Three Dyslexia Susceptibility Genes, DYX1C1, DCDC2, and KIAA0319, Affect Temporo-Parietal White Matter Structure

Background: Volume and integrity of white matter correlate with reading ability, but the underlying factors contributing to this variability are unknown. Methods: We investigated single nucleotide polymorphisms in three genes previously associated with dyslexia and implicated in neuronal migration (DYX1C1, DCDC2, KIAA0319) and white matter volume in a cohort of 76 children and young adults from the general population. Results: We found that all three genes contained polymorphisms that were significantly associated with white matter volume in the left temporo-parietal region and that white matter volume influenced reading ability. Conclusions: The identified region contained white matter pathways connecting the middle temporal gyrus with the inferior parietal lobe. The finding links previous neuroimaging and genetic results and proposes a mechanism underlying variability in reading ability in both normal and impaired readers.