From: FierceBiotech Research, July 5, 2011
Autism experts skeptical of study linking disorder to environment
By Howard Lovy
Out of all the news organizations that covered the latest study on autism--this one linking it to environmental rather than purely genetic factors--the Los Angeles Times is one of the few to include extreme skepticism from other autism experts about the study's conclusions.
Here's what was found. First, the autism advocacy organization Autism Speaks--which is already predisposed to finding environmental factors in autism's cause--partially funded the research, appearing in the journal Archives of General Psychiatry. The study suggests genetic factors account for 38 percent of the risk associated with autism spectrum disorders, while environmental factors during pregnancy and perhaps early infancy account for 58 percent of the risk. The research was based on a study of 192 pairs of twins, both identical and non-identical, where at least one of the twins in the pair had autism. The conclusions fly in the face of decades of previous research that said genetic inheritance is the biggest factor in determining a child's risk of autism.
The LA Times points out that their calculations are subject to a wide margin of error and could be wrong, but the conclusions point to more research into environmental factors that may contribute to autism, including environmental toxins and chemicals--not coincidentally also factors that Autism Speaks had already concluded contribute to autism's cause before the recent study was performed.
"I think they're really on shaky ground to say that," Dr. Paul Law, director of the Interactive Autism Network at the Kennedy Krieger Institute in Baltimore, told the Times.
"Their data is so similar to everybody else's, and yet they come up with another conclusion," added Robert Plomin, a behavioral geneticist at King's College London. "I don't know how this happened."
Despite this study, most autism experts believe that there is no one "smoking gun," and that a number of smaller factors contribute to a child developing autism spectrum disorders. One of those smaller factors appears elsewhere in the same psychiatric journal. It found that women who took antidepressants anytime during the year before delivery, her child's risk of autism doubled. During the first trimester, the risk tripled. Here, though, researchers cautioned not to jump to too many conclusions based on this first-ever study linking antidepressants to autism. All it means, the researchers say, is that more studies need to be done to rule out other factors.