Researchers have identified that an eczema gene increases people’s risk of being sensitive to common allergic foods, but they say other unknown environmental factors determine whether people develop a full blown food allergy or food tolerance.
Researchers from Murdoch Childrens Research Institute studied 700 infants and collected DNA samples to investigate the association between the changes in the eczema gene filaggrin (FLG), and the risk of developing food allergy in one year old infants.
The study found the infants who had a FLG gene change had an increased risk of having a positive skin prick test to common allergic foods in the first year of life. However, they found the gene change didn’t help predict which of those children with a positive skin prick test developed food allergy or were tolerant to the food.
The Filaggrin protein functions to protect the skin from water loss. The study found that the risk of developing a positive skin prick test to food was over and above the risk of developing eczema.
Researchers say the findings support the hypothesis that sensitisation to food can occur through the skin and poor skin care may increase the risk for people to become sensitised to common allergenic foods.
However the gene change did not increase the risk of food allergy beyond just being sensitised to food suggesting that another as yet unidentified factor is important in converting high risk sensitised infants to a food allergic status.
Co-lead researcher, Tina Tan, a University of Melbourne student based at the Murdoch Childrens Research Institute, said this is the first study to identify the specific gene that predisposes people to a sensitisation to food.
“Our results confirm that genetics play a role in the development of food sensitisation, and that the decreased skin barrier function caused by the gene change increases the risk of food sensitisation in early life.”
Study leader, Professor Katie Allen said while the results show genetics play a role, its evident other factors are at play in determining who goes on to become allergic to food.
“While we found genetics play a role, we found other as yet undetermined factors are important in to direct the immune response towards either becoming food tolerant or allergic in early life.”
“So it appears that the development of food allergy is caused by a combination of inherited genetic factors and poorly understood environmental ones. Our focus now is to identify these other environmental factors that with the mutated gene, lead to food allergy.”