Scientists at Dundee University have helped uncover a genetic defect that can triple the risk of a child developing a life-threatening peanut allergy.
Peanut allergy affects 1-2% of all children, but rates of the condition have increased dramatically over the past 30 years although no one knows why.
Now research led by scientists in Dundee has identified the key role the gene Filaggrin can have in causing the condition. Filaggrin has previously been shown by the team to be a significant factor in causing eczema and asthma, conditions often linked to peanut allergy.
“It was a logical next step to investigate whether Filaggrin may also be a cause of peanut allergy, since a child may develop all three of these diseases together,” said Dr Sara Brown, Wellcome Trust intermediate clinical fellow in the division of molecular medicine at Dundee.
“Allergic conditions often run in families, which tells us that inherited genetic factors are important. In addition to that, changes in the environment and our exposure to peanuts are thought to have been responsible for the recent increase in peanut allergy seen in the western world in particular.
“Now for the first time we have a genetic change that can be firmly linked to peanut allergy.”
Filaggrin gene codes are for a protein that helps to make the skin a barrier against irritants and allergies. Any changes to the gene reduce the skin’s effectiveness as a barrier and result in more substances entering the body, which can then trigger allergic reactions.
The study has found that one in five peanut allergy sufferers have a Filaggrin defect and that those with a defect are three times as likely to suffer a peanut allergy than those with a normal gene.
“We knew that people with a Filaggrin defect were likely to suffer from eczema, and that many of those people also had peanut allergy,” said Professor Irwin McLean, who is also based at Dundee. “What we have now shown is that the Filaggrin defect is there for people who have peanut allergy but who don’t have eczema, which shows a clear link between Filaggrin and peanut allergy.
“The Filaggrin defect is not the cause of peanut allergy but we have established it as a factor in many cases. We don’t yet know enough about the causes of peanut allergy but this is an important step forward.”
The findings are published today in theJournal of Allergy and Clinical Immunology.
Professor McLean said the Filaggrin findings suggest peanut allergy may be caused by substances entering the body through the skin though it could also have an effect in the gastro-intestinal area.
He also stressed that, as Filaggrin defects were found in one in five peanut allergy cases, more research must be carried out into the genetic risk factors for the condition.
Photo by Flickr user EuroMagic.