An Autism Speaks environmental sciences grant provided support for a symposium on autism at the 49th annual Society of Teratology meeting held on June 29, 2009. Teratology is the branch of biology concerned with how the developing fetus is affected by environmental agents, among other topics.
The theme of this year's meeting was "genetic and environmental interactions on maternal and child health," with more than 250 toxicologists from industries, academia and governmental agencies in attendance. Although scientists in this area have long appreciated that certain compounds administered prior to or during pregnancy can have long-term detrimental consequences, this was the first time autism was highlighted at this very influential meeting.
The first of the three talks in the autism symposium was given by Craig Newschaffer, Ph.D., Director of Epidemiology at Drexel University and member of Autism Speaks' Scientific Advisory Committee. Dr. Newschaffer and his collaborators have recently launched the first large-scale autism study to focus on prenatal exposures and how they interact with genetic factors. For those in the audience not familiar with autism, Dr. Newschaffer provided an overview of the disorder, the spectrum of impairments and potential number of causes, and potential strategies to study the increased prevalence. He also explained the complicated screening and diagnostic tools required for autism research, stressing that both observational and interview tools are needed to accurately diagnose it.
Many environmental risk factors for autism, such as thalidomide, misoprostol, rubella, valproic acid, obstetric complications, and paternal age, have been identified through small clinical studies. Dr. Newschaffer cautioned that if and how these cause autism has not yet been worked out. Acknowledging the lack of published data on genetic and environmental interactions in the field, he noted this was a huge research need. Such studies will require very large numbers of subjects and need to utilize a "case-control" study design. Examples include planned registry studies being set up in Norway, the National Children's Study in the United States, and Dr. Newschaffer's EARLI study (www.earlistudy.org).
The next presentation was provided by Ed Trevathan, M.D., M.P.H., Director of the National Centers on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention. He stressed that while there were core symptoms of autism, these may differ from child to child, and other traits not included in the diagnostic manual for autism may also be useful to characterize it. As a way to visually illustrate symptoms of autism, he utilized Autism Speaks' Autism Video Glossary. He provided examples of approaches that teratologists might use to study the genetic and environmental influences in autism symptom variability. Dr. Trevathan outlined findings in epigenetics as a target for new autism research opportunities, as DNA methylation changes which are induced by environmental factors can influence gene expression and neurodevelopment.
Finally, Christopher Stodgell, Ph.D., from the University of Rochester School of Medicine and Dentistry, spoke on specific genetic and environmental risk factors for autism. He described several examples of environmental factors that may increase risk to autism, such as the use of the anticonvulsant, valproic acid (VPA). Many studies have lined VPA exposure in preganancy to higher than expected rates of autism in offspring. In rats, VPA causes some neuropathogical changes similar to those seen in human post-mortem tissue. In addition to neuropathological deficits, children exposed to VPA during gestation showed differences in eyeblink conditioning, consistent with cerebellar and brainstem abnormalities. The Stodgell lab is currently studying three "at risk" populations in different parts of the world: children who have been exposed to anticonvulsants, the prostaglandin misoprostol (which is sometimes used to end pregnancies early), and thalidomide. They will be examining how the exposures affect gene expression and simultaneously replicating the exposures in animal models in order to carry out more in-depth analyses that parallel what they find in their human studies.
Following the presentations, the speakers received many questions, suggestions and comments on the complexity of the disorder. There was also an overwhelming appreciation to the speakers for having presented these issues to meeting attendees. According to Christina Chambers, president of the Society of Teratology "attendees across multiple disciplines provided very positive feedback on the balanced overview presented in this symposium, which covered both the cutting edge research ongoing in this area, as well as the public health implications of this common disorder." Autism Speaks congratulates the Society of Teratology for having received the grant to include autism as a feature in their annual meeting.