1
|
Zaki ZMM, Ali SA, Ghazali MM, Jam FA. Genetic Modifications of Developmental Dyslexia and Its Representation Using In Vivo, In Vitro Model. Glob Med Genet 2024; 11:76-85. [PMID: 38414980 PMCID: PMC10898997 DOI: 10.1055/s-0044-1781456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024] Open
Abstract
Dyslexia is a genetic and heritable disorder that has yet to discover the treatment of it, especially at the molecular and drug intervention levels. This review provides an overview of the current findings on the environmental and genetic factors involved in developmental dyslexia. The latest techniques used in diagnosing the disease and macromolecular factors findings may contribute to a higher degree of development in detangling the proper management and treatment for dyslexic individuals. Furthermore, this review tried to put together all the models used in the current dyslexia research for references in future studies that include animal models as well as in vitro models and how the previous research has provided consistent data across many years and regions. Thus, we suggest furthering the studies using an organoid model based on the existing gene polymorphism, pathways, and neuronal function input.
Collapse
Affiliation(s)
- Zakiyyah M M Zaki
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Siti A Ali
- Department of Electronic Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
- Centre for Healthcare Science and Technology, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
| | - Mazira M Ghazali
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Faidruz A Jam
- Department of Biochemistry, Faculty of Medicine, Manipal University College Malaysia, Melaka, Malaysia
| |
Collapse
|
2
|
Calì F, Di Blasi FD, Avola E, Vinci M, Musumeci A, Gloria A, Greco D, Raciti DR, Zagami A, Rizzo B, Città S, Federico C, Vetri L, Saccone S, Buono S. Specific Learning Disorders: Variation Analysis of 15 Candidate Genes in 9 Multiplex Families. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1503. [PMID: 37629793 PMCID: PMC10456226 DOI: 10.3390/medicina59081503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/13/2023] [Accepted: 08/20/2023] [Indexed: 08/27/2023]
Abstract
Background and Objectives: Specific Learning Disorder (SLD) is a complex neurobiological disorder characterized by a persistent difficult in reading (dyslexia), written expression (dysgraphia), and mathematics (dyscalculia). The hereditary and genetic component is one of the underlying causes of SLD, but the relationship between genes and the environment should be considered. Several genetic studies were performed in different populations to identify causative genes. Materials and Methods: Here, we show the analysis of 9 multiplex families with at least 2 individuals diagnosed with SLD per family, with a total of 37 persons, 21 of whom are young subjects with SLD, by means of Next-Generation Sequencing (NGS) to identify possible causative mutations in a panel of 15 candidate genes: CCPG1, CYP19A1, DCDC2, DGKI, DIP2A, DYM, GCFC2, KIAA0319, MC5R, MRPL19, NEDD4L, PCNT, PRMT2, ROBO1, and S100B. Results: We detected, in eight families out nine, SNP variants in the DGKI, DIP2A, KIAA0319, and PCNT genes, even if in silico analysis did not show any causative effect on this behavioral condition. In all cases, the mutation was transmitted by one of the two parents, thus excluding the case of de novo mutation. Moreover, the parent carrying the allelic variant transmitted to the children, in six out of seven families, reports language difficulties. Conclusions: Although the present results cannot be considered conclusive due to the limited sample size, the identification of genetic variants in the above genes can provide input for further research on the same, as well as on other genes/mutations, to better understand the genetic basis of this disorder, and from this perspective, to better understand also the neuropsychological and social aspects connected to this disorder, which affects an increasing number of young people.
Collapse
Affiliation(s)
- Francesco Calì
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | | | - Emanuela Avola
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Mirella Vinci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Antonino Musumeci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Angelo Gloria
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Donatella Greco
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Daniela Rita Raciti
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Alessandro Zagami
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Biagio Rizzo
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Santina Città
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Concetta Federico
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
| | - Luigi Vetri
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| | - Salvatore Saccone
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
| | - Serafino Buono
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.C.); (F.D.D.B.); (S.B.)
| |
Collapse
|
3
|
Kalashnikova TP, Satyukova MO, Anisimov GV, Karakulova YV. [Genetic background of dyslexia and dysgraphy in children]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:48-52. [PMID: 37315241 DOI: 10.17116/jnevro202312305148] [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: 06/16/2023]
Abstract
The review is devoted to one of the current problems of pediatric neurology - reading and writing disorders in children as part of a partial developmental disorder. With the development of neuroscience, the paradigm of «brain damage» in the understanding of a number of pathological conditions was replaced by the concept of «evolutionary neurology». The dominance of the ontogenetic approach caused the appearance of a new section in ICD-11 - «Neurodevelopmental disorders». Twenty-one genes associated with the acquisition of reading and writing skills have been identified. Modern studies demonstrate the connection of neuropsychological prerequisites for reading and writing, and clinical phenotypes of dyslexia with changes in specific loci. It is assumed that there are different molecular genetic bases for dyslexia and dysgraphia depending on ethnicity, orthographic features of language, including logographic features. Pleiotropy of genes is a cause of comorbidity of reading and writing disorders with attention deficit and hyperactivity disorder, specific speech articulation disorders, and dyscalculia. A key function of many of the identified genes is their involvement in the processes of neurogenesis. Their dysfunctions cause atypical neuronal migration, ectopic formation, inadequate axonal growth, and dendrite branching at the early stage of brain development. Morphological changes can distort the correct distribution and/or integration of linguistic stimuli in critical brain areas, leading to abnormalities in phonology, semantics, spelling, and general reading comprehension. The knowledge gained can form the basis for the development of risk models for dysgraphia and dyslexia formation and be used as a diagnostic and/or screening tool, which is important for evidence-based correction, optimization of academic performance, and mitigation of psychosocial consequences.
Collapse
Affiliation(s)
| | | | - G V Anisimov
- First Medico-Pedagogical Center «Lingua Bona», Perm, Russia
| | | |
Collapse
|
4
|
Price KM, Wigg KG, Eising E, Feng Y, Blokland K, Wilkinson M, Kerr EN, Guger SL, Fisher SE, Lovett MW, Strug LJ, Barr CL. Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities. Transl Psychiatry 2022; 12:495. [PMID: 36446759 PMCID: PMC9709072 DOI: 10.1038/s41398-022-02250-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 11/30/2022] Open
Abstract
Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10-2, threshold = 2.5 × 10-2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10-2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10-4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations.
Collapse
Affiliation(s)
- Kaitlyn M Price
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Else Eising
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Yu Feng
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Departments of Statistical Sciences and Computer Science, Faculty of Arts and Science and Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
5
|
Animal models of developmental dyslexia: Where we are and what we are missing. Neurosci Biobehav Rev 2021; 131:1180-1197. [PMID: 34699847 DOI: 10.1016/j.neubiorev.2021.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/21/2022]
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental disorder and the most common learning disability among both school-aged children and across languages. Recently, sensory and cognitive mechanisms have been reported to be potential endophenotypes (EPs) for DD, and nine DD-candidate genes have been identified. Animal models have been used to investigate the etiopathological pathways that underlie the development of complex traits, as they enable the effects of genetic and/or environmental manipulations to be evaluated. Animal research designs have also been linked to cutting-edge clinical research questions by capitalizing on the use of EPs. For the present scoping review, we reviewed previous studies of murine models investigating the effects of DD-candidate genes. Moreover, we highlighted the use of animal models as an innovative way to unravel new insights behind the pathophysiology of reading (dis)ability and to assess cutting-edge preclinical models.
Collapse
|
6
|
Price KM, Wigg KG, Feng Y, Blokland K, Wilkinson M, He G, Kerr EN, Carter TC, Guger SL, Lovett MW, Strug LJ, Barr CL. Genome-wide association study of word reading: Overlap with risk genes for neurodevelopmental disorders. GENES BRAIN AND BEHAVIOR 2020; 19:e12648. [PMID: 32108986 DOI: 10.1111/gbb.12648] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 01/28/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022]
Abstract
Reading disabilities (RD) are the most common neurocognitive disorder, affecting 5% to 17% of children in North America. These children often have comorbid neurodevelopmental/psychiatric disorders, such as attention deficit/hyperactivity disorder (ADHD). The genetics of RD and their overlap with other disorders is incompletely understood. To contribute to this, we performed a genome-wide association study (GWAS) for word reading. Then, using summary statistics from neurodevelopmental/psychiatric disorders, we computed polygenic risk scores (PRS) and used them to predict reading ability in our samples. This enabled us to test the shared aetiology between RD and other disorders. The GWAS consisted of 5.3 million single nucleotide polymorphisms (SNPs) and two samples; a family-based sample recruited for reading difficulties in Toronto (n = 624) and a population-based sample recruited in Philadelphia [Philadelphia Neurodevelopmental Cohort (PNC)] (n = 4430). The Toronto sample SNP-based analysis identified suggestive SNPs (P ~ 5 × 10-7 ) in the ARHGAP23 gene, which is implicated in neuronal migration/axon pathfinding. The PNC gene-based analysis identified significant associations (P < 2.72 × 10-6 ) for LINC00935 and CCNT1, located in the region of the KANSL2/CCNT1/LINC00935/SNORA2B/SNORA34/MIR4701/ADCY6 genes on chromosome 12q, with near significant SNP-based analysis. PRS identified significant overlap between word reading and intelligence (R2 = 0.18, P = 7.25 × 10-181 ), word reading and educational attainment (R2 = 0.07, P = 4.91 × 10-48 ) and word reading and ADHD (R2 = 0.02, P = 8.70 × 10-6 ; threshold for significance = 7.14 × 10-3 ). Overlap was also found between RD and autism spectrum disorder (ASD) as top-ranked genes were previously implicated in autism by rare and copy number variant analyses. These findings support shared risk between word reading, cognitive measures, educational outcomes and neurodevelopmental disorders, including ASD.
