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Boucher AN, Bhat BH, Clemens NH, Vaughn S, O'Donnell K. Reading Interventions for Students in Grades 3-12 With Significant Word Reading Difficulties. JOURNAL OF LEARNING DISABILITIES 2024; 57:203-223. [PMID: 37937699 DOI: 10.1177/00222194231207556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Most students with reading difficulties struggle to read words. We examined intervention effects for students with significant word reading difficulties (SWRD; standard score of 80 on at least one pretest measure of word reading), which includes individuals with or at risk for dyslexia. We investigated: (a) What are the effects of reading interventions for students in Grades 3-12 with SWRD? and (b) What intervention features (i.e., instructional components and elements of dosage) are related to improved reading outcomes for the target population? A meta-analysis of 22 studies and 208 effect sizes revealed a statistically significant, positive, mean effect (g = 0.14, standard error [SE] = 0.04, p = .01, 95% confidence interval [CI]: [0.04, 0.23]) of interventions for the target population. Subset analyses revealed positive, statistically significant intervention effects on measures of pseudoword reading (g = 0.38, SE = 0.07, p = .0003, 95% CI [0.21, 0.54]) and pseudoword reading fluency (g = 0.29, SE = 0.09, p = .010, 95% CI [0.09, 0.49]). Moderator analyses yielded statistically significant, positive effects associated with increased total hours of intervention, β = 0.003, SE = 0.0009, t(8.31) = 3.58, p = .007. Overall, findings indicate a need for interventions that improve generalized real-world reading for the target population.
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Shao S, Niu Y, Zhang X, Kong R, Wang J, Liu L, Luo X, Zhang J, Song R. Opposite Associations between Individual KIAA0319 Polymorphisms and Developmental Dyslexia Risk across Populations: A Stratified Meta-Analysis by the Study Population. Sci Rep 2016; 6:30454. [PMID: 27464509 PMCID: PMC4964335 DOI: 10.1038/srep30454] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 07/06/2016] [Indexed: 02/08/2023] Open
Abstract
KIAA0319 at the DYX2 locus is one of the most extensively studied candidate genes for developmental dyslexia (DD) owing to its important role in neuronal migration. Previous research on associations between KIAA0319 genetic variations and DD has yielded inconsistent results. It is important to establish a more precise estimate of the DD risk associated with these genetic variations. We carried out a meta-analysis of association studies involving KIAA0319 polymorphisms and DD risk. The results of pooled analysis indicated that none of the six investigated markers in or near the KIAA0319 gene are associated with DD. However, a stratified analysis by the study population revealed opposite associations involving KIAA0319 rs4504469 in European and Asian subgroups. The stratified analysis also showed that the KIAA0319 rs9461045 minor allele (T allele) has a protective effect in Asians. This meta-analysis has allowed us to establish the effects of specific KIAA0319 polymorphisms on DD risk with greater precision, as they vary across populations; analyzing one single nucleotide polymorphism at a time could not fully explain the genetic association for DD.
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Affiliation(s)
- Shanshan Shao
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yanfeng Niu
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xiaohui Zhang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Rui Kong
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia Wang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lingfei Liu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiu Luo
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jiajia Zhang
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, 29208, USA
| | - Ranran Song
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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Vagge A, Cavanna M, Traverso CE, Iester M. Evaluation of ocular movements in patients with dyslexia. ANNALS OF DYSLEXIA 2015; 65:24-32. [PMID: 25804764 DOI: 10.1007/s11881-015-0098-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/04/2015] [Indexed: 05/21/2023]
Abstract
The aims of this study were to analyze the relationship between dyslexia and eye movements and to assess whether this method can be added to the workup of dyslexic patients. The sample was comprised of 11 children with a diagnosis of dyslexia and 11 normal between 8 and 13 years of age. All subjects underwent orthoptic evaluation, ophthalmological examinations, and eye movement analysis, specifically, stability analysis on fixating a still target, tracking saccades, analysis of fixation pauses, speed reading, saccades, and regressions through the reading of a text. Stability analysis on fixating a still target showed a significant (p < 0.001) difference between the two groups showing an increased amount of loss of fixation among dyslexic subjects (5.36 ± 2.5 s and 0.82 ± 2.1, respectively). Tracking saccades (left and right horizontal axis) did not show a significant difference. When reading parameters were looked into (number of saccades, number of regressions, reading time through the reading of a text), a significant (p < 0.001) difference was found between the groups. This study supports the belief that the alteration of eye movement does not depend on oculo-motor dysfunction but is secondary to a defect in the visual processing of linguistic material. Inclusion of assessment of this defect might prove beneficial in determining the presence of dyslexia in young children at a younger age, and an earlier intervention could be initiated.
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Affiliation(s)
- Aldo Vagge
- Clinica Oculistica, DiNOGMI, University of Genoa, Viale Benedetto XV 5, 16132, Genoa, Italy
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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.
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Veerappa AM, Saldanha M, Padakannaya P, Ramachandra NB. Family based genome-wide copy number scan identifies complex rearrangements at 17q21.31 in dyslexics. Am J Med Genet B Neuropsychiatr Genet 2014; 165B:572-80. [PMID: 25139666 DOI: 10.1002/ajmg.b.32260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/26/2014] [Indexed: 01/18/2023]
Abstract
Developmental dyslexia (DD) is a complex heritable disorder with unexpected difficulty in learning to read and spell despite adequate intelligence, education, environment, and normal senses. We performed genome-wide screening for copy number variations (CNVs) in 10 large Indian dyslexic families using Affymetrix Genome-Wide Human SNP Array 6.0. Results revealed the complex genomic rearrangements due to one non-contiguous deletion and five contiguous micro duplications and micro deletions at 17q21.31 region in three dyslexic families. CNVs in this region harbor the genes KIAA1267, LRRC37A, ARL17A/B, NSFP1, and NSF. The CNVs in case 1 and case 2 at this locus were found to be in homozygous state and case 3 was a de novo CNV. These CNVs were found with at least one CNV having a common break and end points in the parents. This cluster of genes containing NSF is implicated in learning, cognition, and memory, though not formally associated with dyslexia. Molecular network analysis of these and other dyslexia related module genes suggests NSF and other genes to be associated with cellular/vesicular membrane fusion and synaptic transmission. Thus, we suggest that NSF in this cluster would be the nearest gene responsible for the learning disability phenotype.
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Affiliation(s)
- Avinash M Veerappa
- Genetics and Genomics Laboratory, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore
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Kraft SJ, DeThorne LS. The Brave New World of Epigenetics: Embracing Complexity in the Study of Speech and Language Disorders. CURRENT DEVELOPMENTAL DISORDERS REPORTS 2014. [DOI: 10.1007/s40474-014-0024-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Veerappa AM, Saldanha M, Padakannaya P, Ramachandra NB. Family-based genome-wide copy number scan identifies five new genes of dyslexia involved in dendritic spinal plasticity. J Hum Genet 2013; 58:539-47. [PMID: 23677055 DOI: 10.1038/jhg.2013.47] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 01/21/2023]
Abstract
Genome-wide screening for copy number variations (CNVs) in ten Indian dyslexic families revealed the presence of five de novo CNVs in regions harboring GABARAP, NEGR1, ACCN1, DCDC5, and one in already known candidate gene CNTNAP2. These genes are located on regions of chromosomes 17p13.1, 1p31.1, 17q11.21, 11p14.1 and 7q35, respectively, and are implicated in learning, cognition and memory processes through dendritic spinal plasticity, though not formally associated with dyslexia. Molecular network analysis of these and other dyslexia-related module genes suggests them to be associated with synaptic transmission, axon guidance and cell adhesion. Thus, we suggest that dyslexia may also be caused by neuronal disconnection in addition to the earlier view that it is due to neuronal migrational disorder.
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Affiliation(s)
- Avinash M Veerappa
- Genomics Laboratory, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, India
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Analysis of genetic variants of dyslexia candidate genes KIAA0319 and DCDC2 in Indian population. J Hum Genet 2013; 58:531-8. [PMID: 23677054 DOI: 10.1038/jhg.2013.46] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 11/08/2022]
Abstract
Developmental dyslexia (DD) is a heritable, complex genetic disorder associated with impairment in reading and writing skills despite having normal intellectual ability and appropriate educational opportunities. Chromosome 6p23-21.3 at DYX2 locus has showed the most consistent evidence of linkage for DD and two susceptible genes KIAA0319 and DCDC2 for DD at DYX2 locus showed significant association. Specific candidate gene-association studies have identified variants, risk haplotypes and microsatellites of KIAA0319 and DCDC2 correlated with wide range of reading-related traits. In this study, we used a case-control approach for analyzing single-nucleotide polymorphisms (SNPs) in KIAA0319 and DCDC2. Our study demonstrated the association of DD with SNP rs4504469 of KIAA0319 and not with any SNPs of DCDC2.
