SCIENTISTS have hailed as a major breakthrough the discovery of a defective gene that causes eczema and asthma.
An international team of researchers led by experts from Dundee University found that the gene is responsible for producing a protein that makes skin waterproof and keeps out infections.
In an Irish study, about two-thirds of children with eczema were found to have a defect in the gene and a study of Danish children found that more than 60 per cent with the mutated gene acquired the disease in the first few years of life.
A third study of children in Scotland found a "very strong association" between the gene and eczema and asthma.
The news, revealed in two academic papers today and next month in the journal Nature Genetics, was hailed as a "real step forward", by the National Eczema Society, which added: "Above all, it answers the age-old question asked by most eczema sufferers - 'why?'"
Another group said it held out the prospect of a treatment - or even a cure - with "truly life-changing possibilities" for people with the diseases. More than five million people in Britain suffer from asthma, and six million from eczema.
Until now, doctors could only treat the symptoms of eczema and the related dry skin condition ichthyosis vulgaris using ointments or anti-inflammatory drugs.
Now the gene defect that underlies most cases is known, scientists have a target and the Dundee team is already looking for drugs that will stimulate production of the protein, called filaggrin.
About five million people in the UK alone make only 50 per cent of the normal amount of filaggrin protein and have dry and flaky skin.
But one in 500 people, or about 120,000 in the UK, have both their copies of the filaggrin gene knocked out by mutations and have no filaggrin protein in the skin. They suffer a severe and persistent form of eczema, where the skin becomes infected and inflamed, causing terrible itching and flaking. Professor Irwin McLean, one of the lead scientists on the work at Dundee, along with Dr Frances Smith, told The Scotsman he was already in contact with a drug screening programme being set up at the university in the hope of finding a radical new treatment.
"Finding this major gene for atopic dermatitis [eczema] and asthma allows us for the first time to understand what goes wrong in the skin of these patients and paves the way for development of treatments or preventive measures," he said.
If too little or no filaggrin is produced, the skin is not an effective barrier, allowing moisture to escape from the body and foreign substances to get in.
Eczema is caused when foreign bodies enter the skin and are attacked by the immune system, causing inflammation of the skin.
It is thought the immune system can become primed to attack normally harmless material - usually kept out by the skin barrier - and that this causes asthma when foreign substances enter the lungs.
Prof McLean said analysing the filaggrin gene was "one of the toughest things we have ever done", a task that several top genetic laboratories around the world had given up on.
Matthew Patey, director of the British Skin Foundation, said: "It is extremely encouraging to see the ongoing results of this research, which indicate positive steps towards eliminating the suffering of eczema and related skin disorders."
'It really affects my everyday life. When it's bad I end up in hospital'
UP UNTIL she was ten, Jade Williamson spent her life wrapped head-to-toe in bandages with daily trips to hospital.
She was diagnosed with eczema when she was only six-months-old, and then at the age of six developed asthma. However, the 22-year-old from Rosyth has refused to let either condition get the better of her, and is studying at Lauder College to become a personal exercise trainer.
"It really affects everyday life - your life revolves around having it. If your eczema is bad and your asthma is bad, then you get depressed," she said.
"When it is bad I usually end up in hospital. My skin gets really infected and if you scratch it, it falls off. I've been hospitalised quite a few times. Nine weeks was the longest time."
The discovery of a gene that causes both asthma and eczema raises the prospect of a breakthrough new treatment, and she can hardly wait for the day when her life no longer revolves around either condition.