Collapse
Affiliation(s)
- Kaitlyn M Price
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yu Feng
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gengming He
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Tasha-Cate Carter
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Holland Bloorview Rehabilitation Hospital, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
7
|
Krafnick AJ, Evans TM. Neurobiological Sex Differences in Developmental Dyslexia. Front Psychol 2019; 9:2669. [PMID: 30687153 PMCID: PMC6336691 DOI: 10.3389/fpsyg.2018.02669] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 12/12/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding sex differences at the neurobiological level has become increasingly crucial in both basic and applied research. In the study of developmental dyslexia, early neuroimaging investigations were dominated by male-only or male-dominated samples, due at least in part to males being diagnosed more frequently. While recent studies more consistently balance the inclusion of both sexes, there has been little movement toward directly characterizing potential sex differences of the disorder. However, a string of recent work suggests that the brain basis of dyslexia may indeed be different in males and females. This potential sex difference has implications for existing models of dyslexia, and would inform approaches to the remediation of reading difficulties. This article reviews recent evidence for sex differences in dyslexia, discusses the impact these studies have on the understanding of the brain basis of dyslexia, and provides a framework for how these differential neuroanatomical profiles may develop.
Collapse
Affiliation(s)
- Anthony J Krafnick
- Psychology Department, Dominican University, River Forest, IL, United States
| | - Tanya M Evans
- Center for Advanced Study of Teaching and Learning, Curry School of Education and Human Development, University of Virginia, Charlottesville, VA, United States
| |
Collapse
|
8
|
Guidi LG, Velayos‐Baeza A, Martinez‐Garay I, Monaco AP, Paracchini S, Bishop DVM, Molnár Z. The neuronal migration hypothesis of dyslexia: A critical evaluation 30 years on. Eur J Neurosci 2018; 48:3212-3233. [PMID: 30218584 PMCID: PMC6282621 DOI: 10.1111/ejn.14149] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/06/2018] [Accepted: 08/13/2018] [Indexed: 12/29/2022]
Abstract
The capacity for language is one of the key features underlying the complexity of human cognition and its evolution. However, little is known about the neurobiological mechanisms that mediate normal or impaired linguistic ability. For developmental dyslexia, early postmortem studies conducted in the 1980s linked the disorder to subtle defects in the migration of neurons in the developing neocortex. These early studies were reinforced by human genetic analyses that identified dyslexia susceptibility genes and subsequent evidence of their involvement in neuronal migration. In this review, we examine recent experimental evidence that does not support the link between dyslexia and neuronal migration. We critically evaluate gene function studies conducted in rodent models and draw attention to the lack of robust evidence from histopathological and imaging studies in humans. Our review suggests that the neuronal migration hypothesis of dyslexia should be reconsidered, and the neurobiological basis of dyslexia should be approached with a fresh start.
Collapse
Affiliation(s)
- Luiz G. Guidi
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Isabel Martinez‐Garay
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Division of NeuroscienceSchool of BiosciencesCardiff UniversityCardiffUK
| | | | | | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
| |
Collapse
|
9
|
The influence of DCDC2 risk genetic variants on reading: Testing main and haplotypic effects. Neuropsychologia 2018; 130:52-58. [PMID: 29803723 DOI: 10.1016/j.neuropsychologia.2018.05.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 04/17/2018] [Accepted: 05/23/2018] [Indexed: 12/28/2022]
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental heritable disorder. Among DD candidate genes, DCDC2 is one of the most replicated, with rs793862, READ1 and rs793842 likely contribute to phenotypic variability in reading (dis)ability. In this study, we tested the effects of these genetic variants on DD as a categorical trait and on quantitative reading-related measures in a sample of 555 Italian nuclear families with 930 offspring, of which 687 were diagnosed with DD. We conducted both single-marker and haplotype analyses, finding that the READ1-deletion was significantly associated with reading, whereas no significant haplotype associations were found. Our findings add further evidence to support the hypothesis of a DCDC2 contribution to inter-individual variation in distinct indicators of reading (dis)ability in transparent languages (i.e., reading accuracy and speed), suggesting a potential pleiotropic effect.
Collapse
|
10
|
Rendall AR, Perrino PA, LoTurco JJ, Fitch RH. Evaluation of visual motion perception ability in mice with knockout of the dyslexia candidate susceptibility gene Dcdc2. GENES BRAIN AND BEHAVIOR 2018; 18:e12450. [PMID: 29232042 DOI: 10.1111/gbb.12450] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 12/08/2017] [Accepted: 12/08/2017] [Indexed: 12/17/2022]
Abstract
Developmental dyslexia is a heritable disability characterized by difficulties in learning to read and write. The neurobiological and genetic mechanisms underlying dyslexia remain poorly understood; however, several dyslexia candidate risk genes have been identified. One of these candidate risk genes-doublecortin domain containing 2 (DCDC2)-has been shown to play a role in neuronal migration and cilia function. At a behavioral level, variants of DCDC2 have been associated with impairments in phonological processing, working memory and reading speed. Additionally, a specific mutation in DCDC2 has been strongly linked to deficits in motion perception-a skill subserving reading abilities. To further explore the relationship between DCDC2 and dyslexia, a genetic knockout (KO) of the rodent homolog of DCDC2 (Dcdc2) was created. Initial studies showed that Dcdc2 KOs display deficits in auditory processing and working memory. The current study was designed to evaluate the association between DCDC2 and motion perception, as these skills have not yet been assessed in the Dcdc2 KO mouse model. We developed a novel motion perception task, utilizing touchscreen technology and operant conditioning. Dcdc2 KOs displayed deficits on the Pairwise Discrimination task specifically as motion was added to visual stimuli. Following behavioral assessment, brains were histologically prepared for neuroanatomical analysis of the lateral geniculate nucleus (LGN). The cumulative distribution showed that Dcdc2 KOs exhibited more small neurons and fewer larger neurons in the LGN. Results compliment findings that DCDC2 genetic alteration results in anomalies in visual motion pathways in a subpopulation of dyslexic patients.
Collapse
Affiliation(s)
- A R Rendall
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - P A Perrino
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - J J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - R H Fitch
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| |
Collapse
|
11
|
Guidi LG, Mattley J, Martinez-Garay I, Monaco AP, Linden JF, Velayos-Baeza A, Molnár Z. Knockout Mice for Dyslexia Susceptibility Gene Homologs KIAA0319 and KIAA0319L have Unaffected Neuronal Migration but Display Abnormal Auditory Processing. Cereb Cortex 2017; 27:5831-5845. [PMID: 29045729 PMCID: PMC5939205 DOI: 10.1093/cercor/bhx269] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Developmental dyslexia is a neurodevelopmental disorder that affects reading ability caused by genetic and non-genetic factors. Amongst the susceptibility genes identified to date, KIAA0319 is a prime candidate. RNA-interference experiments in rats suggested its involvement in cortical migration but we could not confirm these findings in Kiaa0319-mutant mice. Given its homologous gene Kiaa0319L (AU040320) has also been proposed to play a role in neuronal migration, we interrogated whether absence of AU040320 alone or together with KIAA0319 affects migration in the developing brain. Analyses of AU040320 and double Kiaa0319;AU040320 knockouts (dKO) revealed no evidence for impaired cortical lamination, neuronal migration, neurogenesis or other anatomical abnormalities. However, dKO mice displayed an auditory deficit in a behavioral gap-in-noise detection task. In addition, recordings of click-evoked auditory brainstem responses revealed suprathreshold deficits in wave III amplitude in AU040320-KO mice, and more general deficits in dKOs. These findings suggest that absence of AU040320 disrupts firing and/or synchrony of activity in the auditory brainstem, while loss of both proteins might affect both peripheral and central auditory function. Overall, these results stand against the proposed role of KIAA0319 and AU040320 in neuronal migration and outline their relationship with deficits in the auditory system.
Collapse
Affiliation(s)
- Luiz G Guidi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Jane Mattley
- Ear Institute, University College London, London WC1X 8EE, UK
| | - Isabel Martinez-Garay
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Anthony P Monaco
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
- Current address: Office of the President, Ballou Hall, Tufts University, Medford, MA 02155, USA
| | - Jennifer F Linden
- Ear Institute, University College London, London WC1X 8EE, UK
- Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E 6BT, UK
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK
| |
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
Waye MMY, Poo LK, Ho CSH. Study of Genetic Association With DCDC2 and Developmental Dyslexia in Hong Kong Chinese Children. Clin Pract Epidemiol Ment Health 2017; 13:104-114. [PMID: 29081827 PMCID: PMC5633722 DOI: 10.2174/1745017901713010104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/21/2017] [Accepted: 07/25/2017] [Indexed: 11/30/2022]
Abstract
Background: Doublecortin domain-containing 2 (DCDC2) is a doublecortin domain-containing gene family member and the doublecortin domain has been demonstrated to bind to tubulin and enhance microtubule polymerization. It has been associated with developmental dyslexia and this protein family member is thought to function in neuronal migration where it may affect the signaling of primary cilia. Objectives: The objective of the study is to find out if there is any association of genetic variants of DCDC2 with developmental dyslexia in Chinese children from Hong Kong. Methods: The dyslexic children were diagnosed as developmental dyslexia (DD) using the Hong Kong Test of Specific Learning Difficulties in Reading and Writing (HKT-SpLD) by the Department of Health, Hong Kong. Saliva specimens were collected and their genotypes of DCDC2 were studied by DNA sequencing or TaqMan Real Time PCR Assays. Results: The most significant marker is rs6940827 which is associated with DD with nominal p-value (0.011). However, this marker did not remain significant after multiple testing corrections and the adjusted p-value from permutation test was 0.1329. Using sliding window haplotype analysis, several haplotypes were found to be nominally associated with DD. The smallest nominal p values was 0.0036 (rs2996452-rs1318700, C-A). However, none of the p values could withstand the multiple testing corrections. Conclusion: Despite early findings that DCDC2 is a strong candidate for developmental dyslexia and that some of the genetic variants have been linked to brain structure and functions, our findings showed that DCDC2 is not strongly associated with dyslexia.
