March 30, 2009

Genetic variation affects lung function

U.S. researchers say they've determined even a tiny genetic variation can control how quickly and well lungs grow and function in children and adolescents.

And the University of Southern California scientists say it also can determine how susceptible children will be to exposure to second-hand tobacco smoke, even in utero.

We wanted to determine whether specific gene variations would have measurable and predictable effects on lung function growth and susceptibility to environmental insults, said Carrie Breton of the university's Keck School of Medicine, the study's lead author. "We looked at a class of genes known to be involved in anti-oxidant defense, the glutathione-s transferase genes.

Overall, we found variation in several of the GST genes was important. This was particularly true for children of mothers who had smoked during pregnancy, said Breton.

The researchers suggest the gene variants might also alter a lung's ability to defend itself against damage caused by free radicals.

The GST genes are important to the detoxification of reactive oxygen species, including carcinogens and environmental exposures, such as cigarette smoke. We speculate the patterns of genetic variation we investigated may alter this process, thereby reducing the lung's ability to detoxify harmful agents and causing a cascade of other events that promote inflammation, bronchial constriction, airway hyper-responsiveness and asthma-like symptoms, said Breton.

The study appears in the journal Respiratory and Critical Care Medicine.