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Peter B, Matsushita M, Raskind WH. Motor sequencing deficit as an endophenotype of speech sound disorder: a genome-wide linkage analysis in a multigenerational family. Psychiatr Genet 2013; 22:226-34. [PMID: 22517379 DOI: 10.1097/ypg.0b013e328353ae92] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVES The aim of this pilot study was to investigate a measure of motor sequencing deficit as a potential endophenotype of speech sound disorder (SSD) in a multigenerational family with evidence of familial SSD. METHODS In a multigenerational family with evidence of a familial motor-based SSD, affectation status and a measure of motor sequencing during oral motor testing were obtained. To further investigate the role of motor sequencing as an endophenotype for genetic studies, parametric and nonparametric linkage analyses were carried out using a genome-wide panel of 404 microsatellites. RESULTS In seven of the 10 family members with available data, SSD affectation status and motor sequencing status coincided. Linkage analysis revealed four regions of interest, 6p21, 7q32, 7q36, and 8q24, primarily identified with the measure of motor sequencing ability. The 6p21 region overlaps with a locus implicated in rapid alternating naming in a recent genome-wide dyslexia linkage study. The 7q32 locus contains a locus implicated in dyslexia. The 7q36 locus borders on a gene known to affect the component traits of language impairment. CONCLUSION The results are consistent with a motor-based endophenotype of SSD that would be informative for genetic studies. The linkage results in this first genome-wide study in a multigenerational family with SSD warrant follow-up in additional families and with fine mapping or next-generation approaches to gene identification.
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Affiliation(s)
- Beate Peter
- Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98195, USA.
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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.
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Lewis BA, Avrich AA, Freebairn LA, Hansen AJ, Sucheston LE, Kuo I, Taylor HG, Iyengar SK, Stein CM. Literacy outcomes of children with early childhood speech sound disorders: impact of endophenotypes. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2011; 54:1628-43. [PMID: 21930616 PMCID: PMC3404457 DOI: 10.1044/1092-4388(2011/10-0124)] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
PURPOSE To demonstrate that early childhood speech sound disorders (SSD) and later school-age reading, written expression, and spelling skills are influenced by shared endophenotypes that may be in part genetic. METHOD Children with SSD and their siblings were assessed at early childhood (ages 4-6 years) and followed at school age (7-12 years). The relationship of shared endophenotypes with early childhood SSD and school-age outcomes and the shared genetic influences on these outcomes were examined. RESULTS Structural equation modeling demonstrated that oral motor skills, phonological awareness, phonological memory, vocabulary, and speeded naming have varying influences on reading decoding, spelling, spoken language, and written expression at school age. Genetic linkage studies demonstrated linkage for reading, spelling, and written expression measures to regions on chromosomes 1, 3, 6, and 15 that were previously linked to oral motor skills, articulation, phonological memory, and vocabulary at early childhood testing. CONCLUSIONS Endophenotypes predict school-age literacy outcomes over and above that predicted by clinical diagnoses of SSD or language impairment. Findings suggest that these shared endophenotypes and common genetic influences affect early childhood SSD and later school-age reading, spelling, spoken language, and written expression skills.
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Li C, Sun SY, Khuri FR, Li R. Pleiotropic functions of EAPII/TTRAP/TDP2: cancer development, chemoresistance and beyond. Cell Cycle 2011; 10:3274-83. [PMID: 21926483 DOI: 10.4161/cc.10.19.17763] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
EAPII (also called TTRAP, TDP2), a protein identified a decade ago, has recently been shown to function as an oncogenic factor. This protein was also proven to be the first 5'- tyrosyl-DNA phosphodiesterase. EAPII has been demonstrated to have promiscuous protein associations, broad responsiveness to various extracellular signals, and pleiotropic functions in the development of human diseases including cancer and neurodegenerative disease. Emerging data suggest that EAPII is a multi-functional protein: EAPII repairs enzyme (topoisomerase)-mediated DNA damage by removing phosphotyrosine from DNA adducts; EAPII is involved in multiple signal transduction pathways such as TNF-TNFR, TGFβ and MAPK, and EAPII is responsive to immune defense, inflammatory response, virus infection and DNA toxins (chemo or radiation therapy). This review focuses on the current understanding of EAPII biology and its potential relations to many aspects of cancer development, including chromosome instability, tumorigenesis, tumor metastasis and chemoresistance, suggesting it as a potential target for intervention in cancer and other human diseases.
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Affiliation(s)
- Chunyang Li
- Winship Cancer Institute, Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, GA, USA
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Affiliation(s)
| | - Dennis Drayna
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892;
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Saviour P, Kumar S, Kiran U, Ravuri RR, Rao VR, Ramachandra NB. Allelic variants of DYX1C1 are not associated with dyslexia in India. INDIAN JOURNAL OF HUMAN GENETICS 2011; 14:99-102. [PMID: 20300304 PMCID: PMC2840802 DOI: 10.4103/0971-6866.45002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Dyslexia is a hereditary neurological disorder that manifests as an unexpected difficulty in learning to read despite adequate intelligence, education, and normal senses. The prevalence of dyslexia ranges from 3 to 15% of the school aged children. Many genetic studies indicated that loci on 6p21.3, 15q15-21, and 18p11.2 have been identified as promising candidate gene regions for dyslexia. Recently, it has been suggested that allelic variants of gene, DYX1C1 influence dyslexia. In the present study, exon 2 and 10 of DYX1C1 has been analyzed to verify whether these single nucleotide polymorphisms (SNPs) influence dyslexia, in our population. Our study identified 4 SNPs however, none of these SNPS were found to be significantly associated with dyslexia suggesting DYX1C1 allelic variants are not associated with dyslexia.
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Affiliation(s)
- Pushpa Saviour
- Human Genetics Laboratory, Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore-570 006, India
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Genetic variation in the KIAA0319 5' region as a possible contributor to dyslexia. Behav Genet 2011; 41:77-89. [PMID: 21207242 DOI: 10.1007/s10519-010-9434-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 12/15/2010] [Indexed: 10/18/2022]
Abstract
Reading disabilities (RD) have been linked and associated with markers on chromosome 6p with results from multiple independent samples pointing to KIAA0319 as a risk gene and specifically, the 5' region of this gene. Here we focus genetic studies on a 2.3 kb region spanning the predicted promoter, the first untranslated exon, and part of the first intron, a region we identified as a region of open chromatin. Using DNA from probands with RD, we screened for genetic variants and tested select variants for association. We identified 17 DNA variants in this sample of probands, 16 of which were previously reported in public databases and one previously identified in a screen of this region. Based on the allele frequencies in the probands compared to public databases, and on possible functional consequences of the variation, we selected seven variants to test for association in a sample of families with RD, in addition to four variants which had been tested previously. We also tested two markers 5' of this region that were previously reported as associated. The strongest evidence for association was observed with alleles of the microsatellite marker located in the first untranslated exon and haplotypes of that marker. These results support previous studies indicating the 5' region of the KIAA0319 gene as the location of risk alleles contributing to RD.
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Venkatesh SK, Siddaiah A, Padakannaya P, Ramachandra NB. An Examination of Candidate Gene SNPs for Dyslexia in an Indian Sample. Behav Genet 2011; 41:105-9. [DOI: 10.1007/s10519-010-9441-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 12/23/2010] [Indexed: 11/24/2022]
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Skiba T, Landi N, Wagner R, Grigorenko EL. In search of the perfect phenotype: an analysis of linkage and association studies of reading and reading-related processes. Behav Genet 2011; 41:6-30. [PMID: 21243420 PMCID: PMC3056345 DOI: 10.1007/s10519-011-9444-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 12/22/2010] [Indexed: 01/15/2023]
Abstract
Reading ability and specific reading disability (SRD) are complex traits involving several cognitive processes and are shaped by a complex interplay of genetic and environmental forces. Linkage studies of these traits have identified several susceptibility loci. Association studies have gone further in detecting candidate genes that might underlie these signals. These results have been obtained in samples of mainly European ancestry, which vary in their languages, inclusion criteria, and phenotype assessments. Such phenotypic heterogeneity across samples makes understanding the relationship between reading (dis)ability and reading-related processes and the genetic factors difficult; in addition, it may negatively influence attempts at replication. In moving forward, the identification of preferable phenotypes for future sample collection may improve the replicability of findings. This review of all published linkage and association results from the past 15 years was conducted to determine if certain phenotypes produce more replicable and consistent results than others.