Collapse
Affiliation(s)
- Mary M Y Waye
- The Nethersole School of Nursing, The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong
| | - Lim K Poo
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong
| | - Connie S-H Ho
- Department of Psychology, The University of Hong Kong, Hong Kong
| |
Collapse
|
14
|
The role of READ1 and KIAA0319 genetic variations in developmental dyslexia: testing main and interactive effects. J Hum Genet 2017; 62:949-955. [DOI: 10.1038/jhg.2017.80] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 12/23/2022]
|
15
|
Ayanlaja AA, Xiong Y, Gao Y, Ji G, Tang C, Abdikani Abdullah Z, Gao D. Distinct Features of Doublecortin as a Marker of Neuronal Migration and Its Implications in Cancer Cell Mobility. Front Mol Neurosci 2017; 10:199. [PMID: 28701917 PMCID: PMC5487455 DOI: 10.3389/fnmol.2017.00199] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/06/2017] [Indexed: 12/16/2022] Open
Abstract
Neuronal migration is a critical process in the development of the nervous system. Defects in the migration of the neurons are associated with diseases like lissencephaly, subcortical band heterotopia (SBH), and pachygyria. Doublecortin (DCX) is an essential factor in neurogenesis and mutations in this protein impairs neuronal migration leading to several pathological conditions. Although, DCX is capable of modulating and stabilizing microtubules (MTs) to ensure effective migration, the mechanisms involved in executing these functions remain poorly understood. Meanwhile, there are existing gaps regarding the processes that underlie tumor initiation and progression into cancer as well as the ability to migrate and invade normal cells. Several studies suggest that DCX is involved in cancer metastasis. Unstable interactions between DCX and MTs destabilizes cytoskeletal organization leading to disorganized movements of cells, a process which may be implicated in the uncontrolled migration of cancer cells. However, the underlying mechanism is complex and require further clarification. Therefore, exploring the importance and features known up to date about this molecule will broaden our understanding and shed light on potential therapeutic approaches for the associated neurological diseases. This review summarizes current knowledge about DCX, its features, functions, and relationships with other proteins. We also present an overview of its role in cancer cells and highlight the importance of studying its gene mutations.
Collapse
Affiliation(s)
- Abiola A Ayanlaja
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - Ye Xiong
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - Yue Gao
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - GuangQuan Ji
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - Chuanxi Tang
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - Zamzam Abdikani Abdullah
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| | - DianShuai Gao
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical UniversityXuzhou, China
| |
Collapse
|
16
|
Knockdown of Dyslexia-Gene Dcdc2 Interferes with Speech Sound Discrimination in Continuous Streams. J Neurosci 2017; 36:4895-906. [PMID: 27122044 DOI: 10.1523/jneurosci.4202-15.2016] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 03/29/2016] [Indexed: 01/04/2023] Open
Abstract
UNLABELLED Dyslexia is the most common developmental language disorder and is marked by deficits in reading and phonological awareness. One theory of dyslexia suggests that the phonological awareness deficit is due to abnormal auditory processing of speech sounds. Variants in DCDC2 and several other neural migration genes are associated with dyslexia and may contribute to auditory processing deficits. In the current study, we tested the hypothesis that RNAi suppression of Dcdc2 in rats causes abnormal cortical responses to sound and impaired speech sound discrimination. In the current study, rats were subjected in utero to RNA interference targeting of the gene Dcdc2 or a scrambled sequence. Primary auditory cortex (A1) responses were acquired from 11 rats (5 with Dcdc2 RNAi; DC-) before any behavioral training. A separate group of 8 rats (3 DC-) were trained on a variety of speech sound discrimination tasks, and auditory cortex responses were acquired following training. Dcdc2 RNAi nearly eliminated the ability of rats to identify specific speech sounds from a continuous train of speech sounds but did not impair performance during discrimination of isolated speech sounds. The neural responses to speech sounds in A1 were not degraded as a function of presentation rate before training. These results suggest that A1 is not directly involved in the impaired speech discrimination caused by Dcdc2 RNAi. This result contrasts earlier results using Kiaa0319 RNAi and suggests that different dyslexia genes may cause different deficits in the speech processing circuitry, which may explain differential responses to therapy. SIGNIFICANCE STATEMENT Although dyslexia is diagnosed through reading difficulty, there is a great deal of variation in the phenotypes of these individuals. The underlying neural and genetic mechanisms causing these differences are still widely debated. In the current study, we demonstrate that suppression of a candidate-dyslexia gene causes deficits on tasks of rapid stimulus processing. These animals also exhibited abnormal neural plasticity after training, which may be a mechanism for why some children with dyslexia do not respond to intervention. These results are in stark contrast to our previous work with a different candidate gene, which caused a different set of deficits. Our results shed some light on possible neural and genetic mechanisms causing heterogeneity in the dyslexic population.
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
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]
|
19
|
Martinez-Garay I, Guidi LG, Holloway ZG, Bailey MAG, Lyngholm D, Schneider T, Donnison T, Butt SJB, Monaco AP, Molnár Z, Velayos-Baeza A. Normal radial migration and lamination are maintained in dyslexia-susceptibility candidate gene homolog Kiaa0319 knockout mice. Brain Struct Funct 2017; 222:1367-1384. [PMID: 27510895 PMCID: PMC5368214 DOI: 10.1007/s00429-016-1282-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/26/2016] [Indexed: 12/18/2022]
Abstract
Developmental dyslexia is a common disorder with a strong genetic component, but the underlying molecular mechanisms are still unknown. Several candidate dyslexia-susceptibility genes, including KIAA0319, DYX1C1, and DCDC2, have been identified in humans. RNA interference experiments targeting these genes in rat embryos have shown impairments in neuronal migration, suggesting that defects in radial cortical migration could be involved in the disease mechanism of dyslexia. Here we present the first characterisation of a Kiaa0319 knockout mouse line. Animals lacking KIAA0319 protein do not show anatomical abnormalities in any of the layered structures of the brain. Neurogenesis and radial migration of cortical projection neurons are not altered, and the intrinsic electrophysiological properties of Kiaa0319-deficient neurons do not differ from those of wild-type neurons. Kiaa0319 overexpression in cortex delays radial migration, but does not affect final neuronal position. However, knockout animals show subtle differences suggesting possible alterations in anxiety-related behaviour and in sensorimotor gating. Our results do not reveal a migration disorder in the mouse model, adding to the body of evidence available for Dcdc2 and Dyx1c1 that, unlike in the rat in utero knockdown models, the dyslexia-susceptibility candidate mouse homolog genes do not play an evident role in neuronal migration. However, KIAA0319 protein expression seems to be restricted to the brain, not only in early developmental stages but also in adult mice, indicative of a role of this protein in brain function. The constitutive and conditional knockout lines reported here will be useful tools for further functional analyses of Kiaa0319.
Collapse
Affiliation(s)
- Isabel Martinez-Garay
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Division of Neuroscience, School of Biosciences, Cardiff University, Cardiff, UK
| | - Luiz G Guidi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Zoe G Holloway
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Melissa A G Bailey
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Daniel Lyngholm
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Tomasz Schneider
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Timothy Donnison
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Simon J B Butt
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Anthony P Monaco
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Office of the President, Ballou Hall, Tufts University, Medford, MA, 02155, USA.
| | - Zoltán Molnár
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, OX1 3QX, UK.
| | - Antonio Velayos-Baeza
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
| |
Collapse
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
Mascheretti S, Trezzi V, Giorda R, Boivin M, Plourde V, Vitaro F, Brendgen M, Dionne G, Marino C. Complex effects of dyslexia risk factors account for ADHD traits: evidence from two independent samples. J Child Psychol Psychiatry 2017; 58:75-82. [PMID: 27501527 DOI: 10.1111/jcpp.12612] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/13/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Developmental dyslexia (DD) and attention deficit/hyperactivity disorder (ADHD) are among the most common neurodevelopmental disorders, whose etiology involves multiple risk factors. DD and ADHD co-occur in the same individuals much more often than would be expected by chance. Several studies have found significant bivariate heritability, and specific genes associated with either DD or ADHD have been investigated for association in the other disorder. Moreover, there are likely to be gene-by-gene and gene-by-environment interaction effects (G × G and G × E, respectively) underlying the comorbidity between DD and ADHD. We investigated the pleiotropic effects of 19 SNPs spanning five DD genes (DYX1C1, DCDC2, KIAA0319, ROBO1, and GRIN2B) and seven DD environmental factors (smoke, miscarriage, birth weight, breastfeeding, parental age, socioeconomic status, and parental education) for main, either (a) genetic or (b) environmental, (c) G × G, and (d) G × E upon inattention and hyperactivity/impulsivity. We then attempted replication of these findings in an independent twin cohort. METHODS Marker-trait association was analyzed by implementing the Quantitative Transmission Disequilibrium Test (QTDT). Environmental associations were tested by partial correlations. G × G were investigated by a general linear model equation and a family-based association test. G × E were analyzed through a general test for G × E in sib pair-based association analysis of quantitative traits. RESULTS DCDC2-rs793862 was associated with hyperactivity/impulsivity via G × G (KIAA0319) and G × E (miscarriage). Smoke was significantly correlated with hyperactivity/impulsivity. We replicated the DCDC2 × KIAA0319 interaction upon hyperactivity/impulsivity in the twin cohort. CONCLUSIONS DD genetic (DCDC2) and environmental factors (smoke and miscarriage) underlie ADHD traits supporting a potential pleiotropic effect.
