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Exploring Genetic and Neural Risk of Specific Reading Disability within a Nuclear Twin Family Case Study: A Translational Clinical Application. J Pers Med 2023; 13:jpm13010156. [PMID: 36675818 PMCID: PMC9862148 DOI: 10.3390/jpm13010156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
Imaging and genetic studies have characterized biological risk factors contributing to specific reading disability (SRD). The current study aimed to apply this literature to a family of twins discordant for SRD and an older sibling with reading difficulty. Intraclass correlations were used to understand the similarity of imaging phenotypes between pairs. Reading-related genes and brain region phenotypes, including asymmetry indices representing the relative size of left compared to right hemispheric structures, were descriptively examined. SNPs that corresponded between the SRD siblings and not the typically developing (TD) siblings were in genes ZNF385D, LPHN3, CNTNAP2, FGF18, NOP9, CMIP, MYO18B, and RBFOX2. Imaging phenotypes were similar among all sibling pairs for grey matter volume and surface area, but cortical thickness in reading-related regions of interest (ROIs) was more similar among the siblings with SRD, followed by the twins, and then the TD twin and older siblings, suggesting cortical thickness may differentiate risk for this family. The siblings with SRD had more symmetry of cortical thickness in the transverse temporal and superior temporal gyri, while the TD sibling had greater rightward asymmetry. The TD sibling had a greater leftward asymmetry of grey matter volume and cortical surface area in the fusiform, supramarginal, and transverse temporal gyrus. This exploratory study demonstrated that reading-related risk factors appeared to correspond with SRD within this family, suggesting that early examination of biological factors may benefit early identification. Future studies may benefit from the use of polygenic risk scores or machine learning to better understand SRD risk.
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Zhu K, Liu Q, Xie X, Jiang Q, Feng Y, Xiao P, Wu X, Song R. The combined effect between BDNF genetic polymorphisms and exposure to metals on the risk of Chinese dyslexia. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119640. [PMID: 35718045 DOI: 10.1016/j.envpol.2022.119640] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/05/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
BDNF gene has been implicated in the development of cognition and language. Meanwhile, exposure to metals might interact with BDNF gene to increase the risk of neurodevelopmental disorders. The present study aimed to explore the association between BDNF genetic polymorphisms and dyslexic risk and examine whether BDNF polymorphisms would interact with metal exposures, jointly contributing to dyslexia. Among a case-control study composed of 238 children with dyslexia and 228 healthy controls, the BDNF genetic polymorphisms were genotyped by the Sequenom MassARRAY system, and the exposure to eight metals, such as lead (Pb), mercury (Hg) and copper (Cu), were measured using an inductively coupled plasma-mass spectrometer (ICP-MS). Multivariable logistic regression models were used to assess the adjusted odds ratios (ORs) and 95% confidence interval (CI) of dyslexia. After multivariate adjustment, significant associations of dyslexic risk with rs6265 polymorphisms of the BDNF gene were observed (OR = 1.99; 95% CI: 1.15-3.44). Furthermore, exposure to Cu could interact with rs6265 to increase the risk of dyslexia (P interaction = 0.045). High-Cu children with the rs6265 TT genotype were more likely to have dyslexia compared with low-Cu children carrying CC + CT genotypes (OR = 3.19; 95% CI: 1.38-7.39). The findings of this study suggested that the polymorphism of rs6265 in BDNF gene could interact with Cu exposure to increase the occurrence of dyslexia.
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Affiliation(s)
- Kaiheng Zhu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Liu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinyan Xie
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Jiang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanan Feng
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Xiao
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoqian Wu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ranran Song
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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The Polygenic Nature and Complex Genetic Architecture of Specific Learning Disorder. Brain Sci 2021; 11:brainsci11050631. [PMID: 34068951 PMCID: PMC8156942 DOI: 10.3390/brainsci11050631] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/16/2022] Open
Abstract
Specific Learning Disorder (SLD) is a multifactorial, neurodevelopmental disorder which may involve persistent difficulties in reading (dyslexia), written expression and/or mathematics. Dyslexia is characterized by difficulties with speed and accuracy of word reading, deficient decoding abilities, and poor spelling. Several studies from different, but complementary, scientific disciplines have investigated possible causal/risk factors for SLD. Biological, neurological, hereditary, cognitive, linguistic-phonological, developmental and environmental factors have been incriminated. Despite worldwide agreement that SLD is highly heritable, its exact biological basis remains elusive. We herein present: (a) an update of studies that have shaped our current knowledge on the disorder’s genetic architecture; (b) a discussion on whether this genetic architecture is ‘unique’ to SLD or, alternatively, whether there is an underlying common genetic background with other neurodevelopmental disorders; and, (c) a brief discussion on whether we are at a position of generating meaningful correlations between genetic findings and anatomical data from neuroimaging studies or specific molecular/cellular pathways. We conclude with open research questions that could drive future research directions.
