Thursday, August 09, 2007

Autism(s) and Toxicogenomics

How To Read Genes

What looks like a simple light board, above, is actually a DNA microarray, and what you see here is a visual representation of genes responding to a chemical. Scientists know how a chemical affects gene activity in a cell by comparing the genes in exposed cells to those in unexposed cells. Each dot represents one gene. Red dots indicate genes that were more active in the exposed cells, green dots indicate genes that were less active, and yellow dots indicate genes that were equally active in both exposed and unexposed cells.

- Looking Deep, Deep Into Your Genes, NRDC, onearth, Summer 2007

Autisms not autism? References to autisms rather than autism may become much more frequent as the field of toxicogenomics provides more insight into autism and other disorders and diseases.

Laura Wright, senior editor at OnEarth has written an interesting article, Looking Deep, Deep Into Your Genes , which reports on some of the important research developments, such as the Human Genome Project and the Autism Birth Cohort, which are impacting how we understand autism and its causes, or as the article suggests, autisms and their causes. She provides a very readable description of the research into the complex interactions between genes and environment that may ultimately explain and provide treatments for many of the current illnesses and disorders which are on the rise including autism. The research brings into focus the need to look at the tiny genetic differences that make one person or group of persons more vulnerable to different environmental exposures. For example, some children with a certain genetic variant, living in high traffic areas, have been found to be more susceptible to develolping leukemia from exposure to benzene compounds in the auto exhaust. Our understanding of autism, in particular, is beginning to change dramatically:

Do we even understand what today's chronic diseases are? It is beginning to appear that what we call autism may in fact be many illnesses that we've lumped together because those who are afflicted seem to behave similarly. Doctors base their diagnosis on behavioral symptoms, not on what caused those symptoms. Some scientists now refer to the condition as "autisms," acknowledging that we've yet to find a single, unifying biological mechanism, despite the identification, in some studies, of a handful of genes that may confer increased vulnerability. But then, genes or environmental exposures that appear to be important causal factors in one study may not show up at all in another. This leaves scientists to wonder whether the problem isn't that the disease is so diverse in its biological origins that only a truly massive study -- involving many thousands of patients -- would have the statistical power to tease apart the various factors involved.

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