Collapse
Affiliation(s)
- Sara Mascheretti
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Vittoria Trezzi
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Roberto Giorda
- Molecular Biology Lab, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Michel Boivin
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada.,Institute of Genetic, Neurobiological, and Social Foundations of Child Development, Tomsk State University, Tomsk, Russian Federation
| | - Vickie Plourde
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada
| | - Frank Vitaro
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Department of Psycho-Education, GRIP, University of Montreal, Montreal, QC, Canada
| | - Mara Brendgen
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada
| | - Ginette Dionne
- Research Unit on Children's Psychosocial Maladjustment, Montréal, QC, Canada.,Ecole de Psychologie, Laval University, Québec, QC, Canada
| | - Cecilia Marino
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy.,Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
22
|
Neurogenetics of developmental dyslexia: from genes to behavior through brain neuroimaging and cognitive and sensorial mechanisms. Transl Psychiatry 2017; 7:e987. [PMID: 28045463 PMCID: PMC5545717 DOI: 10.1038/tp.2016.240] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/15/2016] [Indexed: 01/18/2023] Open
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental deficit characterized by impaired reading acquisition, in spite of adequate neurological and sensorial conditions, educational opportunities and normal intelligence. Despite the successful characterization of DD-susceptibility genes, we are far from understanding the molecular etiological pathways underlying the development of reading (dis)ability. By focusing mainly on clinical phenotypes, the molecular genetics approach has yielded mixed results. More optimally reduced measures of functioning, that is, intermediate phenotypes (IPs), represent a target for researching disease-associated genetic variants and for elucidating the underlying mechanisms. Imaging data provide a viable IP for complex neurobehavioral disorders and have been extensively used to investigate both morphological, structural and functional brain abnormalities in DD. Performing joint genetic and neuroimaging studies in humans is an emerging strategy to link DD-candidate genes to the brain structure and function. A limited number of studies has already pursued the imaging-genetics integration in DD. However, the results are still not sufficient to unravel the complexity of the reading circuit due to heterogeneous study design and data processing. Here, we propose an interdisciplinary, multilevel, imaging-genetic approach to disentangle the pathways from genes to behavior. As the presence of putative functional genetic variants has been provided and as genetic associations with specific cognitive/sensorial mechanisms have been reported, new hypothesis-driven imaging-genetic studies must gain momentum. This approach would lead to the optimization of diagnostic criteria and to the early identification of 'biologically at-risk' children, supporting the definition of adequate and well-timed prevention strategies and the implementation of novel, specific remediation approach.
Collapse
|
23
|
Predicting early signs of dyslexia at a preliterate age by combining behavioral assessment with structural MRI. Neuroimage 2016; 143:378-386. [PMID: 27608602 DOI: 10.1016/j.neuroimage.2016.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/23/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only. METHODS We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade. RESULTS The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%). The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p<.05). CONCLUSIONS Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role.
Collapse
|
24
|
Zhang Y, Li J, Song S, Tardif T, Burmeister M, Villafuerte SM, Su M, McBride C, Shu H. Association of DCDC2 Polymorphisms with Normal Variations in Reading Abilities in a Chinese Population. PLoS One 2016; 11:e0153603. [PMID: 27100778 PMCID: PMC4839751 DOI: 10.1371/journal.pone.0153603] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 03/31/2016] [Indexed: 11/19/2022] Open
Abstract
The doublecortin domain-containing 2 (DCDC2) gene, which is located on chromosome 6p22.1, has been widely suggested to be a candidate gene for dyslexia, but its role in typical reading development over time remains to be clarified. In the present study, we explored the role of DCDC2 in contributing to the individual differences in reading development from ages 6 to 11 years by analysing data from 284 unrelated children who were participating in the Chinese Longitudinal Study of Reading Development (CLSRD). The associations of eight single nucleotide polymorphisms (SNPs) in DCDC2 with the latent intercept and slope of children's reading scores were examined in the first step. There was significant support for an association of rs807724 with the intercept for the reading comprehension measure of reading fluency, and the minor "G" allele was associated with poor reading performance. Next, we further tested the rs807724 SNP in association with the reading ability at each tested time and revealed that, in addition to significant associations with the two main reading measures (reading fluency and Chinese character reading) over multiple testing occasions, this SNP also showed associations with reading-related cognitive skills, including morphological production, orthographic judgment and phonological processing skills (rapid number naming, phoneme deletion, and tone detection). This study provides support for DCDC2 as a risk gene for reading disability and suggests that this gene is also operative for typical reading development in the Han population.
Collapse
Affiliation(s)
- Yuping Zhang
- Department of Psychology, Chengdu Medical College, Chengdu, China
- ResearchCenter for Applied Psychology of Sichuan, Chengdu Medical College, Chengdu, China
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Jun Li
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Shuang Song
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Twila Tardif
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Margit Burmeister
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sandra M. Villafuerte
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mengmeng Su
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Catherine McBride
- Department of Psychology, The Chinese University of Hong Kong, Hong Kong, China
| | - Hua Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| |
Collapse
|
25
|
Jeruschke S, Jeruschke K, DiStasio A, Karaterzi S, Büscher AK, Nalbant P, Klein-Hitpass L, Hoyer PF, Weiss J, Stottmann RW, Weber S. Everolimus Stabilizes Podocyte Microtubules via Enhancing TUBB2B and DCDC2 Expression. PLoS One 2015; 10:e0137043. [PMID: 26331477 PMCID: PMC4557973 DOI: 10.1371/journal.pone.0137043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 08/12/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Glomerular podocytes are highly differentiated cells that are key components of the kidney filtration units. The podocyte cytoskeleton builds the basis for the dynamic podocyte cytoarchitecture and plays a central role for proper podocyte function. Recent studies implicate that immunosuppressive agents including the mTOR-inhibitor everolimus have a protective role directly on the stability of the podocyte actin cytoskeleton. In contrast, a potential stabilization of microtubules by everolimus has not been studied so far. METHODS To elucidate mechanisms underlying mTOR-inhibitor mediated cytoskeletal rearrangements, we carried out microarray gene expression studies to identify target genes and corresponding pathways in response to everolimus. We analyzed the effect of everolimus in a puromycin aminonucleoside experimental in vitro model of podocyte injury. RESULTS Upon treatment with puromycin aminonucleoside, microarray analysis revealed gene clusters involved in cytoskeletal reorganization, cell adhesion, migration and extracellular matrix composition to be affected. Everolimus was capable of protecting podocytes from injury, both on transcriptional and protein level. Rescued genes included tubulin beta 2B class IIb (TUBB2B) and doublecortin domain containing 2 (DCDC2), both involved in microtubule structure formation in neuronal cells but not identified in podocytes so far. Validating gene expression data, Western-blot analysis in cultured podocytes demonstrated an increase of TUBB2B and DCDC2 protein after everolimus treatment, and immunohistochemistry in healthy control kidneys confirmed a podocyte-specific expression. Interestingly, Tubb2bbrdp/brdp mice revealed a delay in glomerular podocyte development as showed by podocyte-specific markers Wilm's tumour 1, Podocin, Nephrin and Synaptopodin. CONCLUSIONS Taken together, our study suggests that off-target, non-immune mediated effects of the mTOR-inhibitor everolimus on the podocyte cytoskeleton might involve regulation of microtubules, revealing a potential novel role of TUBB2B and DCDC2 in glomerular podocyte development.
Collapse
Affiliation(s)
- Stefanie Jeruschke
- Pediatric Nephrology, Pediatrics II, University Hospital Essen, Essen, Germany
- * E-mail:
| | - Kay Jeruschke
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Duesseldorf, Germany
| | - Andrew DiStasio
- Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Sinem Karaterzi
- Pediatric Nephrology, Pediatrics II, University Hospital Essen, Essen, Germany
| | - Anja K. Büscher
- Pediatric Nephrology, Pediatrics II, University Hospital Essen, Essen, Germany
| | - Perihan Nalbant
- Center for Medical Biotechnology, Molecular Cell Biology, University of Duisburg-Essen, Essen, Germany
| | | | - Peter F. Hoyer
- Pediatric Nephrology, Pediatrics II, University Hospital Essen, Essen, Germany
| | - Jürgen Weiss
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Duesseldorf, Germany
| | - Rolf W. Stottmann
- Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Stefanie Weber
- Pediatric Nephrology, Pediatrics II, University Hospital Essen, Essen, Germany
| |
Collapse
|
26
|
Abstract
Dyslexia is a specific impairment in reading that affects 1 in 10 people. Previous studies have failed to isolate a single cause of the disorder, but several candidate genes have been reported. We measured motion perception in two groups of dyslexics, with and without a deletion within the DCDC2 gene, a risk gene for dyslexia. We found impairment for motion particularly strong at high spatial frequencies in the population carrying the deletion. The data suggest that deficits in motion processing occur in a specific genotype, rather than the entire dyslexia population, contributing to the large variability in impairment of motion thresholds in dyslexia reported in the literature.
Collapse
|
27
|
Che A, Truong DT, Fitch RH, LoTurco JJ. Mutation of the Dyslexia-Associated Gene Dcdc2 Enhances Glutamatergic Synaptic Transmission Between Layer 4 Neurons in Mouse Neocortex. Cereb Cortex 2015; 26:3705-3718. [PMID: 26250775 DOI: 10.1093/cercor/bhv168] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Variants in DCDC2 have been associated with reading disability in humans, and targeted mutation of Dcdc2 in mice causes impairments in both learning and sensory processing. In this study, we sought to determine whether Dcdc2 mutation affects functional synaptic circuitry in neocortex. We found mutation in Dcdc2 resulted in elevated spontaneous and evoked glutamate release from neurons in somatosensory cortex. The probability of release was decreased to wild-type level by acute application of N-methyl-d-aspartate receptor (NMDAR) antagonists when postsynaptic NMDARs were blocked by intracellular MK-801, and could not be explained by elevated ambient glutamate, suggesting altered, nonpostsynaptic NMDAR activation in the mutants. In addition, we determined that the increased excitatory transmission was present at layer 4-layer 4 but not thalamocortical connections in Dcdc2 mutants, and larger evoked synaptic release appeared to enhance the NMDAR-mediated effect. These results demonstrate an NMDAR activation-gated, increased functional excitatory connectivity between layer 4 lateral connections in somatosensory neocortex of the mutants, providing support for potential changes in cortical connectivity and activation resulting from mutation of dyslexia candidate gene Dcdc2.
