Genome scan for cognitive trait loci of dyslexia: Rapid naming and rapid switching of letters, numbers, and colors

Abstract

Dyslexia, or specific reading disability, is a common developmental disorder that affects 5–12% of school-aged children. Dyslexia and its component phenotypes, assessed categorically or quantitatively, have complex genetic bases. The ability to rapidly name letters, numbers, and colors from rows presented visually correlates strongly with reading in multiple languages and is a valid predictor of reading and spelling impairment. Performance on measures of rapid naming and switching, RAN and RAS, is stable throughout elementary school years, with slowed performance persisting in adults who still manifest dyslexia. Targeted analyses of dyslexia candidate regions have included RAN measures, but only one other genome-wide linkage study has been reported. As part of a broad effort to identify genetic contributors to dyslexia, we performed combined oligogenic segregation and linkage analyses of measures of RAN and RAS in a family-based cohort ascertained through probands with dyslexia. We obtained strong evidence for linkage of RAN letters to the DYX3 locus on chromosome 2p and RAN colors to chromosome 10q, but were unable to confirm the chromosome 6p21 linkage detected for a composite measure of RAN colors and objects in the previous genome-wide study.

Does Training in Syllable Recognition Improve Reading Speed? A Computer-Based Trial With Poor Readers From Second and Third Grade

“…Some part of this stability can be explained by genetic sources, as a strong genetic influence has been shown in RAN performance (e.g., Byrne et al, 2006;Christopher et al, 2015;Davis et al, 2001;Petrill, Deater-Deckard, Thompson, DeThorne, & Schatschneider, 2006;Petrill et al, 2010;Samuelsson et al, 2007). There is also recent research evidence for specific genes that have been associated with RAN performance (Naples, Chang, Katz, & Grigorenko, 2009), some of them the same as those previously associated with dyslexia (Rubenstein, Raskind, Berninger, Matsushita, & Wijsman, 2014). In addition, brain imaging studies have recently shed further light on the neural basis of RAN performance, showing that activation during naming tasks is present in the areas involved in attention, and that eye-movement control is also present in the areas usually associated with reading tasks (McCrory, Mechelli, Frith, & Price, 2005;Misra, Katzir, Wolf, & Poldrack, 2004).…”

Differential diagnosis of dysgraphia, dyslexia, and OWL LD: behavioral and neuroimaging evidence

“…For Rapid Automatic Letter Naming RAN (test-retest reliability .90) (Wolf & Denckla, 2005), which is a measure of phonological loop for cross-code integration in language learning (Baddeley et al 1998) and has a genetic basis (Rubenstein, Raskind, Berninger, Matsushita, & Wijsman, 2014), the task is to name lower case printed letters arranged in rows; the. The total score is the time required to name all the letters in all the rows.…”

“…On the one hand, the variations in functional connectivity observed during middle childhood and early adolescence may be due to genetic variants associated with spelling (e.g., Roeske et al, 2009; Rubenstein et al, 2011; Schulte-Kőrne et al, 1998) or endophenotypes for attention supporting language learning (e. g,, Posner and Rothbart, 2007; Rubenstein et al, 2014). On the other hand, the persisting problems may be due to instruction that is not tailored to the changing nature and requirements of the curriculum during middle childhood and adolescence (e.g., see Troia, 2009), which needs to include spelling and go beyond phonology only to orthography and morphology and their interrelationships with each other.…”

Evidence-Based Reading and Writing Assessment for Dyslexia in Adolescents and Young Adults

“…Likewise, prior research demonstrated a genetic basis for some of the working memory predictors: nonword repetition for phonological coding (Wijsman et al, 2000), phonological loop (Rubenstein, Raskind, Berninger, Matsushita, Wijsman, 2014), and switching attention (Rubenstein et al, 2014). For this study of adolescents and young adults with multigenerational family history of dyslexia, however, the focus was on the phenotypes—the behavioral expression—rather than genetic variations—and the potential heterogeneity and developmental change of the phenotypes.…”