Genetic background of dyslexia and dysgraphy in children

Abstract

The review is devoted to one of the current problems of pediatric neurology - reading and writing disorders in children as part of a partial developmental disorder. With the development of neuroscience, the paradigm of «brain damage» in the understanding of a number of pathological conditions was replaced by the concept of «evolutionary neurology». The dominance of the ontogenetic approach caused the appearance of a new section in ICD-11 - «Neurodevelopmental disorders». Twenty-one genes associated with the acquisition of reading and writing skills have been identified. Modern studies demonstrate the connection of neuropsychological prerequisites for reading and writing, and clinical phenotypes of dyslexia with changes in specific loci. It is assumed that there are different molecular genetic bases for dyslexia and dysgraphia depending on ethnicity, orthographic features of language, including logographic features. Pleiotropy of genes is a cause of comorbidity of reading and writing disorders with attention deficit and hyperactivity disorder, specific speech articulation disorders, and dyscalculia. A key function of many of the identified genes is their involvement in the processes of neurogenesis. Their dysfunctions cause atypical neuronal migration, ectopic formation, inadequate axonal growth, and dendrite branching at the early stage of brain development. Morphological changes can distort the correct distribution and/or integration of linguistic stimuli in critical brain areas, leading to abnormalities in phonology, semantics, spelling, and general reading comprehension. The knowledge gained can form the basis for the development of risk models for dysgraphia and dyslexia formation and be used as a diagnostic and/or screening tool, which is important for evidence-based correction, optimization of academic performance, and mitigation of psychosocial consequences.