats needed twice as much training in quiet conditions to perform at control levels and remained impaired at several speech tasks. Focused training using truncated speech sounds was able to normalize speech discrimination in quiet and background noise conditions. Training also normalized trial-by-trial neural variability and temporal phase locking. Cortical activity from speech trained KIA- rats was sufficient to accurately discriminate between similar consonant sounds. These results provide the first direct evidence that assumed reduced expression of the dyslexia-associated gene KIAA0319 can cause phoneme processing impairments similar to those seen in dyslexia and that intensive behavioral therapy can eliminate these impairments.
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Affiliation(s)
- Tracy M. Centanni
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Fuyi Chen
- Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Anne M. Booker
- Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Crystal T. Engineer
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Andrew M. Sloan
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Robert L. Rennaker
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Joseph J. LoTurco
- Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Michael P. Kilgard
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, United States of America
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Event-related potentials to tones show differences between children with multiple risk factors for dyslexia and control children before the onset of formal reading instruction. Int J Psychophysiol 2014; 95:101-12. [PMID: 24746550 DOI: 10.1016/j.ijpsycho.2014.04.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 03/26/2014] [Accepted: 04/07/2014] [Indexed: 11/23/2022]
Abstract
Multiple risk factors can affect the development of specific reading problems or dyslexia. In addition to the most prevalent and studied risk factor, phonological processing, auditory discrimination problems have also been found in children and adults with reading difficulties. The present study examined 37 children between the ages of 5 and 6, 11 of which had multiple risk factors for developing reading problems. The children participated in a passive oddball EEG experiment with sinusoidal sounds with changes in sound frequency, duration, or intensity. The responses to the standard stimuli showed a negative voltage shift in children at risk for reading problems compared to control children at 107-215 ms in frontocentral areas corresponding to P1 offset and N250 onset. Source analyses showed that the difference originated from the left and right auditory cortices. Additionally, the children at risk for reading problems had a larger late discriminative negativity (LDN) response in amplitude for sound frequency change than the control children. The amplitudes at the P1-N250 time window showed correlations to letter knowledge and phonological identification whereas the amplitudes at the LDN time window correlated with verbal short-term memory and rapid naming. These results support the view that problems in basic auditory processing abilities precede the onset of reading instruction and can act as one of the risk factors for dyslexia.
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27
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Condro MC, White SA. Recent Advances in the Genetics of Vocal Learning. COMPARATIVE COGNITION & BEHAVIOR REVIEWS 2014; 9:75-98. [PMID: 26052371 DOI: 10.3819/ccbr.2014.90003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Language is a complex communicative behavior unique to humans, and its genetic basis is poorly understood. Genes associated with human speech and language disorders provide some insights, originating with the FOXP2 transcription factor, a mutation in which is the source of an inherited form of developmental verbal dyspraxia. Subsequently, targets of FOXP2 regulation have been associated with speech and language disorders, along with other genes. Here, we review these recent findings that implicate genetic factors in human speech. Due to the exclusivity of language to humans, no single animal model is sufficient to study the complete behavioral effects of these genes. Fortunately, some animals possess subcomponents of language. One such subcomponent is vocal learning, which though rare in the animal kingdom, is shared with songbirds. We therefore discuss how songbird studies have contributed to the current understanding of genetic factors that impact human speech, and support the continued use of this animal model for such studies in the future.
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Affiliation(s)
- Michael C Condro
- Molecular, Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles
| | - Stephanie A White
- Department of Integrative Biology and Physiology, University of California, Los Angeles
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28
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FMRI of phonemic perception and its relationship to reading development in elementary- to middle-school-age children. Neuroimage 2013; 89:192-202. [PMID: 24315840 DOI: 10.1016/j.neuroimage.2013.11.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 11/10/2013] [Accepted: 11/23/2013] [Indexed: 11/21/2022] Open
Abstract
Neuroimaging studies suggest that categorical perception of speech phonemes in adults is primarily subserved by a pathway from bilateral primary auditory areas to association areas in the left middle superior temporal cortex, but the neural substrates underlying categorical speech perception in children are not yet known. Here, fMRI was used to examine the neural substrates associated with phoneme perception in 7- to 12-year-old children as well as the relationships among level of expertise in phoneme perception, the associated activation, and the development of reading and phonological processing abilities. While multiple regions in left frontal, temporal, and parietal cortex were found to be more responsive to phonemic than nonphonemic sounds, the extent of left lateralization in posterior temporal and parietal regions during phonemic relative to nonphonemic discrimination differed depending on the degree of categorical phoneme perception. In addition, an unexpected finding was that proficiency in categorical perception was strongly related to activation in the left ventral occipitotemporal cortex, an area frequently associated with orthographic processing. Furthermore, in children who showed lower proficiency in categorical perception, the level of categorical perception was positively correlated with reading ability and reading and reading-related abilities were inversely correlated with right mid-temporal activation in the phonemic relative to nonphonemic perception contrast. These results suggest that greater specialization of left hemisphere temporal and parietal regions for the categorical perception of phonemes, as well as activation of the region termed the visual word form area, may be important for the optimal developmental refinement of both phoneme perception and reading ability.