Collapse
Affiliation(s)
- Alicia Che
- Department of Physiology and Neurobiology.,Current address: Weill Cornell Medical College, Brain & Mind Research Institute, New York, NY 10021, USA
| | - Dongnhu T Truong
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.,Current address: Department of Pediatrics, Yale University, New Haven, CT 06520, USA
| | - R Holly Fitch
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA
| | | |
Collapse
|
28
|
The role of DCDC2 genetic variants and low socioeconomic status in vulnerability to attention problems. Eur Child Adolesc Psychiatry 2015; 24:309-18. [PMID: 25012462 DOI: 10.1007/s00787-014-0580-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
Both genetic and socio-demographic factors influence the risk for behavioral problems in the developmental age. Genetic studies indicate that shared genetic factors partially contribute to behavioral and learning problems, in particular reading disabilities (RD). For the first time, we explore the conjoint role of DCDC2 gene, an identified RD candidate gene, and socioeconomic status (SES) upon behavioral phenotypes in a general population of Italian children. Two of the most replicated DCDC2 markers [i.e., regulatory element associated with dyslexia 1 (READ1), rs793862] were genotyped in 631 children (boys = 314; girls = 317) aged 11-14 years belonging to a community-based sample. Main and interactive effects were tested by MANOVA for each combination of DCDC2 genotypes and socioeconomic status upon emotional and behavioral phenotypes, assessed by Child Behavior Check-List/6-18. The two-way MANOVA (Bonferroni corrected p value = 0.01) revealed a trend toward significance of READ1(4) effect (F = 2.39; p = 0.016), a significant main effect of SES (F = 3.01; p = 0.003) and interactive effect of READ1(4) × SES (F = 2.65; p = 0.007) upon behavioral measures, showing higher attention problems scores among subjects 'READ1(4+) and low SES' compared to all other groups (p values range 0.00003-0.0004). ANOVAs stratified by gender confirmed main and interactive effects among girls, but not boys. Among children exposed to low socioeconomic level, READ1 genetic variant targets the worst outcome in children's attention.
Collapse
|
29
|
Gori S, Mascheretti S, Giora E, Ronconi L, Ruffino M, Quadrelli E, Facoetti A, Marino C. The DCDC2 Intron 2 Deletion Impairs Illusory Motion Perception Unveiling the Selective Role of Magnocellular-Dorsal Stream in Reading (Dis)ability. Cereb Cortex 2014; 25:1685-95. [PMID: 25270309 DOI: 10.1093/cercor/bhu234] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Simone Gori
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, 35131 Padua, Italy Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy
| | - Sara Mascheretti
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy
| | - Enrico Giora
- Faculty of Psychology, "Vita-Salute" San Raffaele University, 20132 Milan, Italy
| | - Luca Ronconi
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, 35131 Padua, Italy Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy
| | - Milena Ruffino
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy
| | - Ermanno Quadrelli
- Department of Psychology, University of Milan-Bicocca, 20126 Milan, Italy
| | - Andrea Facoetti
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, 35131 Padua, Italy Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy
| | - Cecilia Marino
- Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, 23842 Bosisio Parini, Lecco, Italy Centre de Recherche de L'Institut Universitaire en Santé Mentale de Québec, Québec, QC, Canada G1J 2G3 Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, QC, Canada G1V 0A6
| |
Collapse
|
30
|
Truong DT, Che A, Rendall AR, Szalkowski CE, LoTurco JJ, Galaburda AM, Holly Fitch R. Mutation of Dcdc2 in mice leads to impairments in auditory processing and memory ability. GENES BRAIN AND BEHAVIOR 2014; 13:802-11. [PMID: 25130614 DOI: 10.1111/gbb.12170] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 07/14/2014] [Accepted: 08/07/2014] [Indexed: 12/12/2022]
Abstract
Dyslexia is a complex neurodevelopmental disorder characterized by impaired reading ability despite normal intellect, and is associated with specific difficulties in phonological and rapid auditory processing (RAP), visual attention and working memory. Genetic variants in Doublecortin domain-containing protein 2 (DCDC2) have been associated with dyslexia, impairments in phonological processing and in short-term/working memory. The purpose of this study was to determine whether sensory and behavioral impairments can result directly from mutation of the Dcdc2 gene in mice. Several behavioral tasks, including a modified pre-pulse inhibition paradigm (to examine auditory processing), a 4/8 radial arm maze (to assess/dissociate working vs. reference memory) and rotarod (to examine sensorimotor ability and motor learning), were used to assess the effects of Dcdc2 mutation. Behavioral results revealed deficits in RAP, working memory and reference memory in Dcdc2(del2/del2) mice when compared with matched wild types. Current findings parallel clinical research linking genetic variants of DCDC2 with specific impairments of phonological processing and memory ability.
Collapse
Affiliation(s)
- D T Truong
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, Storrs, CT
| | | | | | | | | | | | | |
Collapse
|
31
|
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.
Collapse
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
| |
Collapse
|
32
|
Marino C, Scifo P, Della Rosa PA, Mascheretti S, Facoetti A, Lorusso ML, Giorda R, Consonni M, Falini A, Molteni M, Gruen JR, Perani D. The DCDC2/intron 2 deletion and white matter disorganization: focus on developmental dyslexia. Cortex 2014; 57:227-43. [PMID: 24926531 DOI: 10.1016/j.cortex.2014.04.016] [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] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 04/20/2014] [Accepted: 04/25/2014] [Indexed: 01/21/2023]
Abstract
INTRODUCTION The DCDC2 gene is involved in neuronal migration. Heterotopias have been found within the white matter of DCDC2-knockdown rats. A deletion in DCDC2/intron 2 (DCDC2d), which encompasses a regulatory region named 'regulatory element associated with dyslexia 1' (READ1), increases the risk for dyslexia. We hypothesized that DCDC2d can be associated to alterations of the white matter structure in general and in dyslexic brains. METHODS Based on a full-factorial analysis of covariance (ANCOVA) model, we investigated voxel-based diffusion tensor imaging (VB-DTI) data of four groups of subjects: dyslexia with/without DCDC2d, and normal readers with/without DCDC2d. We also tested DCDC2d effects upon correlation patterns between fractional anisotropy (FA) and reading scores. RESULTS We found that FA was reduced in the left arcuate fasciculus and splenium of the corpus callosum in subjects with versus without DCDC2d, irrespective of dyslexia. Subjects with dyslexia and DCDC2d showed reduced FA, mainly in the left hemisphere and in the corpus callosum; their counterpart without DCDC2d showed similar FA alterations. Noteworthy, a conjunction analysis in impaired readers revealed common regions with lower FA mainly in the left hemisphere. When we compared subjects with dyslexia with versus without DCDC2d, we found lower FA in the inferior longitudinal fasciculus and genu of the corpus callosum, bilaterally. Normal readers with versus without DCDC2d had FA increases and decreases in both the right and left hemisphere. DISCUSSION The major contribution of our study was to provide evidence relating genes, brain and behaviour. Overall, our findings support the hypothesis that DCDC2d is associated with altered FA. In normal readers, DCDC2-related anatomical patterns may mark some developmental cognitive vulnerability to learning disabilities. In subjects with dyslexia, DCDC2d accounted for both common - mainly located in the left hemisphere - and unique - a more severe and extended pattern - alterations of white matter fibre tracts.
Collapse
Affiliation(s)
- Cecilia Marino
- Department of Child Neuropsychiatry, Scientific Institute Eugenio Medea, Bosisio Parini, Italy; Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Québec, Canada; Department of Psychiatry and Neuroscience, Université Laval, Québec, Canada
| | - Paola Scifo
- C.E.R.M.A.C. (Centro di Risonanza Magnetica ad Alto Campo), Milan, Italy; Department of Nuclear Medicine San Raffaele Hospital and Division of Neuroscience, Scientific Institute San Raffaele, Milan, Italy
| | - Pasquale A Della Rosa
- Institute of Molecular Bioimaging and Physiology, National Research Council, Milan, Italy
| | - Sara Mascheretti
- Department of Child Neuropsychiatry, Scientific Institute Eugenio Medea, Bosisio Parini, Italy
| | - Andrea Facoetti
- Department of Child Neuropsychiatry, Scientific Institute Eugenio Medea, Bosisio Parini, Italy; Department of General Psychology and Center for Cognitive Science, University of Padova, Padova, Italy
| | - Maria L Lorusso
- Department of Child Neuropsychiatry, Scientific Institute Eugenio Medea, Bosisio Parini, Italy
| | - Roberto Giorda
- Molecular Biology Laboratory, Scientific Institute Eugenio Medea, Bosisio Parini, Italy
| | - Monica Consonni
- Department of Nuclear Medicine San Raffaele Hospital and Division of Neuroscience, Scientific Institute San Raffaele, Milan, Italy
| | - Andrea Falini
- C.E.R.M.A.C. (Centro di Risonanza Magnetica ad Alto Campo), Milan, Italy
| | - Massimo Molteni
- Department of Child Neuropsychiatry, Scientific Institute Eugenio Medea, Bosisio Parini, Italy
| | - Jeffrey R Gruen
- Department of Pediatrics & Genetics, Yale Child Health Research Center, Yale School of Medicine, New Haven, USA
| | - Daniela Perani
- C.E.R.M.A.C. (Centro di Risonanza Magnetica ad Alto Campo), Milan, Italy; Department of Nuclear Medicine San Raffaele Hospital and Division of Neuroscience, Scientific Institute San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
| |
Collapse
|
33
|
Eicher JD, Gruen JR. Imaging-genetics in dyslexia: connecting risk genetic variants to brain neuroimaging and ultimately to reading impairments. Mol Genet Metab 2013; 110:201-12. [PMID: 23916419 PMCID: PMC3800223 DOI: 10.1016/j.ymgme.2013.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 12/19/2022]
Abstract
Dyslexia is a common pediatric disorder that affects 5-17% of schoolchildren in the United States. It is marked by unexpected difficulties in fluent reading despite adequate intelligence, opportunity, and instruction. Classically, neuropsychologists have studied dyslexia using a variety of neurocognitive batteries to gain insight into the specific deficits and impairments in affected children. Since dyslexia is a complex genetic trait with high heritability, analyses conditioned on performance on these neurocognitive batteries have been used to try to identify associated genes. This has led to some successes in identifying contributing genes, although much of the heritability remains unexplained. Additionally, the lack of relevant human brain tissue for analysis and the challenges of modeling a uniquely human trait in animals are barriers to advancing our knowledge of the underlying pathophysiology. In vivo imaging technologies, however, present new opportunities to examine dyslexia and reading skills in a clearly relevant context in human subjects. Recent investigations have started to integrate these imaging data with genetic data in attempts to gain a more complete and complex understanding of reading processes. In addition to bridging the gap from genetic risk variant to a discernible neuroimaging phenotype and ultimately to the clinical impairments in reading performance, the use of neuroimaging phenotypes will reveal novel risk genes and variants. In this article, we briefly discuss the genetic and imaging investigations and take an in-depth look at the recent imaging-genetics investigations of dyslexia.
