Figure 1: Conceptual Diagram of Non-Genetic Inheritance of Autism.

The diagram illustrates a general overview of how non-genetic inheritance might occur in a case of autism. As an example, an exposure to a toxicant (e.g., anesthetic gas or EDC, as discussed in this paper) could cause epimutation in the germline (in this example, the pool of spermatogonial stem cells in the male, or the pool of oocytes in the female), at genes related to brain development. This then leads to DNA methylation abnormalities in the mature sperm or ovum. Upon the conception, the pattern is retained, perturbing gene expression and the normal process of brain development in the fetus and young child. The offspring exhibits a phenotype of abnormal neurodevelopment and behaviors. This figure features childhood exposures as an example, but a similar phenomenon may occur in other periods as well.