Gene Discovery Sheds Light on Children's Asthma

ByABC News
December 23, 2009, 10:23 PM

Dec. 24 -- WEDNESDAY, Dec. 23 (HealthDay News) -- A new gene involved in immune system function has been linked to moderate-to-severe childhood asthma.

Identification of the specific mutation may one day lead to new targets for treating the widespread and troublesome illness, researchers report in the Jan. 7 issue of the New England Journal of Medicine.

Still, any one gene is likely just a piece of the asthma puzzle, one expert cautioned.

"There are only a handful diseases for which the problem is a single gene, for example, cystic fibrosis. And even those are complex with numerous mutations on that gene," said Dr. Norman Edelman, chief medical officer for the American Lung Association. "Asthma clearly is not a single gene problem. This is good work. They know what the gene codes for but it doesn't mean we're any closer to a cure."

Asthma can likely be attributed to environmental and genetic factors and an interaction between the two, but most of the genes implicated in asthma are still unknown.

One 2007 study used genome-wide association methods to identify ORMLD3 on chromosome 17, the only other gene so far related to asthma risk.

"That gene did not have a hugely significant effect," noted Dr. Hakon Hakonarson, director of the Center for Applied Genomics at Children's Hospital of Philadelphia (CHOP) and the senior author of the new study.

That indicates that probably no one gene will account for the lion's share of asthma. "The 2007 paper would have seen that if that was the case," Hakonarson said.

These researchers used the same methodology -- a genome-wide association study -- to study the genetics of 793 white children with persistent asthma, all patients at CHOP. The team then compared that data to the genetics of almost 2,000 healthy children.

The group of children with asthma were all young, raising the odds that a gene could be detected (average age about 7). "They might have a stronger genetic component if the disease comes up early," Hakonarson explained.