Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review

Abstract

Developmental disorders of spoken and written language are heterogeneous in nature with impairments observed across various linguistic, cognitive, and sensorimotor domains. These disorders are also associated with characteristic patterns of atypical neural structure and function that are observable early in development, often before formal schooling begins. Established patterns of heritability point toward genetic contributions, and molecular genetics approaches have identified genes that play a role in these disorders. Still, identified genes account for only a limited portion of phenotypic variance in complex developmental disorders, described as the problem of “missing heritability.” The characterization of intermediate phenotypes at the neural level may fill gaps in our understanding of heritability patterns in complex disorders, and the emerging field of neuroimaging genetics offers a promising approach to accomplish this goal. The neuroimaging genetics approach is gaining prevalence in language- and reading-related research as it is well-suited to incorporate behavior, genetics, and neurobiology into coherent etiological models of complex developmental disorders. Here, we review research applying the neuroimaging genetics approach to the study of specific reading disability (SRD) and developmental language disorder (DLD), much of which links genes with known neurodevelopmental function to functional and structural abnormalities in the brain.

Identifying interactive biological pathways associated with reading disability

“…Neuronal migration has been hypothesized to be an underlying biological etiology of reading disability because of the differences in brain structure and function in people with reading disability compared to typical readers (McCandliss & Noble, 2003; Niogi & McCandliss, 2006; Waldie et al., 2017). Our evidence for neuron migration fits in with current research examining the gene–brain–behavior model (Landi & Perdue, 2019). An extension from our study is that it is possible that neuron migration was shared for positive and negative associated genes suggesting that the genetic architecture of reading is shared for reading disability and typical reading which raises new questions about the development of reading.…”

“…Both sets of pathways, brain development and dendrite regulation, interacted with neuron migration furthering the possibility that there is a shared genetic and neurobiological architecture for reading. Additionally, the fact that all of the pathways are associated with brain development furthers the gene–brain–behavior model under investigation (Landi & Perdue, 2019).…”

“…Past research has established a genetic contribution for reading disability (Facoetti, Gori, Vicari, & Menghini, 2019; Gialluisi, Guadalupe, Francks, & Fisher, 2017; Landi & Perdue, 2019; Mascheretti et al., 2017; Paracchini, Diaz, & Stein, 2016; Skeide et al, 2015), starting with evidence that reading disability is highly heritable with estimates between 40 and 60 percent (Wadsworth, DeFries, Olson, & Willcutt, 2007; Willcutt et al, 2011). A substantial body of literature has investigated the complex genetic contributions for reading disability, considering single gene associations, gene–gene interactions, and gene–environment interactions.…”

“…Combined the symptoms of reading disabilities negatively affect academic achievement during school‐age years (Daniel et al., 2006; Helland & Asbjornsen, 2003; Morken & Helland, 2013) and have lifelong impacts, such as reduced job attainment (Beer, Engels, Heerkens, & van der Klink, 2014) and increased risk of psychiatric difficulties (Daniel et al., 2006). Current theories hypothesize that the behavioral differences are the result of the neurological differences which seem to be driven by underlying genetic differences (Landi & Perdue, 2019; Mascheretti et al, 2017). Therefore, understanding the genetic and underlying biological etiologies of reading disability could improve theoretical and clinical models for diagnosing and treating reading disability.…”

From Schools to Scans: A Neuroeducational Approach to Comorbid Math and Reading Disabilities

“…These studies have primarily focused on dyslexia (189)(190)(191)(192), but similar evidence is also emerging for dyscalculia (193)(194)(195) and first evidence has appeared for their comorbidity (132). Although exhaustive review is beyond the scope and space of this paper (for very recent reviews see (193,196), our model and research synthesis is complementary and could be further probed with neuroimaging genetics, specifically, in the pursuit of precise early detection of comorbid reading and math disability well before they emerge in formal educational settings. While genetic profile is insufficient to fully explain a complex condition such as dyslexia-dyscalculia comorbidity, some genetic constellations, or endophenotypes, can clearly help in early diagnosis (197).…”