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Affiliation(s)
| | - Nicole Landi
- Yale University & Haskins Laboratories, New Haven, CT, USA
| | | | - Elena L. Grigorenko
- Yale University, New Heaven, CT, USA
- Moscow State University, Moscow, Russia
- Columbia University, New York, NY, USA
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Meng H, Powers NR, Tang L, Cope NA, Zhang PX, Fuleihan R, Gibson C, Page GP, Gruen JR. A dyslexia-associated variant in DCDC2 changes gene expression. Behav Genet 2010; 41:58-66. [PMID: 21042874 DOI: 10.1007/s10519-010-9408-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Accepted: 10/08/2010] [Indexed: 01/28/2023]
Abstract
Reading disability (RD) or dyslexia is a common neurogenetic disorder. Two genes, KIAA0319 and DCDC2, have been identified by association studies of the DYX2 locus on 6p21.3. We previously identified a 2445 bp deletion, and a compound STR within the deleted region (BV677278), in intron 2 of DCDC2. The deletion and several alleles of the STR are strongly associated with RD (P = 0.00002). In this study we investigated whether BV677278 is a regulatory region for DCDC2 by electrophoretic mobility shift and luciferase reporter assays. We show that oligonucleotide probes from the STR bind nuclear protein from human brain, and that alleles of the STR have a range of DCDC2-specific enhancer activities. Five alleles displayed strong enhancer activity and increased gene expression, while allele 1 showed no enhancer activity. These studies suggest that the association of BV677278 with RD reflects a role as a modifier of DCDC2 expression.
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Affiliation(s)
- Haiying Meng
- Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, 464 Congress Avenue, New Haven, CT 06520-8081, USA
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Couto JM, Livne-Bar I, Huang K, Xu Z, Cate-Carter T, Feng Y, Wigg K, Humphries T, Tannock R, Kerr EN, Lovett MW, Bremner R, Barr CL. Association of reading disabilities with regions marked by acetylated H3 histones in KIAA0319. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:447-462. [PMID: 19588467 PMCID: PMC5381965 DOI: 10.1002/ajmg.b.30999] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reading disabilities (RDs) have been associated with chromosome 6p with recent studies pointing to two genes, DCDC2 and KIAA0319. In this study, markers across the 6p region were tested for association with RD. Our strongest findings were for association with markers in KIAA0319, although with the opposite alleles compared with a previous study. We also found association with markers in VMP, but not with DCDC2. Current evidence indicates that differential regulation of KIAA0319 and DCDC2 contributes to RD, thus we used chromatin immunoprecipitation coupled with genomic tiling arrays (ChIP-chip) to map acetylated histones, a molecular marker for regulatory elements, across a 500 kb genomic region covering the RD locus on 6p. This approach identified several regions marked by acetylated histones that mapped near associated markers, including intron 7 of DCDC2 and the 5' region of KIAA0319. The latter is located within the 70 kb region previously associated with differential expression of KIAA0319. Interestingly, five markers associated with RD in independent studies were also located within the 2.7 kb acetylated region, and six additional associated markers, including the most significant one in this study, were located within a 22 kb haplotype block that encompassed this region. Our data indicates that this putative regulatory region is a likely site of genetic variation contributing to RD in our sample, further narrowing the candidate region.
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Affiliation(s)
- Jillian M. Couto
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Izzy Livne-Bar
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Katherine Huang
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Zhaodong Xu
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Tasha Cate-Carter
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yu Feng
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Karen Wigg
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Tom Humphries
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rosemary Tannock
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N. Kerr
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maureen W. Lovett
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rod Bremner
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
| | - Cathy L. Barr
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada,Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Correspondence to: Prof. Cathy L. Barr, Toronto Western Research Institute, Toronto Western Hospital, MP14-302, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8.
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Abstract
Developmental dyslexia is a highly heritable disorder with a prevalence of at least 5% in school-aged children. Linkage studies have identified numerous loci throughout the genome that are likely to harbour candidate dyslexia susceptibility genes. Association studies and the refinement of chromosomal translocation break points in individuals with dyslexia have resulted in the discovery of candidate genes at some of these loci. A key function of many of these genes is their involvement in neuronal migration. This complements anatomical abnormalities discovered in dyslexic brains, such as ectopias, that may be the result of irregular neuronal migration.
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Couto JM, Gomez L, Wigg K, Ickowicz A, Pathare T, Malone M, Kennedy JL, Schachar R, Barr CL. Association of attention-deficit/hyperactivity disorder with a candidate region for reading disabilities on chromosome 6p. Biol Psychiatry 2009; 66:368-75. [PMID: 19362708 PMCID: PMC5750043 DOI: 10.1016/j.biopsych.2009.02.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/30/2009] [Accepted: 02/22/2009] [Indexed: 11/24/2022]
Abstract
BACKGROUND Reading disabilities (RD) and attention-deficit hyperactivity/disorder (ADHD) are two common childhood disorders that co-occur by chance more often than expected. Twin studies and overlapping genetic linkage findings indicate that shared genetic factors partially contribute to this comorbidity. Linkage of ADHD to 6p, an identified RD candidate locus, has previously been reported, suggesting the possibility of a pleiotropic gene at this locus. RD has been previously associated with five genes in the region, particularly DCDC2 and KIAA0319. METHODS To test whether these genes also contribute to ADHD, we investigated markers previously associated with RD for association with ADHD and ADHD symptoms in a sample of families with ADHD (n = 264). Markers were located in two subregions, VMP/DCDC2 and KIAA0319/TTRAP. RESULTS Across all analyses conducted, strong evidence for association was observed in the VMP/DCDC2 region. Association was equally strong with symptoms of both inattention and hyperactivity/impulsivity, suggesting that this locus contributes to both symptom dimensions. Markers were also tested for association with measures of reading skills (word identification, decoding); however, there was virtually no overlap in the markers associated with ADHD and those associated with reading skills in this sample. CONCLUSIONS Overall this study supports a previous linkage study of ADHD indicating a risk gene for ADHD on 6p and points to VMP or DCDC2 as the most likely candidates.
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Amin N, Aulchenko YS, Dekker MC, Ferdinand RF, van Spreeken A, Temmink AH, Verhulst FC, Oostra BA, van Duijn CM. Suggestive linkage of ADHD to chromosome 18q22 in a young genetically isolated Dutch population. Eur J Hum Genet 2009; 17:958-66. [PMID: 19156173 PMCID: PMC2986494 DOI: 10.1038/ejhg.2008.260] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/27/2008] [Accepted: 12/04/2008] [Indexed: 01/13/2023] Open
Abstract
Attention deficit/hyperactivity disorder (ADHD) is a common, highly heritable, neuropsychiatric disorder among children. Linkage studies in isolated populations have proved powerful to detect variants for complex diseases, such as ADHD. We performed a genome-wide linkage scan for ADHD in nine patients from a genetically isolated population in the Netherlands, who were linked to each other within 10 generations through multiple lines of descent. The genome-wide scan was performed with a set of 400 microsatellite markers with an average spacing of +/-10-12 cM. We performed multipoint parametric linkage analyses using both recessive and dominant models. Our genome scan pointed to several chromosomal regions that may harbour ADHD susceptibility genes. None exceeded the empirical genome-wide significance threshold, but the Log of odds (LOD) scores were >1.5 for regions 6p22 (Heterogenetic log of odds (HLOD)=1.67) and 18q21-22 (HLOD=2.13) under a recessive model. We followed up these two regions in a larger sample of ADHD patients (n=21, 9 initial and 12 extra patients). The LOD scores did not increase after increasing the sample size (6p22 (HLOD=1.51), 18q21-22 (HLOD=1.83)). However, the LOD score on 6p22 increased to 2 when a separate analysis was performed for the inattentive type ADHD children. The linkage region on chromosome 18q overlaps with the findings of association of rs2311120 (P=10(-5)) and rs4149601 (P=10(-4)) in the genome-wide association analysis for ADHD performed by the Genetic Association Information Network consortium. Furthermore, there was an excess of regions harbouring serotonin receptors (HTR1B, HTR1E, HTR4, HTR1D, and HTR6) that showed a LOD score >1 in our genome-wide scan.