Collapse
Affiliation(s)
- John D. Eicher
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520
| | - Jeffrey R. Gruen
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520
- Departments of Pediatrics and Investigative Medicine, Yale University School of Medicine, New Haven, CT 06520
| |
Collapse
|
34
|
Atherton J, Houdusse A, Moores C. MAPping out distribution routes for kinesin couriers. Biol Cell 2013; 105:465-87. [PMID: 23796124 DOI: 10.1111/boc.201300012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/17/2013] [Indexed: 12/14/2022]
Abstract
In the crowded environment of eukaryotic cells, diffusion is an inefficient distribution mechanism for cellular components. Long-distance active transport is required and is performed by molecular motors including kinesins. Furthermore, in highly polarised, compartmentalised and plastic cells such as neurons, regulatory mechanisms are required to ensure appropriate spatio-temporal delivery of neuronal components. The kinesin machinery has diversified into a large number of kinesin motor proteins as well as adaptor proteins that are associated with subsets of cargo. However, many mechanisms contribute to the correct delivery of these cargos to their target domains. One mechanism is through motor recognition of sub-domain-specific microtubule (MT) tracks, sign-posted by different tubulin isoforms, tubulin post-translational modifications, tubulin GTPase activity and MT-associated proteins (MAPs). With neurons as a model system, a critical review of these regulatory mechanisms is presented here, with a particular focus on the emerging contribution of compartmentalised MAPs. Overall, we conclude that - especially for axonal cargo - alterations to the MT track can influence transport, although in vivo, it is likely that multiple track-based effects act synergistically to ensure accurate cargo distribution.
Collapse
Affiliation(s)
- Joseph Atherton
- Institute of Structural and Molecular Biology, Birkbeck College, London, WC1E 7HX, UK
| | | | | |
Collapse
|
35
|
Platt MP, Adler WT, Mehlhorn AJ, Johnson GC, Wright KA, Choi RT, Tsang WH, Poon MW, Yeung SY, Waye MMY, Galaburda AM, Rosen GD. Embryonic disruption of the candidate dyslexia susceptibility gene homolog Kiaa0319-like results in neuronal migration disorders. Neuroscience 2013; 248:585-93. [PMID: 23831424 DOI: 10.1016/j.neuroscience.2013.06.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 02/04/2023]
Abstract
Developmental dyslexia, the most common childhood learning disorder, is highly heritable, and recent studies have identified KIAA0319-Like (KIAA0319L) as a candidate dyslexia susceptibility gene at the 1p36-34 (DYX8) locus. In this experiment, we investigated the anatomical effects of knocking down this gene during rat corticogenesis. Cortical progenitor cells were transfected using in utero electroporation on embryonic day (E) 15.5 with plasmids encoding either: (1) Kiaa0319l small hairpin RNA (shRNA), (2) an expression construct for human KIAA0319L, (3) Kiaa0319l shRNA+KIAA0319L expression construct (rescue), or (4) controls (scrambled Kiaa0319l shRNA or empty expression vector). Mothers were injected with 5-bromo-2-deoxyuridine (BrdU) at either E13.5, E15.5, or E17.5. Disruption of Kiaa0319l function (by knockdown, overexpression, or rescue) resulted in the formation of large nodular periventricular heterotopia in approximately 25% of the rats, which can be seen as early as postnatal day 1. Only a small subset of heterotopic neurons had been transfected, indicating non-cell autonomous effects of the transfection. Most heterotopic neurons were generated in mid- to late-gestation, and laminar markers suggest that they were destined for upper cortical laminae. Finally, we found that transfected neurons in the cerebral cortex were located in their expected laminae. These results indicate that KIAA0319L is the fourth of four candidate dyslexia susceptibility genes that is involved in neuronal migration, which supports the association of abnormal neuronal migration with developmental dyslexia.
Collapse
Affiliation(s)
- M P Platt
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - W T Adler
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - A J Mehlhorn
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - G C Johnson
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - K A Wright
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - R T Choi
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - W H Tsang
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - M W Poon
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - S Y Yeung
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - M M Y Waye
- School of Biomedical Sciences & School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - A M Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - G D Rosen
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
| |
Collapse
|
36
|
Adler WT, Platt MP, Mehlhorn AJ, Haight JL, Currier TA, Etchegaray MA, Galaburda AM, Rosen GD. Position of neocortical neurons transfected at different gestational ages with shRNA targeted against candidate dyslexia susceptibility genes. PLoS One 2013; 8:e65179. [PMID: 23724130 PMCID: PMC3665803 DOI: 10.1371/journal.pone.0065179] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/24/2013] [Indexed: 01/12/2023] Open
Abstract
Developmental dyslexia is a language learning disorder that affects approximately 4–10% of the population. A number of candidate dyslexia susceptibility genes have been identified, including DCDC2 and KIAA0319 on Chromosome (Chr) 6p22.2 and DYX1C1 on Chr 15q21. Embryonic knockdown of the function of homologs of these genes in rat neocortical projection cell progenitors by in utero electroporation of plasmids encoding small hairpin RNA (shRNA) revealed that all three genes disrupted neuronal migration to the neocortex. Specifically, this disruption would result in heterotopia formation (Dyx1c1 and Kiaa0319) and/or overmigration past their expected laminar location (Dyx1c1 and Dcdc2). In these experiments, neurons normally destined for the upper neocortical laminæ were transfected on embryonic day (E) 15.5, and we designed experiments to test whether these migration phenotypes were the result of targeting a specific type of projection neuron. We transfected litters with Dcdc2 shRNA, Dyx1c1 shRNA, Kiaa0319 shRNA, or fluorescent protein (as a control) at each of three gestational ages (E14.5, E15.5, or E16.5). Pups were allowed to come to term, and their brains were examined at 3 weeks of age for the position of transfected cells. We found that age of transfection did not affect the percentage of unmigrated neurons—transfection with Kiaa0319 shRNA resulted in heterotopia formation at all three ages. Overmigration of neurons transfected with Dcdc2 shRNA, while present following transfections at the later ages, did not occur following E14.5 transfections. These results are considered in light of the known functions of each of these candidate dyslexia susceptibility genes.
Collapse
Affiliation(s)
- William T. Adler
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Maryann P. Platt
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Alison J. Mehlhorn
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Joshua L. Haight
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Timothy A. Currier
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Mikel A. Etchegaray
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Albert M. Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Glenn D. Rosen
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
37
|
The zebrafish orthologue of the dyslexia candidate gene DYX1C1 is essential for cilia growth and function. PLoS One 2013; 8:e63123. [PMID: 23650548 PMCID: PMC3641089 DOI: 10.1371/journal.pone.0063123] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/28/2013] [Indexed: 11/19/2022] Open
Abstract
DYX1C1, a susceptibility gene for dyslexia, encodes a tetratricopeptide repeat domain containing protein that has been implicated in neuronal migration in rodent models. The developmental role of this gene remains unexplored. To understand the biological function(s) of zebrafish dyx1c1 during embryonic development, we cloned the zebrafish dyx1c1 and used morpholino-based knockdown strategy. Quantitative real-time PCR analysis revealed the presence of dyx1c1 transcripts in embryos, early larval stages and in a wide range of adult tissues. Using mRNA in situ hybridization, we show here that dyx1c1 is expressed in many ciliated tissues in zebrafish. Inhibition of dyx1c1 produced pleiotropic phenotypes characteristically associated with cilia defects such as body curvature, hydrocephalus, situs inversus and kidney cysts. We also demonstrate that in dyx1c1 morphants, cilia length is reduced in several organs including Kupffer’s vesicle, pronephros, spinal canal and olfactory placode. Furthermore, electron microscopic analysis of cilia in dyx1c1 morphants revealed loss of both outer (ODA) and inner dynein arms (IDA) that have been shown to be required for cilia motility. Considering all these results, we propose an essential role for dyx1c1 in cilia growth and function.
Collapse
|
38
|
Szalkowski CE, Fiondella CF, Truong DT, Rosen GD, LoTurco JJ, Fitch RH. The effects of Kiaa0319 knockdown on cortical and subcortical anatomy in male rats. Int J Dev Neurosci 2013; 31:116-22. [PMID: 23220223 PMCID: PMC3689304 DOI: 10.1016/j.ijdevneu.2012.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 12/13/2022] Open
Abstract
Developmental dyslexia is a disorder characterized by a specific deficit in reading despite adequate overall intelligence and educational resources. The neurological substrate underlying these significant behavioral impairments is not known. Studies of post mortem brain tissue from male and female dyslexic individuals revealed focal disruptions of neuronal migration concentrated in the left hemisphere, along with aberrant symmetry of the right and left the planum temporale, and changes in cell size distribution within the medial geniculate nucleus of the thalamus (Galaburda et al., 1985; Humphreys et al., 1990). More recent neuroimaging studies have identified several changes in the brains of dyslexic individuals, including regional changes in gray matter, changes in white matter, and changes in patterns of functional activation. In a further effort to elucidate the etiology of dyslexia, epidemiological and genetic studies have identified several candidate dyslexia susceptibility genes. Some recent work has investigated associations between some of these genetic variants and structural changes in the brain. Variants of one candidate dyslexia susceptibility gene, KIAA0319, have been linked to morphological changes in the cerebellum and functional activational changes in the superior temporal sulcus (Jamadar et al., 2011; Pinel et al., 2012). Animal models have been used to create a knockdown of Kiaa0319 (the rodent homolog of the human gene) via in utero RNA interference in order to study the gene's effects on brain development and behavior. Studies using this animal model have demonstrated that knocking down the gene leads to focal disruptions of neuronal migration in the form of ectopias and heterotopias, similar to those observed in the brains of human dyslexics. However, further changes to the structure of the brain have not been studied following this genetic disruption. The current study sought to determine the effects of embryonic Kiaa0319 knockdown on volume of the cortex and hippocampus, as well as midsagittal area of the corpus callosum in male rats. Results demonstrate that Kiaa0319 knockdown did not change the volume of the cortex or hippocampus, but did result in a significant reduction in the midsagittal area of the corpus callosum. Taken in the context of previous reports of behavioral deficits following Kiaa0319 knockdown (Szalkowski et al., 2012), and reports that reductions of corpus callosum size are related to processing deficits in humans (Paul, 2011), these results suggest that Kiaa0319 has a specific involvement in neural systems important for temporal processing.
