A groundbreaking study by researchers at the Max Planck Institute for Psycholinguistics has uncovered new insights into how genetic variants associated with dyslexia affect brain structure and function.
The research team, led by Sourena Soheili-Nezhad, analyzed genetic data from over one million individuals through 23andMe, combined with brain scans of more than 30,000 adults from the UK Biobank. Their findings reveal that genetic variants linked to dyslexia correlate with structural differences in specific brain regions.
The study showed that people with higher genetic predisposition to dyslexia typically had lower volume in brain areas responsible for movement coordination and speech sound processing. Intriguingly, these same individuals showed increased volume in the visual cortex.
A key finding centered on the internal capsule, a white matter pathway deep within the brain. This region showed connections not only to dyslexia-related genes but also to genetic factors influencing educational achievement, intelligence, and ADHD.
"Dyslexia cannot be explained by changes in a single brain region or gene," notes Soheili-Nezhad. "It's a complex trait involving multiple cognitive functions."
Senior author Clyde Francks suggests some brain differences may develop early in life, possibly during fetal development or infancy, while others might result from long-term behavioral adaptations, such as avoiding reading activities.
The research team plans to extend their investigation to children and adolescents to better understand which brain changes cause dyslexia versus those that develop as a consequence of the condition. This knowledge could potentially lead to earlier diagnosis and more personalized educational interventions for children with dyslexia.
This research marks a major step forward in understanding how genetic factors influence brain development in dyslexia, affecting approximately 5% of school-age children worldwide.