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29
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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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30
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Analysis of genetic variants of dyslexia candidate genes KIAA0319 and DCDC2 in Indian population. J Hum Genet 2013; 58:531-8. [PMID: 23677054 DOI: 10.1038/jhg.2013.46] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 11/08/2022]
Abstract
Developmental dyslexia (DD) is a heritable, complex genetic disorder associated with impairment in reading and writing skills despite having normal intellectual ability and appropriate educational opportunities. Chromosome 6p23-21.3 at DYX2 locus has showed the most consistent evidence of linkage for DD and two susceptible genes KIAA0319 and DCDC2 for DD at DYX2 locus showed significant association. Specific candidate gene-association studies have identified variants, risk haplotypes and microsatellites of KIAA0319 and DCDC2 correlated with wide range of reading-related traits. In this study, we used a case-control approach for analyzing single-nucleotide polymorphisms (SNPs) in KIAA0319 and DCDC2. Our study demonstrated the association of DD with SNP rs4504469 of KIAA0319 and not with any SNPs of DCDC2.
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31
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Neurogenetics and auditory processing in developmental dyslexia. Curr Opin Neurobiol 2013; 23:37-42. [PMID: 23040541 DOI: 10.1016/j.conb.2012.09.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 09/06/2012] [Accepted: 09/16/2012] [Indexed: 01/18/2023]
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Mascheretti S, Bureau A, Battaglia M, Simone D, Quadrelli E, Croteau J, Cellino MR, Giorda R, Beri S, Maziade M, Marino C. An assessment of gene-by-environment interactions in developmental dyslexia-related phenotypes. GENES BRAIN AND BEHAVIOR 2012; 12:47-55. [DOI: 10.1111/gbb.12000] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/26/2012] [Accepted: 10/24/2012] [Indexed: 01/02/2023]
Affiliation(s)
- S. Mascheretti
- The Academic Centre for the study of Behavioural Plasticity; Vita-Salute San Raffaele University; Milan; 20132; Italy
| | | | | | - D. Simone
- Department of Child Psychiatry; Scientific Institute Eugenio Medea; Bosisio Parini; Lecco; 23842; Italy
| | - E. Quadrelli
- Department of Child Psychiatry; Scientific Institute Eugenio Medea; Bosisio Parini; Lecco; 23842; Italy
| | - J. Croteau
- Centre de Recherche de l'Institut universitaire en santé mentale de Québec; Québec; G1J 2 G3; Canada
| | - M. R. Cellino
- Centro Regionale di Riferimento per i Disturbi dell'Apprendimento - CRRDA, ULSS 20; Verona; 37122; Italy
| | - R. Giorda
- Molecular Biology Laboratory; Scientific Institute Eugenio Medea; Bosisio Parini; Lecco; 23842; Italy
| | - S. Beri
- Molecular Biology Laboratory; Scientific Institute Eugenio Medea; Bosisio Parini; Lecco; 23842; Italy
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Putkinen V, Niinikuru R, Lipsanen J, Tervaniemi M, Huotilainen M. Fast measurement of auditory event-related potential profiles in 2-3-year-olds. Dev Neuropsychol 2012; 37:51-75. [PMID: 22292831 DOI: 10.1080/87565641.2011.615873] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Auditory discrimination, memory, and attention-related functions were investigated in healthy 2-3-year-olds by recording event-related potentials (ERPs) to changes in five auditory features and two types of novel sounds using the fast multifeature paradigm (MFP). ERP profiles consisting of the mismatch negativity (MMN), P3a, and prominent late discriminative negativities (LDN) were obtained, for the first time, from this age group in a considerably shorter time compared to the traditional paradigms. Statistically significant responses from individual children were obtained mainly for the novel sounds. Thus, the MFP shows promise as a time-efficient paradigm for investigating central auditory functions in toddlers.
