Genes and the Environment: New Autism Study

A recent “twin study” from Stanford University is now released in the July 4 online issue of Archives of General Psychiatry. The results of this study highlight that environmental factors play a larger role than previously shown in earlier studies.

Researchers from Stanford University looked at 192 pairs of twins, including 54 pair of identical twins (they share all genes) and 138 pairs of fraternal twins (who share half of their genes).and who receive services for developmental disabilities.

About 43 percent of the identical twins both had autism. About 12.9 percent of the male-male fraternal twins and 20 percent of the female-female fraternal twins both had autism, researchers said.

It’s not surprising that the identical twins were more likely to each have autism, since they share all the same genes, explained lead study author Dr. Joachim Hallmayer, an associate professor of psychiatry and behavioral science at Stanford University. Research has suggested that genetics play a role in the development of autism.

Nevertheless, if a disorder was 100 percent due to genetics, both siblings in each pair of identical twins would have it, which is not the case with autism.

Even though I think this an an important piece, I almost hesitated to post this, and to link to the US News and World Report article because of a handful or reasons.

For one, for many people affected by autism this is obviously an emotionally charged area. Scientists and professionals are not immune either to hyperbole and academic territorialism. Look at the controversy created for many years regarding mercury and vaccines.

Another cautionary note: Depending on which interpretation and article and from which publication, you get a differently slanted headline.

For example” From the US News and World Report: ” Environment May Be Especially Key to Autism: Study.”

From the LA Times: “Autism study downplays role of genetics?.”

Personally i think this is all important and we need to keep investigating but I get a bit nervous knowing how quickly people latch onto the headlines without looking at the study itself. I understand that’s a difficult challenge. Most people don’t know how to, and/or lack the time or access. Studies like these are important, but this is not an overly large sampling, and further studies are crucial to tease this one apart and to dig even deeper. Our society is too quick to react to the headlines and tends to go from one extreme and then the other, like on a pendulum swing.

One part of what was illustrated as “environmental” was certain kinds of anti-depressant medications taken during pregnancy. Should we look with caution regarding these meds during pregnancy? Absolutely. Should pregnant woman stop there meds tomorrow? Not a good idea.

Plus, the statistics can be misleading. As mentioned by Dr. Gary Goldstein, president and CEO of the Kennedy Krieger Institute in Baltimore, “… a close look at the statistics shows they might not be as powerful as it seems. The statistics have a wide “confidence interval,” or range of uncertainty. For the genetic influence on autism, for example, the confidence interval was 9 percent to 81 percent — meaning there’s a chance that the actual number could fall anywhere in that range.”

A promising strand of research in medicine in general that I believe applies here,l is in the interplay and relationships between genetics and environment.

About Sanford

Learning Disabilities specialist and Educational Consultant
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