Gene by environment interactions influencing reading disability and the inattentive symptom dimension of attention deficit/hyperactivity disorder

Abstract

Background RD and ADHD are comorbid and genetically correlated, especially the inattentive dimension of ADHD (ADHD-I). However, previous research indicates that RD and ADHD enter into opposite gene by environment (GxE) interactions. Methods This study used behavioral genetic methods to replicate these opposite GxE interactions in a sample of same-sex MZ and DZ twin pairs from the Colorado Learning Disabilities Research Center (CLDRC; DeFries et al., 1997) and to test a genetic hypothesis for why these opposite interactions occur. Results We replicated opposite GxE interactions for RD (bioecological) and ADHD-I (diathesis-stress) with parental education in the same sample of participants. The genetic hypothesis for this opposite pattern of interactions is that only genes specific to each disorder enter into these opposite interactions, not the shared genes underlying their comorbidity. To test this hypothesis, we used single models with an exploratory three-way interaction, in which the GxE interactions for each disorder were moderated by comorbidity. Neither three-way interaction was significant. The heritability of RD did not vary as a function of parental education and ADHD-I. Similarly, the heritability of ADHD-I did not vary as a function of parental education and RD. Conclusions We documented opposite GxE interactions in RD and ADHD-I in the same overall twin sample, but the explanation for this apparent paradox remains unclear. Examining specific genes and more specific environmental factors may help resolve the paradox.

Specific Learning Disorders and ADHD: Current Issues in Diagnosis Across Clinical and Educational Settings

“…Additional studies found shared factors related to processing speed and inattention suggesting stronger comorbidity with the predominantly inattentive ADHD type [6,15] as well as working memory [16]. While processing speed was found to be the shared factor at cognitive and genetic levels in many studies, RAN, in particular, also was a potential risk factor as they are both highly correlated [6,17] with reading and attention deficits.…”

Alterações Fonoaudiológicas no Transtorno de Déficit de Atenção e Hiperatividade: revisão sistemática de literatura

“…C PC PC PC C Rosenberg J, Pennington BF, Willcut EG, Olson RK (29) . C PC PC PC C Birkett EE, Talcott JB (30) .…”

“…Analysis of the second thematic axis, concerning studies that used both Speech-language Pathology and Neuropsychology assessments of ADHD, revealed 17 articles (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) , which assessed not only the Speech-language Pathology disorders observed in ADHD, but also the aspects related to neuropsychological performance, through specific tests and scales of evaluation of the disorder. Among the studies included in this theme axis, eight addressed reading difficulties (15,17,18,20,25,(28)(29)(30) ; two dealt with difficulties of math and reading (14,21) ; three had the relation between cerebral structures and the alterations of language as their main focus (16,19,27) ; one addressed neuropsychological performance in the inattentive and combined subtypes (24) ; one evaluated performance in executive and central coherence tasks (22) ; one focused on the perception of time, phonological skills, and executive function in ADHD (26) ; and one investigated fine motor, sensory and perceptual functions (23) .…”

“…Among the studies included in this theme axis, eight addressed reading difficulties (15,17,18,20,25,(28)(29)(30) ; two dealt with difficulties of math and reading (14,21) ; three had the relation between cerebral structures and the alterations of language as their main focus (16,19,27) ; one addressed neuropsychological performance in the inattentive and combined subtypes (24) ; one evaluated performance in executive and central coherence tasks (22) ; one focused on the perception of time, phonological skills, and executive function in ADHD (26) ; and one investigated fine motor, sensory and perceptual functions (23) . Regarding reading difficulties in ADHD, the importance of word recognition and decoding and reading speed for text comprehension was discussed in a study conducted in the United States (15) .…”

“…The genetic risk related to ADHD and reading difficulties was discussed in international studies conducted with twins (28,29) . In one of these studies (28) , the authors referred to research that demonstrated the co-occurrence of both pathologies due to genetic risk factors.…”