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Free keywords:
Developmental dyslexia; Magnetic resonance imaging (MRI); Fusiform gyrus; NRSN1
Abstract:
Developmental dyslexia (DD) is considered to be the most common among all learning disorders. About 5% of the population in Germany and 7% in the USA suffer from the psychological and social consequences of severe deficits in learning how to read and spell. DD arises from the complex interplay of genetic and environmental factors (e. g. home literacy environment). Moreover, numerous previous magnetic resonance imaging (MRI) studies have shown that the left fusiform gyrus (FFG, “visual word form area”) of the brain plays a crucial role in literacy acquisition. The present work suggests that the cortical plasticity of the FFG might be limited in individuals with DD because they carry a risk variant of the gene NRSN1 that codes proteins regulating neurite growth. NRSN1 turned out to be significantly associated with the volume of the left FFG that was estimated by conducting a voxel-based morphometry (VBM) analysis of MR images. Using volumetric profiles determined by genetic association in children, DD could be predicted 10 months before school entry with a classification accuracy of 75%. These data might make it possible in the future to diagnose DD so early that affected children might be able to compensate their deficits before school enrollment by making use of early intervention programs.