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Goldfield GS, Cameron JD, Sigal RJ, Kenny GP, Holcik M, Prud'homme D, Guerin E, Alberga AS, D'Angiulli A, Tremblay MS, Mougharbel F, Walsh J. Screen time is independently associated with serum brain-derived neurotrophic factor (BDNF) in youth with obesity. Appl Physiol Nutr Metab 2021; 46:1083-1090. [PMID: 33829867 DOI: 10.1139/apnm-2020-0756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Low levels of brain derived-neurotrophic factor (BDNF) and excessive screen exposure are risk factors for neurocognitive deficits and obesity in youth, but the relationship between screen time and BDNF remains unknown. This study examined whether duration and/or type of sedentary screen time behaviour (TV viewing, video games, recreational computer use) are associated with serum BDNF levels in youth with obesity. The sample consisted of 250 inactive, postpubertal adolescents with obesity (172 females/78 males, aged 15.5 ± 1.4 years) at the baseline assessment of the Healthy Eating, Aerobic, Resistance Training in Youth Study. After controlling for self-reported age, sex, race, parental education, puberty stage, physical activity, and diet, higher total screen exposure was significantly associated with lower serum BDNF levels (β = -0.21, p = 0.002). TV viewing was the only type of screen behaviour that was associated with BDNF levels (β = -0.22, p = 0.001). Higher exposure to traditional forms of screen time was independently associated with lower serum BDNF levels, and this association appears to be driven primarily by TV viewing. Future intervention research is needed to determine whether limiting screen time is an effective way to increase BDNF and associated health benefits in a high-risk population of youth with obesity. Trial Registration: ClinicalTrials.Gov NCT00195858. Novelty: This study is the first to show that recreational screen time is inversely associated with serum BDNF levels. The inverse association between screen time and BDNF is driven primarily by TV viewing, indicating the type of screen might matter.
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Affiliation(s)
- Gary S Goldfield
- Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Jameason D Cameron
- Department of Pharmacy, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Ronald J Sigal
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Department of Medicine, Cardiac Sciences and Community Health Sciences, Cumming School of Medicine, Calgary, AB, Canada
| | - Glen P Kenny
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Martin Holcik
- Department of Health Sciences, Carleton University, Ottawa, ON, Canada
| | - Denis Prud'homme
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.,Institut du Savoir Montfort, Ottawa, ON, Canada
| | - Eva Guerin
- Institut du Savoir Montfort, Ottawa, ON, Canada
| | - Angela S Alberga
- Department of Exercise Science, Concordia University, Montreal, QC, Canada
| | | | - Mark S Tremblay
- Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Fatima Mougharbel
- Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Population Health, University of Ottawa, Ottawa, ON, Canada
| | - Jeremy Walsh
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
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Kershner JR. An Evolutionary Perspective of Dyslexia, Stress, and Brain Network Homeostasis. Front Hum Neurosci 2021; 14:575546. [PMID: 33551772 PMCID: PMC7859477 DOI: 10.3389/fnhum.2020.575546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/18/2020] [Indexed: 12/20/2022] Open
Abstract
Evolution fuels interindividual variability in neuroplasticity, reflected in brain anatomy and functional connectivity of the expanding neocortical regions subserving reading ability. Such variability is orchestrated by an evolutionarily conserved, competitive balance between epigenetic, stress-induced, and cognitive-growth gene expression programs. An evolutionary developmental model of dyslexia, suggests that prenatal and childhood subclinical stress becomes a risk factor for dyslexia when physiological adaptations to stress promoting adaptive fitness, may attenuate neuroplasticity in the brain regions recruited for reading. Stress has the potential to blunt the cognitive-growth functions of the predominantly right hemisphere Ventral and Dorsal attention networks, which are primed with high entropic levels of synaptic plasticity, and are critical for acquiring beginning reading skills. The attentional networks, in collaboration with the stress-responsive Default Mode network, modulate the entrainment and processing of the low frequency auditory oscillations (1-8 Hz) and visuospatial orienting linked etiologically to dyslexia. Thus, dyslexia may result from positive, but costly adaptations to stress system dysregulation: protective measures that reset the stress/growth balance of processing to favor the Default Mode network, compromising development of the attentional networks. Such a normal-variability conceptualization of dyslexia is at odds with the frequent assumption that dyslexia results from a neurological abnormality. To put the normal-variability model in the broader perspective of the state of the field, a traditional evolutionary account of dyslexia is presented to stimulate discussion of the scientific merits of the two approaches.
