Genetic predisposition increases childhood asthma risk

Aug 21, 2007

Children who carry variations in specific genes that metabolize vehicle emissions are more susceptible to developing asthma, particularly if they live near major roadways, a study led by researchers at the University of Southern California (USC) suggests.

Researchers found that children who carried variations in two genes and lived within 75 meters of a major road were up to nine times more likely to develop asthma than children who lived further away, says Muhammad T. Salam, Ph.D. candidate at the Keck School of Medicine of USC, and the study’s lead author. The study will appear in the journal Thorax, and is now available online.

“This is one of the first studies to report that children with certain genetic backgrounds are even more susceptible to asthma than if they lived near major roads and did not carry the variations,” Salam says. “We are working to understand how traffic-related exposures may interact with these genes, leading to asthma development.”

Asthma is the most common chronic disease in children, and previous studies have shown that traffic-related pollution near the home increases asthma risk and reduces lung growth, according to USC experts.

Researchers drew upon data from the Children’s Health Study (CHS), a longitudinal study of respiratory health among school-age children in 12 Southern California communities. They compared associations between number of genetic variants and exposure to toxins among more than 3,000 study participants.

Researchers found that high levels of microsomal epoxide hydrolase (EPHX1)—an enzyme that metabolizes polyaromatic hydrocarbons (PAH) in vehicle emissions—was associated with an increased risk for lifetime asthma. Children with high EPHX1 levels who also carried variations in glutathione S-transferase P1 (GSTP1) genes were four times more likely to have asthma.

Among children who lived within 75 meters of a major road, those with high EPHX1 activity were three times more likely to have asthma than those with lower activity. Children who carried both variations and lived within 75 meters of a major road were at the highest asthma risk. The results were consistent for current, early and late onset asthma.

"This finding demonstrates the critical role of gene environment interaction in determining disease susceptibility," says David A. Schwartz, M.D., director of the National Institute of Environmental Health Sciences. "The investigators at USC have identified key genetic variations in biological pathways related to PAH metabolism that are associated with the occurrence of asthma in children who live in close proximity to traffic."

Approximately 12 percent of children in the study carried both of the variations and three percent were in the highest risk group based on where they lived. However, there are a number of genes that could be linked with asthma, and researchers are just beginning to study the associations between genes and environmental factors, Salam says.

“It is difficult to say that if parents with an asthmatic child move further from busy streets, the child will definitely have fewer symptoms,” he explains. “All that can be said at this moment is that data from this and other studies show strong evidence that living near heavy traffic increases asthma risks and exacerbates symptoms in children who already have asthma.”

Source: University of Southern California

Explore further: Immunity, signaling genes may be linked to schizophrenia

add to favorites email to friend print save as pdf

Related Stories

How Kindle Unlimited compares with Scribd, Oyster

7 hours ago

Amazon is the latest—and largest—company to offer unlimited e-books for a monthly fee. Here's how Kindle Unlimited, which Amazon announced Friday, compares with rivals Scribd and Oyster.

NASA sees powerful thunderstorms in Tropical Storm Matmo

8 hours ago

Strong thunderstorms reaching toward the top of the troposphere circled Tropical Storm Matmo's center and appeared in a band of thunderstorms on the storm's southwestern quadrant. Infrared imagery from NASA's ...

ISS 'space truck' launch postponed: Arianespace

10 hours ago

The July 24 launch of a robot ship to deliver provisions to the International Space Station has been postponed "for a few days", space transport firm Arianespace said Friday.

Recommended for you

Mysterious esophagus disease is autoimmune after all

16 hours ago

(Medical Xpress)—Achalasia is a rare disease – it affects 1 in 100,000 people – characterized by a loss of nerve cells in the esophageal wall. While its cause remains unknown, a new study by a team of researchers at ...

Diagnostic criteria for Christianson Syndrome

Jul 21, 2014

Because the severe autism-like condition Christianson Syndrome was only first reported in 1999 and some symptoms take more than a decade to appear, families and doctors urgently need fundamental information ...

New technique maps life's effects on our DNA

Jul 20, 2014

Researchers at the BBSRC-funded Babraham Institute, in collaboration with the Wellcome Trust Sanger Institute Single Cell Genomics Centre, have developed a powerful new single-cell technique to help investigate how the environment ...

User comments : 0