Is It Really "In the Genes "?
Exploring Genetic Connections to Hyperactivity in Youth

You've often heard it said, "It must be in the genes." But is it really? A Family Studies researcher wants to find out. He is exploring the association between genes found in cheek cells and hyperactivity behavior in children, ages 6-16. His answers may prove whether or not the age old adage is true.

David Rowe, a professor in the Division of Family Studies in the School of Family and Consumer Resources, is researching the relation of childhood hyperactivity and conduct disorder to particular genes. Rowe collaborated with Irwin Waldman, an assistant professor of psychology at Emory University, on a project sponsored by the Harry F. Guggenheim Foundation.

"We are looking at genes that are expressed in the brain," Rowe states. "These genes are most likely to influences behavior disorders."

Craig Stever, research technician, sets up samples to be tested for genetic traits.Rowe is interested in several genes related to the brain chemicals dopamine and serotonin. One gene is the dopamine transporter gene. "The transporter gene carries dopamine back into a cell," Rowe explains. "It has a role in modulating communication among brain cells." He adds that the dopamine transporter gene appears to the "target" of several drugs. One drug of abuse, cocaine, is believed to inhibit the transporter gene.

To begin learning about this gene, Rowe first needed DNA samples from children and their parents. These were not difficult to obtain. Subjects involved in this study took a mouth wash of water, with a dash of sugar added, to donate some of their cheek cells. The mouth wash was spun down in a laboratory to yield the cheek cells, and DNA was then extracted from them.

Many children involved in Rowe's study have been seen in a clinic or by a private psychiatrist for behavior disorders. Other children were control subjects, or those children in the community without known behavior disorders. Most of the 191 children involved were boys, Rowe says.

"We wanted to compare children with and without behavior disorders," Rowe says. "We had DNA from both groups, so the next step was to find out what the genes each had."

To do this, Rowe used PCR (Polymerase Chain Reaction), a method used to amplify genes. The dopamine transporter gene comes in two forms, labeled "10" and "9". PCR reveals which gene a child inherited from his father and mother. A previous study had found that the 10 form of the gene was associated with increased likelihood of hyperactivity. Rowe was able to confirm this discovery.

"If a gene is causing a particular disorder," he says, "you'd expect this gene more often in affected children than in unaffected ones. In our own study, we found that the 'ten' form was more common in children with the symptoms of hyperactivity and conduct disorder than in the control children."

Rowe also looked at parents who had one 10 form and one 9 form. In this circumstance, affected children were more likely to have inherited the 10 form. For control children, the chance of getting one gene or the other was 50:50, the same as a coin flip.

"The aim of my research is to find genes associated with behavior. I regard this work as basic science," he states. "We are just beginning to learn about how genes affect behavior. While the public should not expect miracle therapies from these early discoveries, they may form the basis of new treatments in the future."


Article Written by Crystal Renfrow, ECAT, College of Agriculture
This is part of the 1996 Arizona Experiment Station Research Report
This document is located at http://ag.arizona.edu/pubs/general/resrpt1996/in_the_genes.html
Return to index for 1996 report

Researcher:

David Rowe, Division of Family Studies, School of Family and Consumer Resources Building
dcr091@ccit.arizona.edu