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Affiliation(s)
- Najaf Amin
- Genetic Epidemiology Unit, Department of Epidemiology & Biostatistics and Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Yuri S Aulchenko
- Genetic Epidemiology Unit, Department of Epidemiology & Biostatistics and Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Marieke C Dekker
- Genetic Epidemiology Unit, Department of Epidemiology & Biostatistics and Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
- Department of Neurology, University Medical Centre, Nijmegen, The Netherlands
| | | | - Alwin van Spreeken
- Department of Neurology, Sint Franciscus Hospital, Roosendaal, The Netherlands
| | - Alfons H Temmink
- Department of Neurology, Amphia Hospital, Breda, The Netherlands
| | - Frank C Verhulst
- Department of Child and Adolescent Psychiatry, Erasmus MC Sophia, Rotterdam, The Netherlands
| | - Ben A Oostra
- Genetic Epidemiology Unit, Department of Epidemiology & Biostatistics and Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Cornelia M van Duijn
- Genetic Epidemiology Unit, Department of Epidemiology & Biostatistics and Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
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Couto JM, Gomez L, Wigg K, Cate-Carter T, Archibald J, Anderson B, Tannock R, Kerr EN, Lovett MW, Humphries T, Barr CL. The KIAA0319-like (KIAA0319L) gene on chromosome 1p34 as a candidate for reading disabilities. J Neurogenet 2009; 22:295-313. [PMID: 19085271 DOI: 10.1080/01677060802354328] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A locus on chromosome 1p34-36 (DYX8) has been linked to developmental dyslexia or reading disabilities (RD) in three independent samples. In the current study, we investigated a candidate gene KIAA0319-Like (KIAA0319L) within DYX8, as it is homologous to KIAA0319, a strong RD candidate gene on chromosome 6p (DYX2). Association was assessed by using five tagging single nucleotide polymorphisms in a sample of 291 nuclear families ascertained through a proband with reading difficulties. Evidence of association was found for a single marker (rs7523017; P=0.042) and a haplotype (P=0.031), with RD defined as a categorical trait in a subset of the sample (n=156 families) with a proband that made our criteria for RD. The same haplotype also showed evidence for association with quantitative measures of word-reading efficiency (i.e., a composite score of word identification and decoding; P=0.032) and rapid naming of objects and colors (P=0.047) when analyzed using the entire sample. Although the results from the current study are modestly significant and would not withstand a correction for multiple testing, KIAA0319L remains an intriguing positional and functional candidate for RD, especially when considered alongside the supporting evidence for its homolog KIAA0319 on chromosome 6p. Additional studies in independent samples are now required to confirm these findings.
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Affiliation(s)
- Jillian M Couto
- Genetics and Development Division, Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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24
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Platko JV, Wood FB, Pelser I, Meyer M, Gericke GS, O'Rourke J, Birns J, Purcell S, Pauls DL. Association of reading disability on chromosome 6p22 in the Afrikaner population. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:1278-87. [PMID: 18452150 DOI: 10.1002/ajmg.b.30774] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The genetic basis of reading disability (RD) has long been established through family and twin studies. More recently genetic linkage studies have identified genomic regions that appear to harbor susceptibility genes for RD. Association studies have been shown to have greater power for detecting genes of modest effect, particularly in genetically isolated populations. Hence, a case control study of RD was undertaken in the Afrikaner population in South Africa. Sixty-eight microsatellite markers in regions where linkages had been reported in previous studies were genotyped on 122 children with reading disability and 112 typically reading controls drawn from the same school population. A single allele of marker D6S299 showed a highly significant association with the RD phenotype (D6S299[229], P-value 0.000014). Other markers on other chromosomes also showed suggestive associations. Of particular interest were markers on chromosomes 1 and 15. These two regions have been implicated in studies of populations that formed the founding population in the Afrikaner population.
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Affiliation(s)
- Jill V Platko
- Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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25
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Abstract
Human quantitative trait locus (QTL) linkage mapping, although based on classical statistical genetic methods that have been around for many years, has been employed for genome-wide screening for only the last 10-15 years. In this time, there have been many success stories, ranging from QTLs that have been replicated in independent studies to those for which one or more genes underlying the linkage peak have been identified to a few with specific functional variants that have been confirmed in in vitro laboratory assays. Despite these successes, there is a general perception that linkage approaches do not work for complex traits, possibly because many human QTL linkage studies have been limited in sample size and have not employed the family configurations that maximize the power to detect linkage. We predict that human QTL linkage studies will continue to be productive for the next several years, particularly in combination with RNA expression level traits that are showing evidence of regulatory QTLs of large effect sizes and in combination with high-density genome-wide SNP panels. These SNP panels are being used to identify QTLs previously localized by linkage and linkage results are being used to place informative priors on genome-wide association studies.
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26
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QTLs identified for P3 amplitude in a non-clinical sample: importance of neurodevelopmental and neurotransmitter genes. Biol Psychiatry 2008; 63:864-73. [PMID: 17949694 DOI: 10.1016/j.biopsych.2007.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 06/26/2007] [Accepted: 09/07/2007] [Indexed: 11/20/2022]
Abstract
BACKGROUND The P3(00) event-related potential is an index of processing capacity (P3 amplitude) and stimulus evaluation (P3 latency) as well as a phenotypic marker of various forms of psychopathology where P3 abnormalities have been reported. METHODS A genome-wide linkage scan of 400-761 autosomal markers, at an average spacing of 5-10 centimorgans (cM), was completed in 647 twins/siblings (306 families mostly comprising dizygotic twins), mean age 16.3, range 15.4-20.1 years, for whom P3 amplitude and latency data were available. RESULTS Significant linkage for P3 amplitude was observed on chromosome 7q for the central recording site (logarithm-of-odds [LOD] = 3.88, p = .00002) and in the same region for both frontal (LOD = 2.19, p = .0015) and parietal (LOD = 1.67, p = .0053) sites, with multivariate analysis also identifying linkage in this region (LOD = 2.14, p = .0017). Suggestive linkage was also identified on 6p (LOD(max) = 2.49) and 12q (LOD(max) = 2.24), with other promising regions identified on 9q (LOD(max) = 2.14) and 10p (LOD(max) = 2.18). Less striking were the results for P3 latency; LOD > 1.5 were found on chromosomes 1q, 9q, 10q, 12q, and 19p. CONCLUSIONS This is a first step in the identification of genes for normal variation in the P3. Loci identified here for P3 amplitude suggest the possible importance of neurodevelopmental genes in addition to those influencing neurotransmitters, fitting with the evidence that P3 amplitude is sensitive to diverse types of brain abnormalities.
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Falcaro M, Pickles A, Newbury DF, Addis L, Banfield E, Fisher SE, Monaco AP, Simkin Z, Conti-Ramsden G. Genetic and phenotypic effects of phonological short-term memory and grammatical morphology in specific language impairment. GENES BRAIN AND BEHAVIOR 2007; 7:393-402. [PMID: 18005161 DOI: 10.1111/j.1601-183x.2007.00364.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Deficits in phonological short-term memory and aspects of verb grammar morphology have been proposed as phenotypic markers of specific language impairment (SLI) with the suggestion that these traits are likely to be under different genetic influences. This investigation in 300 first-degree relatives of 93 probands with SLI examined familial aggregation and genetic linkage of two measures thought to index these two traits, non-word repetition and tense marking. In particular, the involvement of chromosomes 16q and 19q was examined as previous studies found these two regions to be related to SLI. Results showed a strong association between relatives' and probands' scores on non-word repetition. In contrast, no association was found for tense marking when examined as a continuous measure. However, significant familial aggregation was found when tense marking was treated as a binary measure with a cut-off point of -1.5 SD, suggestive of the possibility that qualitative distinctions in the trait may be familial while quantitative variability may be more a consequence of non-familial factors. Linkage analyses supported previous findings of the SLI Consortium of linkage to chromosome 16q for phonological short-term memory and to chromosome 19q for expressive language. In addition, we report new findings that relate to the past tense phenotype. For the continuous measure, linkage was found on both chromosomes, but evidence was stronger on chromosome 19. For the binary measure, linkage was observed on chromosome 19 but not on chromosome 16.
