Genetic advances could lead to new treatments

They have established the impact of one of these genes, called GPRA, though the other remains a mystery.

Other asthma genes have previously been identified, but with a weaker link, Science magazine reported.

The findings could lead to new drugs, but some experts warned progress towards different treatments as a result of genetics was slow.

Around 10% of adults and 15% of children in the UK have asthma. Though rates have risen sharply, there is some evidence that they are now levelling off in the Western world.

The number of genes which may be related to asthma is enormous. We are making progress slowly but surely Dr Hasan Arshad

In the latest study, blood samples of asthmatic and non-asthmatic people in families with some history of the condition were analysed by researchers based at Sweden's Karolinska Institute.

They looked at blood samples from 900 Finnish people and then double checked with DNA from 400 residents of Quebec, Canada.

The Finnish people in the study were chosen because they were relatively geographically isolated and genetically fairly uniform.

Variant

The researchers found there were variant DNA sequences associated with asthma in more than half the asthma patients but just a third of the healthy people.

The findings were then supported by research at McGill University, Canada.

Further comparisons revealed the GPRA gene and the mystery gene AAA1. GPRA produces one of a class of molecules which can be targeted for drug development.

They could not establish what the AAA1 gene does, though they established its link to asthma because of its high level of occurrence in people with the condition.

Study leader Juha Kere, from the Karolinska Institute in Stockholm, said the properties of GPRA made it a "strong candidate" for involvement in asthma as well as being a "possible drug target".

The National Asthma Campaign said: "This is an exciting development. Looking at a genetically pure isolated population has enabled the researchers to identify a gene that appears to have a relatively strong link to asthma.

Responsible

"One of the genes seems to be responsible for a protein in the body that could be a new drug target for anti asthma treatments.

"Building on these initial findings, further research will help us determine whether this gene is likely to be important to most people with asthma."

Dr Hasan Arshad, director of the David Hide Asthma and Allergy Research Centre on the Isle of Wight, welcomed the research but warned progress was piecemeal.

He said: "The number of genes which may be related to asthma is enormous. We are making progress slowly but surely."

However, he added: "There are new drug developments happening all the time but none of them yet are based on the genetic advances.

"Most of the drugs are either aimed at suppression of the immune system or suppression of inflammation."