The discovery of this gene is an important advance in our understanding of the genetic causes of asthma

Professor Stephen Holgate, University of Southampton

Asthma affects 3.4 million people in the UK alone and is the most common chronic childhood disease.

Latest estimates suggest that one in seven children under 15 have asthma symptoms which need medical treatment.

Information analysed

Professor Stephen Holgate, who led the Southampton research said the multi-million project had provided valuable information.

"The discovery of this gene is an important advance in our understanding of the genetic causes of asthma.

"In the 25 years since I have been doing asthma research this is the biggest discovery that's been made. It's going to change the whole way we look at the disease," he said.

More than 300 families of asthma sufferers from the South Coast volunteered to take part in the project and were screened for the gene.

They gave extensive clinical information and DNA samples, which were then analysed.

The scientists found five potential candidates for the gene.

Professor Holgate said he was amazed the gene had been so prominent.

"This gene was very, very strongly linked to asthma - like a million to one.

"That was a big surprise. Usually with a complex disease there are so many genes with a small contribution, but this is a major gene. It could account for 40% of clinical presentations (cases of asthma).

"Because it accounts for 40% of clinical expression of asthma it could be used for a powerful screening test in children," he added.

The British results were then linked with the results of a study of 110 American families.

For the project Southampton University teamed up with the Genome Therapeutics Corporation, of Massachusetts and the Schering Plough Corporation.

Professor Holgate and his team are now looking at what role the gene has in the development of asthma.

A spokeswoman for the National Asthma Campaign said they welcomed the research.

"Knowing about these genes is useful because it provides information about the disease and new targets for drugs," she said.