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Affiliation(s)
- M Falcaro
- Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
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28
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Caylak E. A review of association and linkage studies for genetical analyses of learning disorders. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:923-43. [PMID: 17510947 DOI: 10.1002/ajmg.b.30537] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Learning disorders (LD) commonly comprise of a heterogeneous group of disorders manifested by unexpected problems in some children's experiences in the academic performance arena. These problems especially comprise of a variety of disorders which may be subclassified to attention-deficit hyperactivity disorder (ADHD), reading disability (RD), specific language impairment (SLI), speech-sound disorder (SSD), and dyspraxia. The aim of this review is to summarize the current molecular studies and some of the most exciting recent developments in molecular genetic research on LD. The findings for the association and linkage of LD with candidate genes will help to set the research agendas for future studies to follow.
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Affiliation(s)
- Emrah Caylak
- Department of Biochemistry and Clinical Biochemistry, Firat University, School of Medicine, Elazig, Turkey.
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29
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Abstract
Reading abilities are acquired only through specific teaching and training. A significant proportion of children fail to achieve these skills despite normal intellectual abilities and an appropriate opportunity to learn. Difficulty in learning to read is attributable to specific dysfunctions of the brain, which so far remain poorly understood. However, it is recognized that the neurological basis for dyslexia, or reading disability, is caused in large part by genetic factors. Linkage studies have successfully identified several regions of the human genome that are likely to harbor susceptibility genes for dyslexia. In the past few years there have been exciting advances with the identification of four candidate genes located within three of these linked chromosome regions: DYX1C1 on chromosome 15, ROBO1 on chromosome 3, and KIAA0319 and DCDC2 on chromosome 6. Functional studies of these genes are offering new insights about the biological mechanisms underlying the development of dyslexia and, in general, of cognition.
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Affiliation(s)
- Silvia Paracchini
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
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30
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Genetik der Lese- und Rechtschreibstörung. Monatsschr Kinderheilkd 2007. [DOI: 10.1007/s00112-007-1479-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Schulte-Körne G, Ziegler A, Deimel W, Schumacher J, Plume E, Bachmann C, Kleensang A, Propping P, Nöthen MM, Warnke A, Remschmidt H, König IR. Interrelationship and Familiality of Dyslexia Related Quantitative Measures. Ann Hum Genet 2007; 71:160-75. [PMID: 17038000 DOI: 10.1111/j.1469-1809.2006.00312.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dyslexia is a complex gene-environment disorder with poorly understood etiology that affects about 5% of school-age children. Dyslexia occurs in all languages and is associated with a high level of social and psychological morbidity for the individual and their family; approximately 40-50% have persistent disability into adulthood. The core symptoms are word reading and spelling deficits, but several other cognitive components influence the core phenotype. A broad spectrum of dyslexia related phenotypes, including phonological decoding, phoneme awareness, orthographic processing, short-term memory, rapid naming and basic mathematical abilities, were investigated in large sample of 287 German dyslexia families. We explored the interrelationship between the component phenotypes using correlation and principal component analyses (PCA). In addition, we estimated familiality for phenotypes as well as for the factors suggested by PCA. The correlation between the component phenotypes varied between -0.1 and 0.7. The PCA resulted in three factors: a general dyslexia factor, a speed of processing factor and a mathematical abilities factor. The familiality estimates of single components and factors ranged between 0.25 and 0.63. Instead of analyzing single dyslexia-related components, multivariate analyses including factor analytic approaches may help in the identification of susceptibility genes.
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Affiliation(s)
- G Schulte-Körne
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Marburg, Marburg, Germany.
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32
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Goldston DB, Walsh A, Mayfield Arnold E, Reboussin B, Sergent Daniel S, Erkanli A, Nutter D, Hickman E, Palmes G, Snider E, Wood FB. Reading problems, psychiatric disorders, and functional impairment from mid- to late adolescence. J Am Acad Child Adolesc Psychiatry 2007; 46:25-32. [PMID: 17195726 DOI: 10.1097/01.chi.0000242241.77302.f4] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine psychiatric morbidity and functional impairment of adolescents with and without poor reading skills during mid- to late adolescence. METHOD The sample consisted of 188 adolescents, 94 with poor reading skills and 94 with typical reading skills, screened from a larger sample in the public schools at age 15. To assess psychiatric disorders, participants were assessed annually with the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic Version (up to 4.5 years; maximum age, 20 years). Functional impairment was assessed with the Child and Adolescent Functional Assessment Scale. RESULTS Adolescents with poor reading skills evidenced higher rates of current attention-deficit/hyperactivity, affective, and anxiety disorders, particularly social phobia and generalized anxiety disorder. Anxiety disorders but not affective disorders were related to reading status after controlling for attention-deficit/hyperactivity disorder. Adolescents with poor reading evidenced more functional impairment across multiple areas than youths with typical reading skills, even after considering the presence of comorbid attention-deficit/hyperactivity disorder. CONCLUSIONS The increased psychiatric morbidity and functional impairment of adolescents with reading problems highlight the importance of developing interventions that help these youths address reading deficits and associated vulnerabilities during the last years of secondary school.
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Affiliation(s)
- David B Goldston
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC..
| | - Adam Walsh
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Elizabeth Mayfield Arnold
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Beth Reboussin
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Stephanie Sergent Daniel
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Alaattin Erkanli
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Dennis Nutter
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Enith Hickman
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Guy Palmes
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Erica Snider
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
| | - Frank B Wood
- Drs. Goldston and Erkanli are with the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, Durham, NC; Dr. Reboussin is with the Department of Public Health Sciences, Dr. Wood is with the Department of Neurology, and Drs. Arnold, Daniel, Nutter, and Palmes, Mr. Walsh, Ms. Snider, and Ms. Hickman are affiliated with the Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC; Dr. Nutter is now affiliated with the Northeast Georgia Medical Center, Gainesville; and Ms. Hickman is employed by the U.S. Department of Health and Human Services, Washington, DC
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Harold D, Paracchini S, Scerri T, Dennis M, Cope N, Hill G, Moskvina V, Walter J, Richardson AJ, Owen MJ, Stein JF, Green ED, O'Donovan MC, Williams J, Monaco AP. Further evidence that the KIAA0319 gene confers susceptibility to developmental dyslexia. Mol Psychiatry 2006; 11:1085-91, 1061. [PMID: 17033633 DOI: 10.1038/sj.mp.4001904] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The DYX2 locus on chromosome 6p22.2 is the most replicated region of linkage to developmental dyslexia (DD). Two candidate genes within this region have recently been implicated in the disorder: KIAA0319 and DCDC2. Variants within DCDC2 have shown association with DD in a US and a German sample. However, when we genotyped these specific variants in two large, independent UK samples, we obtained only weak, inconsistent evidence for their involvement in DD. Having previously found evidence that variation in the KIAA0319 gene confers susceptibility to DD, we sought to refine this genetic association by genotyping 36 additional SNPs in the gene. Nine SNPs, predominantly clustered around the first exon, showed the most significant association with DD in one or both UK samples, including rs3212236 in the 5' flanking region (P = 0.00003) and rs761100 in intron 1 (P = 0.0004). We have thus refined the region of association with developmental dyslexia to putative regulatory sequences around the first exon of the KIAA0319 gene, supporting the presence of functional mutations that could affect gene expression. Our data also suggests a possible interaction between KIAA0319 and DCDC2, which requires further testing.
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Affiliation(s)
- D Harold
- Department of Psychological Medicine, Cardiff University, Heath Park, Cardiff, UK
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Olson RK. Genes, environment, and dyslexia. The 2005 Norman Geschwind Memorial Lecture. ANNALS OF DYSLEXIA 2006; 56:205-38. [PMID: 17849199 DOI: 10.1007/s11881-006-0010-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 09/13/2006] [Indexed: 05/17/2023]
Abstract
This article presents an overview of some methods and results from our continuing studies of genetic and environmental influences on dyslexia, and on individual differences across the normal range that have been conducted over the past 25 years in the Colorado Learning Disabilities Research Center (CLDRC) and in related projects. CLDRC investigators compare the similarities of identical twin pairs who share all their genes and fraternal twins who share half their segregating genes to assess the balance of genetic, shared family environment, and nonshared environment influences on dyslexia and on individual differences across the normal range. We have learned that among the children we have studied in Colorado, group deficits in reading (dyslexia) and individual differences in reading across the normal range are primarily due to genetic influences, and these genetic influences are often shared with some of the same genetic influences on deficits and individual differences in language and ADHD. We have also learned from our molecular-genetic linkage studies that there are regions on several chromosomes likely to contain genes that influence dyslexia. Several specific genes within these regions have been tentatively identified through molecular-genetic association analyses, but much more research is needed to understand the pathways among specific genes, regions of noncoding DNA that regulate the activity of those genes, the brain, and dyslexia. I conclude with a discussion of our research on individual differences in early reading development, on the role of early learning constraints in dyslexia, and on how genetic influences are expressed through their interaction and correlation with the environment.
