Author Interviews, Autism, Genetic Research, JAMA / 27.09.2017
Autism Spectrum Disorder Found To Be Highly Heritable
MedicalResearch.com Interview with:
[caption id="attachment_37175" align="alignleft" width="114"]
D. Sandin[/caption]
Sven Sandin, PhD Assistant Professor
Department of Psychiatry
Icahn School of Medicine at Mount Sinai
New York, NY 10029
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: In 2014, we estimated the heritability of autism to be approximately 50%. Motivating us then was the lack of studies in autism heritability using population based and the findings from a twin-study in California finding the heritability to be substantially lower than the 80-90% estimated in previous studies. Since then continued efforts working with the questions on heritability and environmental factors for autism we found differences between different methods and different samples. When we went back to our previous data we found the heritability of autism to be higher than previously estimated. We found that our previous result was due to a methodological artifact where the adjustment for differences in follow-up used in that manuscript underestimated the heritability. Using methods used in other heritability studies the heritability is now estimated to 84%. Importantly, as previously concluded, there is no support for any ‘shared environmental factors’ in the etiology of autism, e.g. environmental factors shared between two siblings.
D. Sandin[/caption]
Sven Sandin, PhD Assistant Professor
Department of Psychiatry
Icahn School of Medicine at Mount Sinai
New York, NY 10029
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: In 2014, we estimated the heritability of autism to be approximately 50%. Motivating us then was the lack of studies in autism heritability using population based and the findings from a twin-study in California finding the heritability to be substantially lower than the 80-90% estimated in previous studies. Since then continued efforts working with the questions on heritability and environmental factors for autism we found differences between different methods and different samples. When we went back to our previous data we found the heritability of autism to be higher than previously estimated. We found that our previous result was due to a methodological artifact where the adjustment for differences in follow-up used in that manuscript underestimated the heritability. Using methods used in other heritability studies the heritability is now estimated to 84%. Importantly, as previously concluded, there is no support for any ‘shared environmental factors’ in the etiology of autism, e.g. environmental factors shared between two siblings.



















David Beversdorf, M.D.
Associate professor in the departments of radiology, neurology and psychological sciences
University of Missouri and
Missouri University Thompson Center for Autism and Neurodevelopmental Disorders
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Beversdorf: Our previous work had demonstrated in retrospective surveys a higher incidence of prenatal psychosocial stress exposure during the late 2nd and early 3rd trimester in pregnancies where the offspring had developed autism spectrum disorder (ASD). This had been confirmed in other studies, including a study examining the timing of exposure to tropical storms during pregnancy. However, not everyone exposed to stress during pregnancy has a child with ASD, so we began to look at genetic risk for augmented stress reactivity. This initial exploration involved examination of the interaction between stress exposure during ASD-associated pregnancies and the maternal presence of variations in one gene well known to affect stress reactivity. Variations in this gene were also targeted as they have been associated with ASD in some studies. We found in two independent groups of patients (one in Missouri, one in Ontario, Canada) that maternal presence of at least one copy of the stress-susceptible variant of this gene is associated with the link between maternal stress exposure during this time window of pregnancy and subsequent development of ASD in the offspring.
Dr. Steven Hicks[/caption]
Steven Daniel Hicks, M.D., Ph.D.
Penn State Hershey Medical Group Hope Drive, Pediatrics
Hershey, PA 17033
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Hicks: This research was inspired by results of the CHARGE study (examining environmental influences on autism) which showed that specific pesticides (including pyrethroids) increased the risk of autism and developmental delay, particularly when mothers were exposed in the 3rdtrimester.
We recognized that the department of health sprayed pyrethroids from airplanes in a specific area near our regional medical center every summer to combat mosquito borne illnesses. We asked whether children from those areas had increased rates of autism and developmental delay. We found that they were about 25% more likely to be diagnosed with a developmental disorder at our medical center than children from control regions without aerial spraying of pyrethroids.
