An Overview of the Basic Genetic, Epigenetic, and Environmental Factors Relevant to ASD

Background: The autism spectrum disorders are behaviorally defined neurodevelopmental disorders. The association of autism with certain genetic conditions such as Fragile X syndrome, and the increased risk of medical complications such as epilepsy, has been known for some time. Over the past two decades there has been increased awareness of other medical conditions frequently occurring in individuals with autism. 

Objectives: The objective of this presentation is to describe these medical conditions along with an update on recommendations for genetic evaluation in these cases. Participants in the seminar will be able to identify medical conditions and genetic syndromes that have been associated with autism spectrum disorder symptoms. They will also learn which labs to order to screen for medical conditions commonly associated with ASD.

Methods: The genetic factors involved in autism spectrum disorders are complex and poorly understood. Some genetic disorders (Fragile X syndrome, tuberous sclerosis) have been known to have a high incidence of autism. Newer technologies such as chromosomal microarrays have identified additional genetic disorders associated with autism. In addition, certain physical findings may suggest genetic conditions to be ruled out or in, as their presence may lead to close monitoring (e.g., macrocephaly is a common finding in PTEN hamartoma/tumor syndrome; these patients should be monitored for development of tumors) or concomitant treatment.

As research on genetic underpinnings of ASD continues, there is increased attention to potential epigenetic and environmental factors. In recent years multiple factors have been proposed to have an association to ASD, including prenatal (maternal fever, valproic acid exposure), perinatal (caesarean section), and postnatal (bisphenol, high precipitation). Strength of evidence for these and others will be discussed.

The material will be presented through lecture with slides, and a discussion period will follow. 

Results: Participants will increase awareness of genetic conditions commonly associated with autism disorders, and acquire knowledge of currently recommended genetic testing in this population. They will also learn which labs to order to screen for medical conditions commonly associated with ASD. They will become knowledgeable of the environmental exposures that have been found to be associated with diagnosis of ASD. 

Conclusions: Participants will increase knowledge of genetic, epigenetic and environmental factors and be better able to collaborate with other disciplines in evaluation and management of individuals with ASD.