Biological Understanding of Neurodevelopmental Disorders Based on Epigenetics, a New Genetic Concept in Education

Neurodevelopmental disorders, such as autism spectrum disorder, attention deficit hyperactive disorder, and learning disabilities, are heterogeneous conditions that are thought to have a multifactorial etiology including congenital genetic abnormalities and acquired environmental factors. Epigenetics is a biological mechanism that controls gene expression based on chemical modifications of DNA and chromosomal histone proteins. Environmental factors, such as severe mental stress, have been demonstrated to alter gene expression by changing epigenetic chemical modifications in the brain. Therefore, epigenetics is not only involved in congenital autism spectrum disorder-like conditions (e.g., Prader-Willi syndrome and Rett syndrome) but may also be involved in acquired attention deficit hyperactive disorder-like conditions (e.g., via child abuse and neglect). In this chapter, we introduce the basis of the epigenetic mechanism and the recent biological understanding of neurodevelopmental disorders based on epigenetics, which is a new genetic concept not only in medicine but also in education, which bridges internal brain mechanisms and external environmental factors.