New child asthma gene foundIncreases risk of asthma
Scientists have identified a new gene involved in childhood asthma, and say the discovery may help lead to new treatments for the common respiratory disease.
Asthma, occurs when the airways – the small tubes that carry air in and out of the lungs become narrowed and inflamed, causing wheezing, coughing, chest tightness and shortness of breath.
Over one million children and four million adults in the UK are currently treated for the condition.
In one of the largest studies of its kind, scientists at the Children's Hospital of Philadelphia compared the genes of 793 children who had persistent asthma with those from 1,988 healthy children.
To date, only one other single gene has been identified which increases someone's chances of developing asthma.
Their results found the same genetic variation on chromosome 17 which had been previously identified, but they also found the asthmatic children had a genetic variation in a gene called DENND1b.
Repeating the research with a group of 2,400 European subjects and controls and further analyses on a group of 3,700 African American children showed the same gene for asthma susceptibility in all groups.
The gene is known to be important in helping regulate cells of the immune system respond to foreign material such as bacteria, viruses and allergens - particles which may trigger an asthma attack.
"We now know that the DENND1B gene and its protein are involved in the release of cytokines, which are signalling molecules that in this case tell the body how it should respond to foreign particles," said Dr. Hakon Hakonarson.
"Many of these particles are well-known triggers of asthma. In asthma, patients have an inappropriate immune response in which they develop airway inflammation and overreaction of the airway muscle cells, referred to as airway hyper-responsiveness.
"The gene mutations in DENND1B appear to lead to overproduction of cytokines that subsequently drive this over-sensitive response in asthma patients. "
Because the gene influences how the immune system reacts to allergens, it could lead to new treatments to specifically target the actions of the gene, said the scientists.
The results are published in today's online New England Journal of Medicine.
This article was published on Thu 24 December 2009
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