Experts, lead by the University of Dundee, have discovered the gene which causes genetic skin conditions affecting millions of people.
Experts on genetic skin disorders at the University of Dundee, with collaborators in Dublin, Glasgow, Seattle and Copenhagen, have discovered the gene that causes dry, scaly skin and predisposes individuals to atopic dermatitis (eczema). Some of these individuals also develop a form of asthma that occurs in association with eczema. This work has been published in two consecutive papers in the March and April editions of the top genetics journal, Nature Genetics.
Currently, only symptomatic treatment of ichthyosis vulgaris and eczema is possible, using emollients and ointments to try to prevent the skin drying out or anti-inflammatory drugs to treat the inflamed skin in eczema. Now that the underlying gene defect behind this disorder is known, it will be possible to design new more effective therapies to tackle the root cause of the problem, rather than treating the symptoms. The Dundee group is already working on developing methods to treat and even prevent these diseases.
The gene in question produces a protein called filaggrin which is normally found in large quantities in the outermost layers of the skin. This protein is essential for skin barrier function, helping to form a protective layer at the surface of the skin that keeps water in and keeps foreign organisms out.
Reduction or complete absence of this important protein leads to impaired formation of the skin barrier. As a result, the skin dries out too easily and in addition, the outer layers of the skin are poorly formed and constantly flake off. As well as keeping water in, the skin barrier normally keeps foreign substances out of the skin. 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 appears to lead to asthma when foreign substances later enter the lungs.
The first study, led by geneticists Professor Irwin McLean and Dr Frances Smith in Dundee and their dermatology colleague, Dr Alan Irvine, Our Lady's Hospital for Sick Children, Dublin, discovered that about 10% of European people carry a type of genetic mutation that switches off the filaggrin gene and this causes a very common dry, scaly skin condition, known as ichthyosis vulgaris. About 5 million people in the UK alone make only 50% of the normal amount of filaggrin protein and have a milder form of the disorder where the skin is dry and flaky. About 1 in 500 people, or 120,000 people in the UK, have both copies of the gene knocked out by genetic mutations and have no filaggrin protein whatsoever in the skin. These individuals have a severe and persistent form of the disease, often requiring specialist treatment.