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Affiliation(s)
- Vesa Putkinen
- Cognitive Brain Research Unit, Cognitive Science, Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
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Neuhoff N, Bruder J, Bartling J, Warnke A, Remschmidt H, Müller-Myhsok B, Schulte-Körne G. Evidence for the late MMN as a neurophysiological endophenotype for dyslexia. PLoS One 2012; 7:e34909. [PMID: 22606227 PMCID: PMC3351484 DOI: 10.1371/journal.pone.0034909] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 03/08/2012] [Indexed: 11/30/2022] Open
Abstract
Dyslexia affects 5–10% of school-aged children and is therefore one of the most common learning disorders. Research on auditory event related potentials (AERP), particularly the mismatch negativity (MMN) component, has revealed anomalies in individuals with dyslexia to speech stimuli. Furthermore, candidate genes for this disorder were found through molecular genetic studies. A current challenge for dyslexia research is to understand the interaction between molecular genetics and brain function, and to promote the identification of relevant endophenotypes for dyslexia. The present study examines MMN, a neurophysiological correlate of speech perception, and its potential as an endophenotype for dyslexia in three groups of children. The first group of children was clinically diagnosed with dyslexia, whereas the second group of children was comprised of their siblings who had average reading and spelling skills and were therefore “unaffected” despite having a genetic risk for dyslexia. The third group consisted of control children who were not related to the other groups and were also unaffected. In total, 225 children were included in the study. All children showed clear MMN activity to/da/−/ba/contrasts that could be separated into three distinct MMN components. Whilst the first two MMN components did not differentiate the groups, the late MMN component (300–700 ms) revealed significant group differences. The mean area of the late MMN was attenuated in both the dyslexic children and their unaffected siblings in comparison to the control children. This finding is indicative of analogous alterations of neurophysiological processes in children with dyslexia and those with a genetic risk for dyslexia, without a manifestation of the disorder. The present results therefore further suggest that the late MMN might be a potential endophenotype for dyslexia.
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Affiliation(s)
- Nina Neuhoff
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Munich, Munich, Germany
| | - Jennifer Bruder
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Munich, Munich, Germany
| | - Jürgen Bartling
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Munich, Munich, Germany
| | - Andreas Warnke
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Helmut Remschmidt
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Gießen and Marburg, Marburg, Germany
| | | | - Gerd Schulte-Körne
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Munich, Munich, Germany
- * E-mail:
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The mismatch negativity (MMN)--a unique window to disturbed central auditory processing in ageing and different clinical conditions. Clin Neurophysiol 2011; 123:424-58. [PMID: 22169062 DOI: 10.1016/j.clinph.2011.09.020] [Citation(s) in RCA: 268] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 09/16/2011] [Accepted: 09/20/2011] [Indexed: 12/14/2022]
Abstract
In this article, we review clinical research using the mismatch negativity (MMN), a change-detection response of the brain elicited even in the absence of attention or behavioural task. In these studies, the MMN was usually elicited by employing occasional frequency, duration or speech-sound changes in repetitive background stimulation while the patient was reading or watching videos. It was found that in a large number of different neuropsychiatric, neurological and neurodevelopmental disorders, as well as in normal ageing, the MMN amplitude was attenuated and peak latency prolonged. Besides indexing decreased discrimination accuracy, these effects may also reflect, depending on the specific stimulus paradigm used, decreased sensory-memory duration, abnormal perception or attention control or, most importantly, cognitive decline. In fact, MMN deficiency appears to index cognitive decline irrespective of the specific symptomatologies and aetiologies of the different disorders involved.
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36
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Dissection of genetic associations with language-related traits in population-based cohorts. J Neurodev Disord 2011; 3:365-73. [PMID: 21894572 PMCID: PMC3230763 DOI: 10.1007/s11689-011-9091-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 07/24/2011] [Indexed: 11/09/2022] Open
Abstract
Recent advances in the field of language-related disorders have led to the identification of candidate genes for specific language impairment (SLI) and dyslexia. Replication studies have been conducted in independent samples including population-based cohorts, which can be characterised for a large number of relevant cognitive measures. The availability of a wide range of phenotypes allows us to not only identify the most suitable traits for replication of genetic association but also to refine the associated cognitive trait. In addition, it is possible to test for pleiotropic effects across multiple phenotypes which could explain the extensive comorbidity observed across SLI, dyslexia and other neurodevelopmental disorders. The availability of genome-wide genotype data for such cohorts will facilitate this kind of analysis but important issues, such as multiple test corrections, have to be taken into account considering that small effect sizes are expected to underlie such associations.
