Environmental toxins and autism: Is there a connection?

Researchers are rounding up more than the usual suspects as they study possible reasons for the growing numbers of children diagnosed with autism.

Kathryn Ellerbeck and Jill Jacobson are turning their attention to Bisphenol A or BPA, a known environmental toxin used as a plasticizer and present in many household products, including the linings of most canned foods. “Scientists have suspected that environmental toxins may be contributing to the increasing number of children with ASD,” Jacobson said.

In earlier work they found that white blood cells from patients with autism display an “upregluation” or turning on of two genes involved in cellular signaling, called GNAS and GNAQ. These two genes encode for G proteins, which send signals from the outside of the cell to the inside.

Many of the hormones that control puberty signal through these G proteins. “At the same time that we are seeing increasing numbers of children being diagnosed with ASD, we are also seeing increasing numbers of children who display early puberty,” Jacobson said.

Both genes were turned on in the brain cells of mice exposed to BPA in tissue culture dishes.

What's more, it appears that BPA exposure can alter the DNA structure of genes and can affect the next generation: Ellerbeck and Jacobsen found that when pregnant mice were exposed to BPA, GNAQ was turned on in organs involved in puberty in mice pups–specifically, the pituitary gland and ovaries.

What's next: The researchers are exploring whether BPA exerts actions not on just a handful of genes but more globally.

Their pilot project was supported by a K-CART Discovery Grant in 2008.

Ellerbeck is a developmental-behavioral pediatrician at the Center for Child Health and Development at the KU Medical Center. Jacobson is a professor of pediatrics/endocrinology at the University of Missouri-Kansas City School of Medicine.

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