18 June 2007

Gene defect affects millions of asthma sufferers

Researchers at the University of Dundee, who last year identified the gene that causes eczema and associated forms of asthma, have now discovered that defects on the same gene can drastically affect the day-to-day management of asthma in millions of children and young adults.

Their findings apply to about 1 in 4 of all asthma patients, who show a particular gene defect. The most seriously affected sufferers are those with a defect on both copies of the gene, which occurs in only about 1 in 100 asthma patients.

The genetic defect can make asthma sufferers three to six times more likely to have to reach out for their inhaler every day.

The Dundee team announced last year that they had identified a gene that produces the protein filaggrin, which is normally found in large quantities in the outermost layers of the skin and is essential in providing a protective layer which keeps water in and foreign organisms out.

In people with filaggrin mutations, foreign substances can easily enter the skin and be seen by the immune system. This explains the development of inflamed skin (eczema). In some people, priming of the immune system through the "leaky" skin can lead to asthma when foreign substances later enter the lungs.

Since making their initial discovery the Dundee researchers have continued their work on identifying how the filaggrin gene works and the effects its behaviour has.

Now the team of asthma physician Dr. Somnath Mukhopadhyay, scientist Dr. Colin Palmer and genetic skin disease expert Professor Irwin McLean has identified how the gene can determine the amount of treatment that a child or young adult with asthma needs on a day-to-day basis.

In a new paper published in The Journal of Allergy and Clinical Immunology, they show defects in the gene can make asthma patients three to six times more likely to have to reach out for their inhaler every day. These patients are similarly more likely to need extra medicines on top of inhaled steroids to control their asthma.

"Our findings show that these gene defects that affect the skin barrier which filaggrin provides has a significant effect on day-to-day asthma morbidity and medication use," said Dr Mukhopadhyay.

"If these genetic skin barrier defects directly exacerbate asthma, young asthma sufferers who show these barrier defects may respond better to allergen withdrawal strategies, which would lead to a significant long-term reduction in asthma medication requirements."

The need for controller and reliever medicines drives the lifestyles of millions of young asthmatics in the UK and abroad, many of whom have to use their `blue inhaler’, the commonest ‘reliever’ asthma medicine, combined with top-up ‘controller’ asthma treatments.

Eczema and asthma are common and serious diseases in children and young adults in the United Kingdom.

The research was made possible through the support of child patients with asthma in Tayside and their parents, and the support offered by the general practitioners from Dundee, Perth and Kinross, Angus and Fife.

The clinical work in Scotland was supported by the Scottish Executive through Scottish Enterprise Tayside, The Gannochy Trust in Perth and Perth and Kinross Council. The laboratory work was funded by The Wellcome Trust and the skin disease charities DEBRA, PC Project, British Skin Foundation and National Eczema Society.

The paper in the Journal of Allergy and Clinical Immunology can be viewed online at http://www.jacionline.org/article/PIIS0091674907006483/

NOTES TO EDITORS

* 300 Million people worldwide have asthma, and this is expected to increase by a further 100 million by 2025

* Scotland has the highest prevalence rates in the world for childhood asthma symptoms. In adults, Scotland is 3rd highest

* One in twelve adults in Scotland have asthma, which means 390,000 are currently receiving treatment

* 95% of adult asthmatics have symptoms that could be better controlled

The University of Dundee has powered its way to an internationally recognised position of excellence in medical research and life sciences particular expertise in cancer, diabetes, cardiovascular health and tropical diseases. The University hosts The Asthma and Allergy Research Group, a group of experts in the fields of asthma, allergic rhinitis and hayfever, all pursuing research into both childhood and adult asthma and allergies. www.dundee.ac.uk

The Wellcome Trust is the largest charity in the UK. It funds innovative biomedical research, in the UK and internationally, spending around £500 million each year to support the brightest scientists with the best ideas. The Wellcome Trust supports public debate about biomedical research and its impact on health and wellbeing. http://www.wellcome.ac.uk

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