Neurobiological systems in dyslexia

Kershner, John R.

doi:10.1016/j.tine.2018.12.001

Cited by 18 publications

(16 citation statements)

References 200 publications

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“…Mascheretti et al (2018) performed a systematic review of studies examining environmental factors for dyslexia and reported birthweight and gestational weeks were predictive of dyslexia status and possible interplay between genetic risk and teacher quality and parental education. Recent research has provided some insights into how genes and environmental factors may interact (Gu et al, 2018; Kershner, 2019; Mascheretti et al., 2018; Mascheretti et al, 2013). Gu et al (2018) examined the interaction between genetic variants in CNTNAP2 and environmental factors and found sex specific interaction; specifically, they found that two variants (rs3779031 and rs987456) in CNTNAP2 were associated with reading disability status in females but not males and that the interaction between rs987456 and scheduled reading time was protective in females.…”

Section: Introductionmentioning

confidence: 99%

Identifying interactive biological pathways associated with reading disability

et al. 2020

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Introduction Past research has suggested that reading disability is a complex disorder involving genetic and environment contributions, as well as gene–gene and gene–environment interaction, but to date little is known about the underlying mechanisms. Method Using the Avon Longitudinal Study of Parents and Children, we assessed the contributions of genetic, demographic, and environmental variables on case–control status using machine learning. We investigated the functional interactions between genes using pathway and network analysis. Results Our results support a systems approach to studying the etiology of reading disability with many genes (e.g., RAPGEF2 , KIAA0319 , DLC1 ) and biological pathways (e.g., neuron migration, positive regulation of dendrite regulation, nervous system development) interacting with each other. We found that single nucleotide variants within genes often had opposite effects and that enriched biological pathways were mediated by neuron migration. We also identified behavioral (i.e., receptive language, nonverbal intelligence, and vocabulary), demographic (i.e., mother's highest education), and environmental (i.e., birthweight) factors that influenced case–control status when accounting for genetic information. Discussion The behavioral and demographic factors were suggested to be protective against reading disability status, while birthweight conveyed risk. We provided supporting evidence that reading disability has a complex biological and environmental etiology and that there may be a shared genetic and neurobiological architecture for reading (dis)ability.

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Section: Introductionmentioning

confidence: 99%

Identifying interactive biological pathways associated with reading disability

et al. 2020

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“…Specifically, gene-gene (GxG/epistasis) and genotype-environment (GxE) interactions could modify the expression of individual genes, further influencing genetic susceptibility and broadening the DD phenotypic spectrum. The observed phenotypic heterogeneity of DD, including its spectrum of phenotypes and endophenotypes, may be further explained by inter-individual variation and genotype-epigenotype interactions [26][27][28]. Table 1 summarizes literature findings that advocate the role of environment in the putative modulation of genetic susceptibility, thus affecting the individual DD risk.…”

Section: Why Gene-only Dd Models Lack Cause-effect Specificity?mentioning

confidence: 99%

“…A plethora of models have been proposed for DD etiopathology, supporting the critical role of the environment [15,26]. Environmental triggers, such as stress, maternal diet, and lifestyle have been proposed as modulators of genetic susceptibility via posttranslational, epigenetic interactions [23,[28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Section: A Role For Stress In the Dd Phenotypementioning

confidence: 99%

Developmental Dyslexia: Environment Matters

et al. 2021

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Developmental dyslexia (DD) is a multifactorial, specific learning disorder. Susceptibility genes have been identified, but there is growing evidence that environmental factors, and especially stress, may act as triggering factors that determine an individual’s risk of developing DD. In DD, as in most complex phenotypes, the presence of a genetic mutation fails to explain the broad phenotypic spectrum observed. Early life stress has been repeatedly associated with the risk of multifactorial disorders, due to its effects on chromatin regulation, gene expression, HPA axis function and its long-term effects on the systemic stress response. Based on recent evidence, we discuss the potential role of stress on DD occurrence, its putative epigenetic effects on the HPA axis of affected individuals, as well as the necessity of early and appropriate intervention, based on the individual stress-associated (endo)phenotype.

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“…However, a valid inference of brain impairment requires evidence of structural, and behaviorally significant abnormalities in neurological organization observed in large studies with representative samples. Finally, the widely recognized candidate genetic variants for dyslexia (i.e., DYXIC1, K1AA0319, DCDC2, ROBO1) may only become risk genes if the time course of their expression is altered by experience, including stressful events, again, a part of normal development (Kershner, 2019).…”

Section: General Model Considerationsmentioning

confidence: 99%

“…Recent theoretical advances in evolutionary developmental biology (Evo-Devo) question the justifiability of applying these assumptions widely to the general population. Evo-Devo models of stress and dyslexia, showing how early stress may lead to costly but adaptive behavioral strategies in the course of growing up, suggest that stress responsivity is not abnormal or strictly dysfunctional (Ellis and Del Giudice, 2019), although stress system dysregulation may result in children struggling to acquire fluent reading skills (Kershner, 2019(Kershner, , 2020a. Such conditional during typical child development contradicts the view sometimes exhibited in research and clinical studies that individuals with dyslexia are suffering from a pathopsysiological condition.…”

Section: Introductionmentioning

confidence: 99%

An Evolutionary Perspective of Dyslexia, Stress, and Brain Network Homeostasis

Kershner

2021

Front. Hum. Neurosci.

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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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Neurobiological systems in dyslexia

Cited by 18 publications

References 200 publications

Identifying interactive biological pathways associated with reading disability

Identifying interactive biological pathways associated with reading disability

Developmental Dyslexia: Environment Matters

An Evolutionary Perspective of Dyslexia, Stress, and Brain Network Homeostasis

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