In the long run, a proper understanding of the causes and effects of developmental dyslexia is likely to be found in the molecules, cells or tissues of the body.
A vital aspect of cells or a group of cells is clearly different in people with dyslexia. For example, when the child is still in the womb the extending axons of the developing nerve cells must make turns and grow along a complex migratory path to their correct destination. KIAA 0319 controls neuronal migration. When the gene for the ‘Robo’ (‘Roundabout’) receptor is not fully expressed in people with dyslexia this may explain ectopias (see ‘Anatomy’) and other abnormal migrations ofmagnocellular neurons, which are essential for the fast timing of movements of the eyes, as in reading and in auditory discrimination. In this example, it is clear in the second image that neurons have not migrated normally to the cortical plate.