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Affiliation(s)
- Richard K Olson
- Department of Psychology, University of Colorado, UCB 345, Boulder, CO 80309, USA.
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Lewis BA, Shriberg LD, Freebairn LA, Hansen AJ, Stein CM, Taylor HG, Iyengar SK. The genetic bases of speech sound disorders: evidence from spoken and written language. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2006; 49:1294-312. [PMID: 17197497 DOI: 10.1044/1092-4388(2006/093)] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The purpose of this article is to review recent findings suggesting a genetic susceptibility for speech sound disorders (SSD), the most prevalent communication disorder in early childhood. The importance of genetic studies of SSD and the hypothetical underpinnings of these genetic findings are reviewed, as well as genetic associations of SSD with other language and reading disabilities. The authors propose that many genes contribute to SSD. They further hypothesize that some genes contribute to SSD disorders alone, whereas other genes influence both SSD and other written and spoken language disorders. The authors postulate that underlying common cognitive traits, or endophenotypes, are responsible for shared genetic influences of spoken and written language. They review findings from their genetic linkage study and from the literature to illustrate recent developments in this area. Finally, they discuss challenges for identifying genetic influence on SSD and propose a conceptual framework for study of the genetic basis of SSD.
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Affiliation(s)
- Barbara A Lewis
- Behavioral Pediatrics and Psychology 6038, Rainbow Babies and Children's Hospital, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-6038, USA.
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Daniel SS, Walsh AK, Goldston DB, Arnold EM, Reboussin BA, Wood FB. Suicidality, school dropout, and reading problems among adolescents. JOURNAL OF LEARNING DISABILITIES 2006; 39:507-14. [PMID: 17165618 DOI: 10.1177/00222194060390060301] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The purpose of this study was to examine the risk of suicidal ideation and suicide attempts and school dropout among youth with poor reading in comparison to youth with typical reading (n = 188) recruited from public schools at the age of 15. In a prospective naturalistic study, youth and parents participated in repeated research assessments to obtain information about suicide ideation and attempts, psychiatric and sociodemographic variables, and school dropout. Youth with poor reading ability were more likely to experience suicidal ideation or attempts and more likely to drop out of school than youth with typical reading, even after controlling for sociodemographic and psychiatric variables. Suicidality and school dropout were strongly associated with each other. Prevention efforts should focus on better understanding the relationship between these outcomes, as well as on the developmental paths leading up to these behaviors among youth with reading difficulties.
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Affiliation(s)
- Stephanie S Daniel
- Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1087, USA.
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Schulte-Körne G, Warnke A, Remschmidt H. Zur Genetik der Lese-Rechtschreibschwäche. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2006; 34:435-44. [PMID: 17094062 DOI: 10.1024/1422-4917.34.6.435] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Zusammenfassung: Die Lese-Rechtschreibstörung (LRS) ist eine der häufigsten Entwicklungsstörungen. Die Ursachen dieser komplexen Störung sind bisher nur kaum verstanden. Familienuntersuchungen zeigen, dass die LRS familiär gehäuft auftritt und dass das Risiko für ein Geschwisterkind, eine LRS zu entwickeln, ca. 3,5fach erhöht ist. Verschiedene kognitive Fähigkeiten sind mit der LRS korreliert. Hierzu gehören die phonologische Bewusstheit, orthographisches Wissen, phonologisches Dekodieren, auditives Kurzzeitgedächtnis und schnelles Benennen. Eine familiäre Häufung dieser mit der LRS korrelierten Dimensionen und eine hohe Erblichkeit (Heritabilität) wurden wiederholt gefunden. Die Heritabilität für die Lesefähigkeit liegt zwischen 50-60%, für die Rechtschreibstörung zwischen 50 und 70%. Durch genomweite Kopplungsuntersuchungen wurden bisher 9 Kandidatengenregionen (DYX1-9) identifiziert. Vier Kandidatengene, DCDC2, KIAA0319, ROBO1 und DYX1C1 wurden kürzlich beschrieben. Diese beeinflussen die neuronale Migration und sind daher funktionell aussichtsreiche Kandidatengene für die LRS. Allerdings konnte bisher keine funktionell relevante Mutation gefunden werden. Die Komorbidität zwischen LRS und ADHD sowie LRS und Sprachentwicklungsstörungen könnte zum Teil durch gemeinsame genetische Faktoren erklärt werden. In der Zukunft wird es für die Ursachenforschung der LRS entscheidend sein, möglichst alle ursachenrelevanten Dimensionen gemeinsam an ausreichend großen Stichproben zu untersuchen. Neben den relevanten neurobiologischen Faktoren sollten auch Umweltfaktoren und die verschiedenen Interaktionen, wie z.B. Gen-Umwelt und Gen-Gen-Interaktionen untersucht werden. In einem europäischen, kollaborativen Forschungsvorhaben (NeuroDys) wird weltweit die größte Stichprobe von Kindern mit einer LRS gesammelt und untersucht, um durch ein verbessertes Ursachenverständnis unter Einschluss der Identifikation von genetischen Risikofaktoren die Komplexität des Störungsbildes besser zu verstehen und perspektivisch spezifische Therapien zu entwickeln.
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Affiliation(s)
- Gerd Schulte-Körne
- 1 Klinik für Kinder- und Jugendpsychiatrie, Psychosomatik und Psychotherapie, Klinikum der Universität München, Pettenkoferstrasse 8a, DE-80336 München
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Richards TL, Aylward EH, Field KM, Grimme AC, Raskind W, Richards AL, Nagy W, Eckert M, Leonard C, Abbott RD, Berninger VW. Converging evidence for triple word form theory in children with dyslexia. Dev Neuropsychol 2006; 30:547-89. [PMID: 16925475 DOI: 10.1207/s15326942dn3001_3] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
This article has 3 parts. The 1st part provides an overview of the family genetics, brain imaging, and treatment research in the University of Washington Multidisciplinary Learning Disabilities Center (UWLDC) over the past decade that points to a probable genetic basis for the unusual difficulty that individuals with dyslexia encounter in learning to read and spell. Phenotyping studies have found evidence that phonological, orthographic, and morphological word forms and their parts may contribute uniquely to this difficulty. At the same time, reviews of treatment studies in the UWLDC (which focused on children in Grades 4 to 6) and other research centers provide evidence for the plasticity of the brain in individuals with dyslexia. The 2nd part reports 4 sets of results that extend previously published findings based on group analyses to those based on analyses of individual brains and that support triple word form awareness and mapping theory: (a) distinct brain signatures for the phonological, morphological, and orthographic word forms; (b) crossover effects between phonological and morphological treatments and functional magentic resonance imaging (fMRI) tasks in response to instruction, suggestive of cross-word form computational and mapping processes; (c) crossover effects between behavioral measures of phonology or morphology and changes in fMRI activation following treatment; and (d) change in the relationship between structural MRI and functional magnetic resonance spectroscopy (fMRS) lactate activation in right and left inferior frontal gyri following treatment emphasizing the phonological, morphological, and orthographic word forms. In the 3rd part we discuss the next steps in this programmatic research to move beyond word form alone.
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Affiliation(s)
- Todd L Richards
- Department of Radiology, University of Washington, Seattle, WA 98195, USA.
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Abstract
Reading reflects the complex integration of several cognitive processes and proves more difficult to achieve for a significant proportion of the population. Developmental dyslexia (DD), or specific reading disability, is influenced by genes, a fact that has led several research groups to attempt to identify susceptibility genes through the sequential analysis of genetic linkage and association. Strong evidence has now emerged for the presence of genes influencing DD at several chromosomal loci and for at least one of these, there is evidence implicating specific genes. In this review, we present the evidence for a genetic contribution to DD and its component processes and review the current status of molecular genetic research aimed at identifying susceptibility genes for this common, complex disorder.
