Sluggish Attentional Shifting Seems Genetically Determined in Developmental Dyslexia: Evidence from the Nicotinergic Receptor Alpha 4 Subunit Gene

Developmental dyslexia (DD) or reading acquisition disorder, is a heritable multi-factorial condition. In addition to the typical auditory and phonological deficits that characterize the DD, there is evidence for a sluggish attentional shifting. Since attentional shifting is mainly mediated by the brain nicotinergic system, it is conceivable that the polygenic basis of DD may encompass nicotinergic receptor genes. Here, we addressed whether nicotinergic receptor alpha 4 subunit gene (CHRNA4) variation (i.e., rs3827020 TC/CC vs. TT genotype) influences transient spatial attention in 100 children with DD. The time-course of transient spatial attention was measured by using a spatial cuing paradigm: A peripheral and uninformative cue preceded the onset of a lateralized target stimulus in the same (valid cue) or different (invalid) location. Two different cue-target intervals were employed as well. We found a specific association between transient visual attention and CHRNA4. In particular, TC/CC dyslexics showed a slower time-course of transient spatial attention compared with TT dyslexics. Thus, we provide an evidence that specific genes can be associated with specific phenotypes of the multifaceted neurocognitive impairment of DD.