Smoking causes fetal DNA change

LOS ANGELES, May 18 (UPI) -- Children whose mothers smoked during pregnancy are at increased risk of asthma in childhood because of DNA changes, U.S. researchers say.

Carrie Breton, assistant professor of preventive medicine at The Keck School of Medicine of the University of Southern California, Los Angeles, says DNA methylation is a process that can alter a gene's usual function and these altered genes are passed along from parent to child.

The researchers observed DNA methylation-related changes in the AXL gene -- which plays a role in human cancers and in immune response -- in children exposed to maternal smoking in utero.

"We found that children exposed to maternal smoking in utero had a 2.3 percent increase in DNA methylation in AXL," Breton says in a statement. "These results confirm results from a prior study and present compelling evidence that environmental exposure to tobacco smoke during pregnancy may alter DNA methylation levels."