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Affiliation(s)
- Julie Williams
- Department of Psychological Medicine, Cardiff University, Henry Wellcome Building, Heath Park, Cardiff CF14 4XN, UK.
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McGrath LM, Smith SD, Pennington BF. Breakthroughs in the search for dyslexia candidate genes. Trends Mol Med 2006; 12:333-41. [PMID: 16781891 DOI: 10.1016/j.molmed.2006.05.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 04/18/2006] [Accepted: 05/25/2006] [Indexed: 12/18/2022]
Abstract
Four genes have recently been proposed as candidates for dyslexia: dyslexia susceptibility 1 candidate 1 (DYX1C1), roundabout Drosophila homolog 1 (ROBO1), doublecortin domain-containing protein 2 (DCDC2) and KIAA0319. Each gene is implicated in global brain-development processes such as neural migration and axonal guidance, with the exception of DYX1C1, the function of which is still unknown. The most immediate clinical prospect of the discovery of these genes is the possibility of early identification of dyslexia via genetic screening. However, research efforts have yet to identify a functional mutation in any of these genes. When causal variants are identified, they will need to be considered within a multifactorial framework, which is likely to involve gene-gene and gene-environment interactions, to make accurate predictions of diagnostic status.
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Affiliation(s)
- Lauren M McGrath
- University of Denver, Department of Psychology, Frontier Hall, 2155 S. Race St., Denver, CO 80208, USA.
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Sotozaki H, Parlow S. Interhemispheric communication involving multiple tasks: A study of children with dyslexia. BRAIN AND LANGUAGE 2006; 98:89-101. [PMID: 16690112 DOI: 10.1016/j.bandl.2006.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 01/20/2006] [Accepted: 04/02/2006] [Indexed: 05/09/2023]
Abstract
The study investigated whether inefficient interhemispheric communication is involved in developmental dyslexia using multiple tasks. A finger localization task, rhyming judgment task, primed lexical decision task, and a visual half-field presentation paradigm were used. Nineteen dyslexic children (mean age = 13.1 years) were compared with 26 chronological age-matched normal children. Although the dyslexic group demonstrated significantly slower and less accurate performance in all three tasks, there was no significant group difference in term of interhemispheric communication. However, priming effects demonstrated by the dyslexic group (p < .05) further indicate that their reading problems may stem from the word retrieval process from the long term memory.
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Affiliation(s)
- Hiroko Sotozaki
- Department of Psychology, Carleton University, Ottawa, Ont., Canada.
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42
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Paracchini S, Thomas A, Castro S, Lai C, Paramasivam M, Wang Y, Keating BJ, Taylor JM, Hacking DF, Scerri T, Francks C, Richardson AJ, Wade-Martins R, Stein JF, Knight JC, Copp AJ, Loturco J, Monaco AP. The chromosome 6p22 haplotype associated with dyslexia reduces the expression of KIAA0319, a novel gene involved in neuronal migration. Hum Mol Genet 2006; 15:1659-66. [PMID: 16600991 DOI: 10.1093/hmg/ddl089] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dyslexia is one of the most prevalent childhood cognitive disorders, affecting approximately 5% of school-age children. We have recently identified a risk haplotype associated with dyslexia on chromosome 6p22.2 which spans the TTRAP gene and portions of THEM2 and KIAA0319. Here we show that in the presence of the risk haplotype, the expression of the KIAA0319 gene is reduced but the expression of the other two genes remains unaffected. Using in situ hybridization, we detect a very distinct expression pattern of the KIAA0319 gene in the developing cerebral neocortex of mouse and human fetuses. Moreover, interference with rat Kiaa0319 expression in utero leads to impaired neuronal migration in the developing cerebral neocortex. These data suggest a direct link between a specific genetic background and a biological mechanism leading to the development of dyslexia: the risk haplotype on chromosome 6p22.2 down-regulates the KIAA0319 gene which is required for neuronal migration during the formation of the cerebral neocortex.
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Affiliation(s)
- Silvia Paracchini
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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Igo RP, Chapman NH, Berninger VW, Matsushita M, Brkanac Z, Rothstein JH, Holzman T, Nielsen K, Raskind WH, Wijsman EM. Genomewide scan for real-word reading subphenotypes of dyslexia: novel chromosome 13 locus and genetic complexity. Am J Med Genet B Neuropsychiatr Genet 2006; 141B:15-27. [PMID: 16331673 PMCID: PMC2556979 DOI: 10.1002/ajmg.b.30245] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dyslexia is a common learning disability exhibited as a delay in acquiring reading skills despite adequate intelligence and instruction. Reading single real words (real-word reading, RWR) is especially impaired in many dyslexics. We performed a genome scan, using variance components (VC) linkage analysis and Bayesian Markov chain Monte Carlo (MCMC) joint segregation and linkage analysis, for three quantitative measures of RWR in 108 multigenerational families, with follow up of the strongest signals with parametric LOD score analyses. We used single-word reading efficiency (SWE) to assess speed and accuracy of RWR, and word identification (WID) to assess accuracy alone. Adjusting SWE for WID provided a third measure of RWR efficiency. All three methods of analysis identified a strong linkage signal for SWE on chromosome 13q. Based on multipoint analysis with 13 markers we obtained a MCMC intensity ratio (IR) of 53.2 (chromosome-wide P < 0.004), a VC LOD score of 2.29, and a parametric LOD score of 2.94, based on a quantitative-trait model from MCMC segregation analysis (SA). A weaker signal for SWE on chromosome 2q occurred in the same location as a significant linkage peak seen previously in a scan for phonological decoding. MCMC oligogenic SA identified three models of transmission for WID, which could be assigned to two distinct linkage peaks on chromosomes 12 and 15. Taken together, these results indicate a locus for efficiency and accuracy of RWR on chromosome 13, and a complex model for inheritance of RWR accuracy with loci on chromosomes 12 and 15.
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Affiliation(s)
- Robert P. Igo
- Department of Medicine, University of Washington, Seattle, WA
- Department of Biostatistics, University of Washington, Seattle, WA
| | | | | | - Mark Matsushita
- Department of Medicine, University of Washington, Seattle, WA
| | - Zoran Brkanac
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA
| | | | | | - Kathleen Nielsen
- Department of Educational Psychology, University of Washington, Seattle, WA
| | - Wendy H. Raskind
- Department of Medicine, University of Washington, Seattle, WA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA
| | - Ellen M. Wijsman
- Department of Medicine, University of Washington, Seattle, WA
- Department of Biostatistics, University of Washington, Seattle, WA
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Petrill SA, Deater-Deckard K, Thompson LA, Dethorne LS, Schatschneider C. Reading skills in early readers: genetic and shared environmental influences. JOURNAL OF LEARNING DISABILITIES 2006; 39:48-55. [PMID: 16512082 PMCID: PMC2648050 DOI: 10.1177/00222194060390010501] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The present study combined parallel data from the Northeast-Northwest Collaborative Adoption Projects (N2CAP) and the Western Reserve Reading Project (WRRP) to examine sibling similarity and quantitative genetic model estimates for measures of reading skills in 272 school-age sibling pairs from three family types (monozygotic twins, dizygotic twins, and unrelated adoptive siblings). The study included measures of letter and word identification, phonological awareness, phonological decoding, rapid automatized naming, and general cognitive ability. Estimates of additive genetic effects and shared environmental effects were moderate and significant. Furthermore, shared environmental effects estimated in twins were generally similar in magnitude to adoptive sibling correlations, suggesting highly replicable estimates across different study designs.
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Affiliation(s)
- Stephen A Petrill
- Center for Developmental and Health Genetics, Pennsylvania State University, University Park 16802, USA.
