Scientists have zeroed in on 15 more mutations of the gene responsible for the debilitating disorders eczema and asthma, in children.
The study claims to make treatment more specific for ethnic groups as well as pinpoint various forms of the gene's effects by genetic tests.
Says Irwin McLean at the College of Medicine, Dentistry and Nursing at the University of Dundee, who led the study:" Once we cracked this exceptionally difficult gene, we were surprised to learn how many different defects in filaggrin were waiting to be discovered, not only in European people, but other populations worldwide."
Last year the team had discovered that the mutated gene, which is carried by five million people in Britain, produced a protein called filaggrin, which brings about inflamed skin.
At present the latest research has shown five of these mutations are prevalent in European patients with 9 percent of the population believed to carry the defect. It was seen that two of these mutations were prevalent in those tested from Oriental backgrounds.
Eczema is known to affect around one in five UK children. Knowing which mutations to look for could allow doctors to identify individuals at risk of the disease early on. It might also allow scientists to develop treatments.
Until filaggrin's role was identified, researchers had mostly assumed that problems with the immune system were responsible for the condition. At present, research is focusing on drugs that can boost production of the filaggrin protein in skin.
Filaggrin, which is normally found in the outer layers of the skin, provides a preventative barrier. In the mutated genes filaggrin is missing which causes inflammation.
The researchers searched through filaggrin sequences in 23 sufferers from Ireland, Scotland, the Netherlands and Austria in order to find out the genetic errors that cause these disorders.
This search threw up 12 changes to the normal sequence that prevented or reduced protein production from the gene. A further study of five Irish children with severe eczema identified three more mutations.
When the team looked at 188 Irish children with eczema they found that around half carried at least one mutation in the filaggrin gene that would prevent production of the protein.
The study is published in the journal Nature Genetics.
Mutations to the filaggrin genes, which come in pairs, are thought to damage the outer layers of the skin, allowing the entry of allergens, which drive the immune system haywire.
A mutation to one gene is enough to cause ichthyosis vulgaris, a dry, scaly skin. If both genes are faulty, the problems lead to eczema, asthma, and, it is suspected, hayfever and peanut allergy.
The researchers hope that the study findings will lead to more effective treatments and preventative measures in babies.
Allergic conditions such as eczema, hayfever and food intolerances have increased dramatically. Almost half of the UK population is thought to have some form of allergy.