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Affiliation(s)
- John R. Kershner
- Department of Applied Psychology, University of Toronto, Toronto, ON, Canada
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Mascheretti S, Riva V, Feng B, Trezzi V, Andreola C, Giorda R, Villa M, Dionne G, Gori S, Marino C, Facoetti A. The Mediation Role of Dynamic Multisensory Processing Using Molecular Genetic Data in Dyslexia. Brain Sci 2020; 10:brainsci10120993. [PMID: 33339203 PMCID: PMC7765588 DOI: 10.3390/brainsci10120993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 12/21/2022] Open
Abstract
Although substantial heritability has been reported and candidate genes have been identified, we are far from understanding the etiopathogenetic pathways underlying developmental dyslexia (DD). Reading-related endophenotypes (EPs) have been established. Until now it was unknown whether they mediated the pathway from gene to reading (dis)ability. Thus, in a sample of 223 siblings from nuclear families with DD and 79 unrelated typical readers, we tested four EPs (i.e., rapid auditory processing, rapid automatized naming, multisensory nonspatial attention and visual motion processing) and 20 markers spanning five DD-candidate genes (i.e., DYX1C1, DCDC2, KIAA0319, ROBO1 and GRIN2B) using a multiple-predictor/multiple-mediator framework. Our results show that rapid auditory and visual motion processing are mediators in the pathway from ROBO1-rs9853895 to reading. Specifically, the T/T genotype group predicts impairments in rapid auditory and visual motion processing which, in turn, predict poorer reading skills. Our results suggest that ROBO1 is related to reading via multisensory temporal processing. These findings support the use of EPs as an effective approach to disentangling the complex pathways between candidate genes and behavior.
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Affiliation(s)
- Sara Mascheretti
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (S.M.); (V.R.); (V.T.); (C.A.)
| | - Valentina Riva
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (S.M.); (V.R.); (V.T.); (C.A.)
| | - Bei Feng
- École de Psychologie, Laval University, Québec, QC G1V 0A6, Canada; (B.F.); (G.D.)
| | - Vittoria Trezzi
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (S.M.); (V.R.); (V.T.); (C.A.)
| | - Chiara Andreola
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (S.M.); (V.R.); (V.T.); (C.A.)
- Laboratoire de Psychologie du Développement et de l’Éducation de l’Enfant (LaPsyDÉ), Universitè de Paris, 75005 Paris, France
| | - Roberto Giorda
- Molecular Biology Laboratory, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (R.G.); (M.V.)
| | - Marco Villa
- Molecular Biology Laboratory, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (R.G.); (M.V.)
| | - Ginette Dionne
- École de Psychologie, Laval University, Québec, QC G1V 0A6, Canada; (B.F.); (G.D.)
| | - Simone Gori
- Department of Human and Social Sciences, University of Bergamo, 24100 Bergamo, Italy;
| | - Cecilia Marino
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy; (S.M.); (V.R.); (V.T.); (C.A.)
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada
- The Division of Child and Youth Psychiatry, Centre for Addiction and Mental Health (CAMH), Toronto, ON M6J 1H4, Canada
- Correspondence: (C.M.); (A.F.)
| | - Andrea Facoetti
- Developmental Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, 35131 Padua, Italy
- Correspondence: (C.M.); (A.F.)
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