Today’s News and Observer features research which suggests a tantalizing link between environmental toxicity and autism. In the article, “Could autism and ‘chemo brain’ share similar origin?” researchers at the University of North Carolina-Chapel Hill posit that a “single biological process plays a role in the origin of both autism” and the cognitive deficits that can occur temporarily after rounds of chemotherapy. A common chemotherapy drug suppressed synaptic ability, but the effect of this disruption would likely to be quite different on adults and children. Adults have already formed neural connections and these recover after chemo. But the effect on a developing brain could be quite different. One of the researchers, Mark Zylka, is quoted in the article: “Impairing synaptic function in a developing brain, even for a relatively short period, can lead to long-lasting effects because of how the brain is wired through a series of critical periods. The critical periods are when the brain is most adept at wiring for certain tasks. Once these connections form, the brain moves on and does other things.”
The research reported today is built on previous research which established where the chemo (topotecan) inhibits the formation of a certain protein. The only genes affected are “long” genes and “many of the genes implicated to autism are very long.” Zylka explains that two causes for the significant increase in autism include better identification and environmental factors. “We’re interested in this environmental angle, that chemicals in our environment might perturb brain development and increase the risk for autism.” Zylka and his team are studying herbicides and pesticides to identify those which may interfere with long genes as topotecan does.
I’m encouraged by this line of research. This reminds me of the DDT era, where that toxic substance was routinely sprayed across the country. After environmentalists raised the alarm as certain species of birds of prey and marine animals were dying off, DDT was eventually banned in 1972 (after concerns were first raised in the 1940’s). DDT can take years to break down in the soil and can remain in the human body for 50 years. Yikes. (Yes, DDT has been effective in reducing rates of malaria, but DDT-resistant mosquitoes have also emerged.) If some other form of chemical (or a deadly combination) is wreaking havoc on the developing brains of kids, I hope we can identify and eradicate its use quickly.