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37
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Scerri TS, Morris AP, Buckingham LL, Newbury DF, Miller LL, Monaco AP, Bishop DV, Paracchini S. DCDC2, KIAA0319 and CMIP are associated with reading-related traits. Biol Psychiatry 2011; 70:237-45. [PMID: 21457949 PMCID: PMC3139836 DOI: 10.1016/j.biopsych.2011.02.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/18/2011] [Accepted: 02/05/2011] [Indexed: 10/25/2022]
Abstract
BACKGROUND Several susceptibility genes have been proposed for dyslexia (reading disability; RD) and specific language impairment (SLI). RD and SLI show comorbidity, but it is unclear whether a common genetic component is shared. METHODS We have investigated whether candidate genes for RD and SLI affect specific cognitive traits or have broad effect on cognition. We have analyzed common risk variants within RD (MRPL19/C2ORF3, KIAA0319, and DCDC2) and language impairment (CMIP and ATP2C2) candidate loci in the Avon Longitudinal Study of Parents and Children cohort (n = 3725), representing children born in southwest England in the early 1990s. RESULTS We detected associations between reading skills and KIAA0319, DCDC2, and CMIP. We show that DCDC2 is specifically associated with RD, whereas variants in CMIP and KIAA0319 are associated with reading skills across the ability range. The strongest associations were restricted to single-word reading and spelling measures, suggesting that these genes do not extend their effect to other reading and language-related skills. Inclusion of individuals with comorbidity tends to strengthen these associations. Our data do not support MRPL19/C2ORF3 as a locus involved in reading abilities nor CMIP/ATP2C2 as genes regulating language skills. CONCLUSIONS We provide further support for the role of KIAA0319 and DCDC2 in contributing to reading abilities and novel evidence that the language-disorder candidate gene CMIP is also implicated in reading processes. Additionally, we present novel data to evaluate the prevalence and comorbidity of RD and SLI, and we recommend not excluding individuals with comorbid RD and SLI when designing genetic association studies for RD.
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Affiliation(s)
- Tom S. Scerri
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK
| | - Andrew P. Morris
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK
| | | | | | - Laura L. Miller
- School of Social and Community Medicine, University of Bristol, UK
| | | | | | - Silvia Paracchini
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK,Address correspondence to Silvia Paracchini, D.Phil., Wellcome Trust Centre for Human Genetics, OX3 7BN Oxford, United Kingdom
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38
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Skiba T, Landi N, Wagner R, Grigorenko EL. In search of the perfect phenotype: an analysis of linkage and association studies of reading and reading-related processes. Behav Genet 2011; 41:6-30. [PMID: 21243420 PMCID: PMC3056345 DOI: 10.1007/s10519-011-9444-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 12/22/2010] [Indexed: 01/15/2023]
Abstract
Reading ability and specific reading disability (SRD) are complex traits involving several cognitive processes and are shaped by a complex interplay of genetic and environmental forces. Linkage studies of these traits have identified several susceptibility loci. Association studies have gone further in detecting candidate genes that might underlie these signals. These results have been obtained in samples of mainly European ancestry, which vary in their languages, inclusion criteria, and phenotype assessments. Such phenotypic heterogeneity across samples makes understanding the relationship between reading (dis)ability and reading-related processes and the genetic factors difficult; in addition, it may negatively influence attempts at replication. In moving forward, the identification of preferable phenotypes for future sample collection may improve the replicability of findings. This review of all published linkage and association results from the past 15 years was conducted to determine if certain phenotypes produce more replicable and consistent results than others.
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Affiliation(s)
| | - Nicole Landi
- Yale University & Haskins Laboratories, New Haven, CT, USA
| | | | - Elena L. Grigorenko
- Yale University, New Heaven, CT, USA
- Moscow State University, Moscow, Russia
- Columbia University, New York, NY, USA
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39
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Miller B, McCardle P. Moving closer to a public health model of language and learning disabilities: the role of genetics and the search for etiologies. Behav Genet 2011; 41:1-5. [PMID: 21229298 PMCID: PMC3897164 DOI: 10.1007/s10519-010-9439-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 12/22/2010] [Indexed: 01/27/2023]
Abstract
Continued progress in language and learning disabilities (LDs) research requires a renewed focused on issues of etiology. Genetics research forms a central tenet of such an agenda and is critical in clarifying relationships among oral language development, acquisition of literacy and mathematics, executive function skills, and comorbid conditions. For progress to be made, diversified efforts must continue to emphasize molecular and behavioral genetics (including quantitative genetics) approaches, in concert with multi-disciplinary and multi-modal projects, to provide an integrated understanding of the behavioral and biological manifestations of language and learning disabilities. Critically, increased efforts to include ethnic, socio-economic, and linguistically diverse participant samples across a range of developmental stages is required to meet the public health needs of learners in the US and across the world. Taken together, this body of work will continue to enhance our understanding of LDs and help us move toward a truly prevention based approach to language and learning disabilities.
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Affiliation(s)
- Brett Miller
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Blvd., Suite 4B05, MSC 7510, Bethesda, MD 20892, USA.
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