Collapse
Affiliation(s)
- Caitlin E Szalkowski
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, Storrs, 06269, United States.
| | | | | | | | | | | |
Collapse
|
39
|
Centanni TM, Booker AB, Sloan AM, Chen F, Maher BJ, Carraway RS, Khodaparast N, Rennaker R, LoTurco JJ, Kilgard MP. Knockdown of the dyslexia-associated gene Kiaa0319 impairs temporal responses to speech stimuli in rat primary auditory cortex. Cereb Cortex 2013; 24:1753-66. [PMID: 23395846 DOI: 10.1093/cercor/bht028] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
One in 15 school age children have dyslexia, which is characterized by phoneme-processing problems and difficulty learning to read. Dyslexia is associated with mutations in the gene KIAA0319. It is not known whether reduced expression of KIAA0319 can degrade the brain's ability to process phonemes. In the current study, we used RNA interference (RNAi) to reduce expression of Kiaa0319 (the rat homolog of the human gene KIAA0319) and evaluate the effect in a rat model of phoneme discrimination. Speech discrimination thresholds in normal rats are nearly identical to human thresholds. We recorded multiunit neural responses to isolated speech sounds in primary auditory cortex (A1) of rats that received in utero RNAi of Kiaa0319. Reduced expression of Kiaa0319 increased the trial-by-trial variability of speech responses and reduced the neural discrimination ability of speech sounds. Intracellular recordings from affected neurons revealed that reduced expression of Kiaa0319 increased neural excitability and input resistance. These results provide the first evidence that decreased expression of the dyslexia-associated gene Kiaa0319 can alter cortical responses and impair phoneme processing in auditory cortex.
Collapse
Affiliation(s)
- T M Centanni
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| | | | - A M Sloan
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| | - F Chen
- University of Connecticut
| | | | - R S Carraway
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| | - N Khodaparast
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| | - R Rennaker
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| | | | - M P Kilgard
- School of Behavioral and Brain Sciences, University of Texas at Dallas
| |
Collapse
|
40
|
Raskind WH, Peter B, Richards T, Eckert MM, Berninger VW. The genetics of reading disabilities: from phenotypes to candidate genes. Front Psychol 2013; 3:601. [PMID: 23308072 PMCID: PMC3538356 DOI: 10.3389/fpsyg.2012.00601] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 12/18/2012] [Indexed: 12/19/2022] Open
Abstract
This article provides an overview of (a) issues in definition and diagnosis of specific reading disabilities at the behavioral level that may occur in different constellations of developmental and phenotypic profiles (patterns); (b) rapidly expanding research on genetic heterogeneity and gene candidates for dyslexia and other reading disabilities; (c) emerging research on gene-brain relationships; and (d) current understanding of epigenetic mechanisms whereby environmental events may alter behavioral expression of genetic variations. A glossary of genetic terms (denoted by bold font) is provided for readers not familiar with the technical terms.
Collapse
Affiliation(s)
- Wendy H Raskind
- Department of Medicine, University of Washington Seattle, WA, USA ; Department of Psychiatry and Behavioral Sciences, University of Washington Seattle, WA, USA
| | | | | | | | | |
Collapse
|
41
|
Meta-analysis of the Association Between DCDC2 Polymorphisms and Risk of Dyslexia. Mol Neurobiol 2012; 47:435-42. [DOI: 10.1007/s12035-012-8381-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
|
42
|
Han X, Fang X, Lou X, Hua D, Ding W, Foltz G, Hood L, Yuan Y, Lin B. Silencing SOX2 induced mesenchymal-epithelial transition and its expression predicts liver and lymph node metastasis of CRC patients. PLoS One 2012; 7:e41335. [PMID: 22912670 PMCID: PMC3422347 DOI: 10.1371/journal.pone.0041335] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 06/25/2012] [Indexed: 12/15/2022] Open
Abstract
SOX2 is an important stem cell marker and plays important roles in development and carcinogenesis. However, the role of SOX2 in Epithelial-Mesenchymal Transition has not been investigated. We demonstrated, for the first time, that SOX2 is involved in the Epithelial-Mesenchymal Transition (EMT) process as knock downof SOX2 in colorectal cancer (CRC) SW620 cells induced a Mesenchymal-Epithelial Transition (MET) process with recognized changes in the expression of key genes involved in the EMT process including E-cadherin and vimentin. In addition, we provided a link between SOX2 activity and the WNT pathway by showing that knock down of SOX2 reduced the WNT pathway activity in colorectal cancer (CRC) cells. We further demonstrated that SOX2 is involved in cell migration and invasion in vitro and in metastasis in vivo for CRC cells, and that the process might be mediated through the MMP2 activity. Finally, an IHC analysis of 44 cases of colorectal cancer patients suggested that SOX2 is a prognosis marker for metastasis of colorectal cancers.
Collapse
Affiliation(s)
- Xu Han
- Systems Biology Division, Zhejiang–California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xuefeng Fang
- Department of Medical Oncology, The 2nd Hospital of Zhejiang University Medical College, Hangzhou, Zhejiang, China
| | - Xiaoyan Lou
- Systems Biology Division, Zhejiang–California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Dasong Hua
- Systems Biology Division, Zhejiang–California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenchao Ding
- Systems Biology Division, Zhejiang–California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Gregory Foltz
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, United States of America
| | - Leroy Hood
- The Institute for Systems Biology, Seattle, Washington, United States of America
| | - Ying Yuan
- Department of Medical Oncology, The 2nd Hospital of Zhejiang University Medical College, Hangzhou, Zhejiang, China
- * E-mail: (YY); (BL)
| | - Biaoyang Lin
- Systems Biology Division, Zhejiang–California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, China
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, United States of America
- Department of Urology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (YY); (BL)
| |
Collapse
|
43
|
Abstract
OBJECTIVE(S) Developmental dyslexia is a heritable condition, with genetic factors accounting for 44-75% of the variance in performance tests of reading component subphenotypes. Compelling genetic linkage and association evidence supports a quantitative trait locus in the 6p21.3 region that encodes a gene called DCDC2. In this study, we explored the contribution of two DCDC2 markers to dyslexia, related reading and memory phenotypes in nuclear families of Italian origin. METHODS The 303 nuclear families recruited on the basis of having a proband with developmental dyslexia have been studied with 6p21.3 markers, BV677278 and rs793862. Marker-trait association was investigated by the quantitative transmission disequilibrium test (version 2.5.1) that allows for the analyses of quantitative traits. Seven phenotypes were used in association analyses, that is, word and nonword reading, word and nonword spelling, orthographic choice, memory, and the affected status based on inclusion criteria. RESULTS Quantitative transmission disequilibrium test analyses yielded evidence for association between reading skills and the BV677278 deletion (empirical P-values=0.025-0.029) and between memory and BV677278 allele 10 (empirical P-value=0.0001). CONCLUSION Our result adds further evidence in support of DCDC2 contributing to the deficits in developmental dyslexia. More specifically, our data support the view that DCDC2 influences both reading and memory impairments thus shedding further light into the etiologic basis and the phenotypic complexity of developmental dyslexia.
Collapse
|
44
|
Aberrant expression of the neuronal-specific protein DCDC2 promotes malignant phenotypes and is associated with prostate cancer progression. Oncogene 2012; 32:2315-24, 2324.e1-4. [PMID: 22733135 DOI: 10.1038/onc.2012.245] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
By integrating gene profiling and immunohistochemical data with functional experiments in cell lines in this study we show for the first time that doublecortin (DCX) domain containing 2 (DCDC2), a protein belonging to the DCX family and involved in neuronal cell migration, is aberrantly expressed in prostate tumors whereas absent in normal prostate. Furthermore, in patients treated with radical prostatectomy, high levels of DCDC2 RNA were significantly associated with increased biochemical relapse (LogRank Mantel-Cox=0.012). Mechanistically, we found that the ETS transcription factor ESE3/EHF, which is expressed in normal prostate and frequently lost in prostate tumors, maintained DCDC2 repressed by binding to a novel identified ETS binding site in the gene promoter. Consistently, in prostate tumors and in cellular models of gain and loss of ESE3/EHF, the expression of DCDC2 and ESE3/EHF were inversely correlated. In prostate cancer cells, DCDC2 colocalized with microtubules and promoted cell migration and resistance to the microtubule-targeting drug taxol. Collectively, this study establishes DCDC2 as a novel ESE3/EHF oncogenic target in prostate cancer. These findings may be relevant for the clinical management of prostate cancer as DCDC2 may signal tumors more prone to relapse and resistant to taxol treatment.