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45
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Schumacher J, Anthoni H, Dahdouh F, König IR, Hillmer AM, Kluck N, Manthey M, Plume E, Warnke A, Remschmidt H, Hülsmann J, Cichon S, Lindgren CM, Propping P, Zucchelli M, Ziegler A, Peyrard-Janvid M, Schulte-Körne G, Nöthen MM, Kere J. Strong genetic evidence of DCDC2 as a susceptibility gene for dyslexia. Am J Hum Genet 2006; 78:52-62. [PMID: 16385449 PMCID: PMC1380223 DOI: 10.1086/498992] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 10/07/2005] [Indexed: 11/03/2022] Open
Abstract
We searched for linkage disequilibrium (LD) in 137 triads with dyslexia, using markers that span the most-replicated dyslexia susceptibility region on 6p21-p22, and found association between the disease and markers within the VMP/DCDC2/KAAG1 locus. Detailed refinement of the LD region, involving sequencing and genotyping of additional markers, showed significant association within DCDC2 in single-marker and haplotype analyses. The association appeared to be strongest in severely affected patients. In a second step, the study was extended to include an independent sample of 239 triads with dyslexia, in which the association--in particular, with the severe phenotype of dyslexia--was confirmed. Our expression data showed that DCDC2, which contains a doublecortin homology domain that is possibly involved in cortical neuron migration, is expressed in the fetal and adult CNS, which--together with the hypothesized protein function--is in accordance with findings in dyslexic patients with abnormal neuronal migration and maturation.
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46
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Petrill SA, Thompson LA, Deater-Deckard K, Dethorne LS, Schatschneider C. Genetic and Environmental Effects of Serial Naming and Phonological Awareness on Early Reading Outcomes. JOURNAL OF EDUCATIONAL PSYCHOLOGY 2006; 98:112-121. [PMID: 19444324 DOI: 10.1037/0022-0663.98.1.112] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The current study involved 281 early-school-age twin pairs (118 monozygotic, 163 same-sex dizygotic) participating in the ongoing Western Reserve Reading Project (S. A. Petrill, K. Deater-Deckard, L. A. Thompson, & C. Schatschneider, 2006). Twins were tested in their homes by separate examiners on a battery of reading-related skills including phonological awareness, rapid automatized naming, word knowledge, and phonological decoding. Results suggested that a core genetic factor accounted for a significant portion of the covariance between phonological awareness, rapid naming, and reading outcomes. However, shared environmental influences related to phonological awareness were also associated with reading skills.
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47
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Dick DM, Aliev F, Bierut L, Goate A, Rice J, Hinrichs A, Bertelsen S, Wang JC, Dunn G, Kuperman S, Schuckit M, Nurnberger J, Porjesz B, Beglieter H, Kramer J, Hesselbrock V. Linkage analyses of IQ in the collaborative study on the genetics of alcoholism (COGA) sample. Behav Genet 2005; 36:77-86. [PMID: 16341907 DOI: 10.1007/s10519-005-9009-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 09/12/2005] [Indexed: 10/25/2022]
Abstract
Intelligence, as measured by standardized psychological tests, has been shown to be highly heritable, though identifying specific genes influencing general intelligence has proven difficult. We conducted genome-wide linkage analyses to identify chromosomal regions containing genes influencing intelligence, as measured by WAIS full-scale IQ (FSIQ), performance IQ (PIQ) and verbal IQ (VIQ). Non-parametric multipoint linkage analyses were conducted with Merlin-regress software, using a sample of 1,111 genotyped and phenotyped individuals from 201 families, ascertained as part of the Collaborative Study on the Genetics of Alcoholism (COGA). The strongest evidence of linkage was obtained for FSIQ on chromosome 6 (LOD=3.28, 12 cM) near the marker D6S1006. This region was also implicated with suggestive linkage in a recently published genome screen of IQ in Australian and Dutch twin pairs, and it has been implicated in linkage studies of developmental dyslexia. Our findings provide further support that chromosome 6p contains gene(s) affecting intelligence.
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Affiliation(s)
- Danielle M Dick
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, USA.
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Wood FB, Hill DF, Meyer MS, Flowers DL. Predictive assessment of reading. ANNALS OF DYSLEXIA 2005; 55:193-216. [PMID: 17849193 DOI: 10.1007/s11881-005-0011-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 10/03/2005] [Indexed: 05/17/2023]
Abstract
Study 1 retrospectively analyzed neuropsychological and psychoeducational tests given to N=220 first graders, with follow-up assessments in third and eighth grade. Four predictor constructs were derived: (1) Phonemic Awareness, (2) Picture Vocabulary, (3) Rapid Naming, and (4) Single Word Reading. Together, these accounted for 88%, 76%, 69%, and 69% of the variance, respectively, in first, third, and eighth grade Woodcock Johnson Broad Reading and eighth grade Gates-MacGinitie. When Single Word Reading was excluded from the predictors, the remaining predictors still accounted for 71%, 65%, 61%, and 65% of variance in the respective outcomes. Secondary analyses of risk of low outcome showed sensitivities/specificities of 93.0/91.0, and 86.4/84.9, respectively, for predicting which students would be in the bottom 15% and 30% of actual first grade WJBR. Sensitivities/specificities were 84.8/83.3 and 80.2/81.3, respectively, for predicting the bottom 15% and 30% of actual third grade WJBR outcomes; eighth grade outcomes had sensitivities/specificities of 80.0/80.0 and 85.7/83.1, respectively, for the bottom 15% and 30% of actual eighth grade WJBR scores. Study 2 cross-validated the concurrent predictive validities in an N=500 geographically diverse sample of late kindergartners through third graders, whose ethnic and racial composition closely approximated the national early elementary school population. New tests of the same four predictor domains were used, together taking only 15 minutes to administer by teachers; the new Woodcock-Johnson III Broad Reading standard score was the concurrent criterion, whose testers were blind to the predictor results. This cross-validation showed 86% of the variance accounted for, using the same regression weights as used in Study 1. With these weights, sensitivity/specificity values for the 15% and 30% thresholds were, respectively, 91.3/88.0 and 94.1/89.1. These validities and accuracies are stronger than others reported for similar intervals in the literature.
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Affiliation(s)
- Frank B Wood
- Wake Forest University Health Sciences, Winston-Salem, NC 27157-1043, USA.
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Galaburda AM. Dyslexia--a molecular disorder of neuronal migration: the 2004 Norman Geschwind Memorial Lecture. ANNALS OF DYSLEXIA 2005; 55:151-65. [PMID: 17849191 DOI: 10.1007/s11881-005-0009-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Accepted: 09/12/2005] [Indexed: 05/17/2023]
Abstract
For 25 years now, there has been a serious attempt to get at the fundamental cause(s) of dyslexia in our laboratory. A great deal of research has been carried out on the psychological and brain underpinnings of the linguistic dysfunctions seen in dyslexia, but attempts to get at its cause have been limited. Initially, observations were made on the brains of persons with dyslexia who had died and their brains donated for research. These observations were modeled in animal models in order to better understand the full extent of anatomical and developmental brain characteristics. More recently, models have begun to employ genetic manipulations in order to close the gap between genes, brain, and behavior. In this article based on a lecture given in memory of Dr. Norman Geschwind to the International Dyslexia Association assembly in Philadelphia in 2004, I outline the history of the research leading up to the most recent findings. These findings consist of experiments using methods that interfere with the function of DNA, using as constructs genes that have been implicated in dyslexia, which cause developmental problems of neuronal migration in rats, secondary brain changes in response to the migration problems, and abnormal processing of sounds.
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Affiliation(s)
- Albert M Galaburda
- Harvard Medical School, Division of Behavioral Neurology and Memory Disorders, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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Meng H, Smith SD, Hager K, Held M, Liu J, Olson RK, Pennington BF, DeFries JC, Gelernter J, O'Reilly-Pol T, Somlo S, Skudlarski P, Shaywitz SE, Shaywitz BA, Marchione K, Wang Y, Paramasivam M, LoTurco JJ, Page GP, Gruen JR. DCDC2 is associated with reading disability and modulates neuronal development in the brain. Proc Natl Acad Sci U S A 2005; 102:17053-8. [PMID: 16278297 PMCID: PMC1278934 DOI: 10.1073/pnas.0508591102] [Citation(s) in RCA: 267] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
DYX2 on 6p22 is the most replicated reading disability (RD) locus. By saturating a previously identified peak of association with single nucleotide polymorphism markers, we identified a large polymorphic deletion that encodes tandem repeats of putative brain-related transcription factor binding sites in intron 2 of DCDC2. Alleles of this compound repeat are in significant disequilibrium with multiple reading traits. RT-PCR data show that DCDC2 localizes to the regions of the brain where fluent reading occurs, and RNA interference studies show that down-regulation alters neuronal migration. The statistical and functional studies are complementary and are consistent with the latest clinical imaging data for RD. Thus, we propose that DCDC2 is a candidate gene for RD.
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Affiliation(s)
- Haiying Meng
- Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, New Haven, CT 06520, USA
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