Behind the headlines: Gene breakthrough for allergies

Researchers have made the first step towards gene therapy for eczema.

WHAT IS THE STORY?

Scientists have discovered the gene responsible for dry, flaky skin, which predisposes sufferers to eczema and asthma, according to media reports.

The newspapers said that some five million people in Britain are carrying the mutated gene and claimed that the breakthrough discovery could pave the way for new treatments.

WHAT IS THE RESEARCH?

These reports are based on the work of researchers at the University of Dundee, with collaborators in Glasgow, Dublin, Seattle and Copenhagen.

They found that two genetic variants in the gene that encodes the protein filaggrin were very strong predisposing factors for atopic dermatitis.

Filaggrin is essential for skin barrier function because it helps to form a protective layer at the surface to keep water in and foreign organisms out.

People with filaggrin mutations suffer a reduction in, or absence of, filaggrin, enabling foreign substances to enter the skin and be detected by the immune system, causing the development of inflamed skin, characteristic of eczema.

In some people, this leakage of substances through the skin primes the immune response leading to asthma when foreign substances enter the lungs.

The researchers found that about 10 per cent of Europeans carry some kind of mutation that switches off the filaggrin gene, causing the skin condition ichthyosis vulgaris.

They showed in four independent experiments that these common mutations were a major predisposing factor in eczema and asthma.

In addition, they studied the medical histories of a number of Danish babies, finding a strong association between filaggrin mutations and eczema.

The results also showed that more than 60 per cent of the children carrying filaggrin mutations developed eczema within the first two years of life.

WHAT DID RESEARCHERS SAY?

Lead researcher Professor Irwin McLean, professor of human genetics at the University of Dundee, told GP that in future, this discovery could lead to the development of drug-based therapies to target the mutated gene or work with specific protein systems to combat and even prevent eczema.

'Anti-inflammatory drugs and emollients treat the symptoms of eczema, not the cause,' he said. 'Eventually, we may be able to use a drug-based therapy that targets these genes and encourages the skin to produce more of certain substances. If you augment the barrier function in early life, the person may not go on to develop eczema.'

Professor McLean acknowledged that such treatment could be five to 10 years away. But he added that, if good preventive treatment did become available, babies could be screened for the mutation at birth and all those with genetic variants predisposing to eczema offered treatment.

He also plans to study patients who carry the gene fault, but have not gone on to develop eczema. He believes this group may provide clues about environmental triggers for eczema and how it can be prevented.

WHAT DO OTHERS SAY?

The major UK skin charities have welcomed the breakthrough, but warn that patients should continue current treatments.

A spokeswoman for the British Skin Foundation, which helped to fund the research, described the developments as 'an encouraging first step, which could lead to new, improved treatment'.

Margaret Cox, chief executive of the National Eczema Society, which also funded the research, told GP that it offered serious hope to eczema patients.

'It is an important piece of the jigsaw in terms of understanding the development of eczema,' she said. 'It confirms what we suspected - skin barriers play a large part.

So it is important for patients to continue their emollient regime and to use existing treatments, such as topical steroids, for flare-ups.'

- GPletters@haynet.com
- Nature Genetics 2006;38:337-42
- Live links at GPonline.com

WHAT THE PAPERS SAID
"Asthma and eczema linked to mutant gene" - THE GUARDIAN
"Gene hope for eczema THE TIMESsufferers" - "Eczema and asthma
breakthrough" - DAILY MAIL

INFORMING PATIENTS

- Researchers have found the gene that causes dry, scaly skin and makes people susceptible to eczema.

- In future, drugs may be able to target this gene, but this is five to 10 years away.

- If therapies are developed, babies could be screened for the mutation at birth.

- Patients should continue to use existing treatments, such as topical steroids.

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