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International Journal of Genomics
Volume 2017 (2017), Article ID 7526592, 23 pages
https://doi.org/10.1155/2017/7526592
Review Article

Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan

Correspondence should be addressed to Kunio Miyake; pj.ca.ihsanamay@ekayimk

Received 21 February 2017; Accepted 2 April 2017; Published 8 May 2017

Academic Editor: Saivageethi Nuthikattu

Copyright © 2017 Nguyen Quoc Vuong Tran and Kunio Miyake This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD), calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD) hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates), persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment.