NEW EVIDENCE SEEN FOR INTERACTION BETWEEN MAOA GENE, ADVERSITY

A new study replicates earlier findings that children's genes can strongly influence their response to childhood adversity.

In 2002, Avshalom Caspi et al. reported that 85 percent of severely abused children with a low-activity variant of a gene influencing levels of monoamine oxidase A (MAOA) later developed antisocial behavior. In contrast, children who experienced similar abuse but had a high-activity variant of the MAOA gene rarely exhibited antisocial behavior in adulthood.

In the new study, Debra Foley and her colleagues studied 514 male twins between the ages of 8 and 17. The researchers assessed each child's exposure to adversity, as well as whether or not the children exhibited symptoms of conduct disorder.

Low monoamine oxidase A activity significantly increased the risk for conduct disorder, the researchers say, but only in the presence of an adverse childhood environment, Interestingly, in children from good backgrounds, the low-activity variant of the MAOA gene was associated with a lower, not higher, risk of conduct disorder. "This is an important finding," Foley et al. say, "because it suggests that specific genotypes may be associated with increasing or decreasing risks for psychiatric disorder contingent on environmental exposures."

"Childhood adversity, monoamine oxidase A genotype, and risk for conduct disorder," D. L. Foley, L. J. Eaves, B. Wormley, J. L. Silberg, H. H. Maes, J. Kuhn, and B. Riley, Archives of General Psychiatry, Vol. 61, 2004, 738-44. Address: Debra Foley, Dept. of Human Genetics, Virginia Commonwealth University, P.O. Box 980003, Richmond, VA 23298-0003.