Genetic change raises risk of childhood asthma: study
By Michael Kahn 1 hour, 18 minutes ago
LONDON (Reuters) - Scientists have identified a genetic change that raises a child's risk of developing asthma, a discovery that may lead to better treatments for one of the most common chronic childhood ailments.
The finding adds to further evidence of the role genetics -- rather than environmental factors such as allergies -- play in how children develop asthma, said William Cookson, a researcher at London's Imperial College's National Heart and Lung Institute, who coordinated the multinational study.
"We often think about asthma in terms of allergies," Cookson said in a telephone interview. "This gene doesn't affect allergies. It suggests other things besides allergies are driving the disease process."
Asthma is an inflammatory disease causing wheezing, coughing and labored breathing that can be life threatening. In some countries as many as 30 percent of children develop the condition, according to the World Health Organization.
Scientists do not exactly know why some children develop asthma, although some believe that allergies can trigger the disease that causes a narrowing of the bronchial tubes.
Treatments include daily inhaled steroid therapy to keep mild-to-moderate cases at bay but Cookson said his team's research could potentially lead to more targeted drugs.
Cookson and colleagues from France, Germany, the United States and Austria, used a new technique to identify genes that predispose children to the disease.
Writing in the journal nature on Wednesday, they said they tested differences in DNA of about 1,000 children with asthma and about 1,200 without and found the big difference between them was on chromosome 17, Cookson said.
Genetic variations on chromosome 17 increased the expression, or activity, of a gene called ORMDL3 in the blood cells of children with asthma, raising the risk of developing the disease by 60 percent.
"We were able to look at genome specimen in the blood of some children and we found that the level of a particular gene ORMDL3 was increased in the blood cells of children with asthma," Cookson said.
"It opens the way for possible new treatments," said Cookson. "The gene could be a target for drugs."
Cookson noted previous studies have found links between genetics and asthma but said this research provides some of the strongest evidence yet of how genetic factors cause the condition in children.
"It is a complex picture," he said. "This isn't the whole picture but it is a major step forward."