Collapse
|
45
|
Szalkowski CE, Fiondella CG, Galaburda AM, Rosen GD, Loturco JJ, Fitch RH. Neocortical disruption and behavioral impairments in rats following in utero RNAi of candidate dyslexia risk gene Kiaa0319. Int J Dev Neurosci 2012; 30:293-302. [PMID: 22326444 PMCID: PMC3516384 DOI: 10.1016/j.ijdevneu.2012.01.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 11/22/2022] Open
Abstract
Within the last decade several genes have been identified as candidate risk genes for developmental dyslexia. Recent research using animal models and embryonic RNA interference (RNAi) has shown that a subset of the candidate dyslexia risk genes--DYX1C1, ROBO1, DCDC2, KIAA0319--regulate critical parameters of neocortical development, such as neuronal migration. For example, embryonic disruption of the rodent homolog of DYX1C1 disrupts neuronal migration and produces deficits in rapid auditory processing (RAP) and working memory--phenotypes that have been reported to be associated with developmental dyslexia. In the current study we used a modified prepulse inhibition paradigm to assess acoustic discrimination abilities of male Wistar rats following in utero RNA interference targeting Kiaa0319. We also assessed spatial learning and working memory using a Morris water maze (MWM) and a radial arm water maze. We found that embryonic interference with this gene resulted in disrupted migration of neocortical neurons leading to formation of heterotopia in white matter, and to formation of hippocampal dysplasia in a subset of animals. These animals displayed deficits in processing complex acoustic stimuli, and those with hippocampal malformations exhibited impaired spatial learning abilities. No significant impairment in working memory was detected in the Kiaa0319 RNAi treated animals. Taken together, these results suggest that Kiaa0319 plays a role in neuronal migration during embryonic development, and that early interference with this gene results in an array of behavioral deficits including impairments in rapid auditory processing and simple spatial learning.
Collapse
Affiliation(s)
- Caitlin E Szalkowski
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, USA.
| | | | | | | | | | | |
Collapse
|
46
|
Gabel LA, Marin I, LoTurco JJ, Che A, Murphy C, Manglani M, Kass S. Mutation of the dyslexia-associated gene Dcdc2 impairs LTM and visuo-spatial performance in mice. GENES BRAIN AND BEHAVIOR 2011; 10:868-75. [PMID: 21883923 DOI: 10.1111/j.1601-183x.2011.00727.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Developmental reading disorder (RD) affects 5-10% of school aged children, with a heritability of approximately 60%. Genetic association studies have identified several candidate RD susceptibility genes, including DCDC2; however, a direct connection between the function of these genes and cognitive or learning impairments remains unclear. Variants in DCDC2, a member of the doublecortin family of genes, have been associated in humans with RD and ADHD and Dcdc2 may play a role in neuronal migration in rats. In this study, we examined the effect of Dcdc2 mutation on cognitive abilities in mice using a visual attention and visuo-spatial learning and memory task. We show that both heterozygous and homozygous mutations of Dcdc2 result in persistent visuo-spatial memory deficits, as well as visual discrimination and long-term memory deficits. These behavioral deficits occur in the absence of neuronal migration disruption in the mutant mice, and may be comorbid with an anxiety phenotype. These are the first results to suggest a direct relationship between induced mutation in Dcdc2 and changes in behavioral measures. Dcdc2 mutant mice should prove useful in future studies designed to further dissect the underlying neural mechanisms that are impaired following Dcdc2 mutation.
Collapse
Affiliation(s)
- L A Gabel
- Department of Psychology, Lafayette College, Easton, PA 18042, USA.
| | | | | | | | | | | | | |
Collapse
|
47
|
Li W, Wu ZQ, Zhao J, Guo SJ, Li Z, Feng X, Ma L, Zhang JS, Liu XP, Zhang YQ. Transient protection from heat-stress induced apoptotic stimulation by metastasis-associated protein 1 in pachytene spermatocytes. PLoS One 2011; 6:e26013. [PMID: 22022494 PMCID: PMC3192157 DOI: 10.1371/journal.pone.0026013] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/15/2011] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Deregulated thermal factors have been frequently implicated in the pathogenesis of male infertility, but the molecular basis through which certain responses are directed remain largely unknown. We previously reported that overexpression of exogenous Metastasis-associated protein 1 (MTA1) protects spermatogenic tumor cells GC-2spd (ts) against heat-induced apoptosis. To further dissect the underlying mechanism, we addressed here the fine coordination between MTA1 and p53 in pachytene spermatocytes upon hyperthermal stimulation. METHODOLOGY/PRINCIPAL FINDINGS High level of MTA1 expression sustained for 1.5 h in primary spermatocytes after heat stress before a notable decrease was detected conversely correlated to the gradual increase of acetylation status of p53 and of p21 level. Knockdown of the endogenous MTA1 in GC-2spd (ts) elevated the acetylation of p53 by diminishing the recruitment of HDAC2 and thereafter led to a dramatic increase of apoptosis after heat treatment. Consistent with this, in vivo interference of MTA1 expression in the testes of C57BL/6 mice also urged an impairment of the differentiation of spermatocytes and a disruption of Sertoli cell function due to the elevated apoptotic rate after heat stress. Finally, attenuated expression of MTA1 of pachytene spermatocytes was observed in arrested testes (at the round spermatid level) of human varicocele patients. CONCLUSIONS These data underscore a transient protective effect of this histone modifier in primary spermatocytes against heat-stress, which may operate as a negative coregulator of p53 in maintenance of apoptotic balance during early phase after hyperthermal stress.
Collapse
Affiliation(s)
- Wei Li
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Zhi-qun Wu
- Department of Interventional Radiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Jie Zhao
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Sheng-jie Guo
- Department of Urology, Cancer Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Zhen Li
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Xiao Feng
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Li Ma
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Jin-shan Zhang
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Xin-ping Liu
- Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Yuan-qiang Zhang
- Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi'an, People's Republic of China
| |
Collapse
|
48
|
Massinen S, Hokkanen ME, Matsson H, Tammimies K, Tapia-Páez I, Dahlström-Heuser V, Kuja-Panula J, Burghoorn J, Jeppsson KE, Swoboda P, Peyrard-Janvid M, Toftgård R, Castrén E, Kere J. Increased expression of the dyslexia candidate gene DCDC2 affects length and signaling of primary cilia in neurons. PLoS One 2011; 6:e20580. [PMID: 21698230 PMCID: PMC3116825 DOI: 10.1371/journal.pone.0020580] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 05/04/2011] [Indexed: 12/14/2022] Open
Abstract
DCDC2 is one of the candidate susceptibility genes for dyslexia. It belongs to the superfamily of doublecortin domain containing proteins that bind to microtubules, and it has been shown to be involved in neuronal migration. We show that the Dcdc2 protein localizes to the primary cilium in primary rat hippocampal neurons and that it can be found within close proximity to the ciliary kinesin-2 subunit Kif3a. Overexpression of DCDC2 increases ciliary length and activates Shh signaling, whereas downregulation of Dcdc2 expression enhances Wnt signaling, consistent with a functional role in ciliary signaling. Moreover, DCDC2 overexpression in C. elegans causes an abnormal neuronal phenotype that can only be seen in ciliated neurons. Together our results suggest a potential role for DCDC2 in the structure and function of primary cilia.
Collapse
Affiliation(s)
- Satu Massinen
- Research Program's Unit, Molecular Medicine and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | | | - Hans Matsson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Kristiina Tammimies
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Isabel Tapia-Páez
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | | | - Jan Burghoorn
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- School of Life Sciences, Södertörn University College, Huddinge, Sweden
| | - Kristian E. Jeppsson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- School of Life Sciences, Södertörn University College, Huddinge, Sweden
| | - Peter Swoboda
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- School of Life Sciences, Södertörn University College, Huddinge, Sweden
| | | | - Rune Toftgård
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Eero Castrén
- Neuroscience Center, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Juha Kere
- Research Program's Unit, Molecular Medicine and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Neuroscience Center, University of Helsinki, Helsinki, Finland
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- Folkhälsan Institute of Genetics, Helsinki, Finland
| |
Collapse
|
49
|
Wang Y, Yin X, Rosen G, Gabel L, Guadiana SM, Sarkisian MR, Galaburda AM, Loturco JJ. Dcdc2 knockout mice display exacerbated developmental disruptions following knockdown of doublecortin. Neuroscience 2011; 190:398-408. [PMID: 21689730 DOI: 10.1016/j.neuroscience.2011.06.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 05/27/2011] [Accepted: 06/01/2011] [Indexed: 12/12/2022]
Abstract
The dyslexia-associated gene DCDC2 is a member of the DCX family of genes known to play roles in neurogenesis, neuronal migration, and differentiation. Here we report the first phenotypic analysis of a Dcdc2 knockout mouse. Comparisons between Dcdc2 knockout mice and wild-type (wt) littermates revealed no significant differences in neuronal migration, neocortical lamination, neuronal cilliogenesis or dendritic differentiation. Considering previous studies showing genetic interactions and potential functional redundancy among members of the DCX family, we tested whether decreasing Dcx expression by RNAi would differentially impair neurodevelopment in Dcdc2 knockouts and wild-type mice. Consistent with this hypothesis, we found that deficits in neuronal migration, and dendritic growth caused by RNAi of Dcx were more severe in Dcdc2 knockouts than in wild-type mice with the same transfection. These results indicate that Dcdc2 is not required for neurogenesis, neuronal migration or differentiation in mice, but may have partial functional redundancy with Dcx.
Collapse
Affiliation(s)
- Y Wang
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Poelmans G, Buitelaar JK, Pauls DL, Franke B. A theoretical molecular network for dyslexia: integrating available genetic findings. Mol Psychiatry 2011; 16:365-82. [PMID: 20956978 DOI: 10.1038/mp.2010.105] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Developmental dyslexia is a common specific childhood learning disorder with a strong heritable component. Previous studies using different genetic approaches have identified several genetic loci and candidate genes for dyslexia. In this article, we have integrated the current knowledge on 14 dyslexia candidate genes suggested by cytogenetic findings, linkage and association studies. We found that 10 of the 14 dyslexia candidate genes (ROBO1, KIAA0319, KIAA0319L, S100B, DOCK4, FMR1, DIP2A, GTF2I, DYX1C1 and DCDC2) fit into a theoretical molecular network involved in neuronal migration and neurite outgrowth. Based on this, we also propose three novel dyslexia candidate genes (SLIT2, HMGB1 and VAPA) from known linkage regions, and we discuss the possible involvement of genes emerging from the two reported genome-wide association studies for reading impairment-related phenotypes in the identified network.
Collapse
Affiliation(s)
- G Poelmans
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | | | |
Collapse
|