QUEENSLAND researchers have discovered the genetic link between the three most common allergic conditions - asthma, hay fever and eczema.
In a study with a sample size roughly equal to the population of Canberra, the Brisbane-based QIMR Berghofer Medical Research Institute scientists have discovered 136 genes which put people at risk of developing these conditions.
QIMR Berghofer head of asthma genetic research Manuel Ferreira said it was the first time the genetic risk factors for all three conditions had been examined together.
Dr Ferreira said researchers believed the genes increased the risk of asthma, hay fever and eczema by affecting how immune system cells worked.
He said it was hoped the study of 360,838 people would help identify a drug which could be targeted at some of these genes to treat allergies.
"We don't know yet but each gene could point us to a new drug that might, in fact, be used to treat all three conditions," he said.
Using a smaller sample of 1200 people, researchers examined whether environmental factors affected the "expression" of these genes.
Dr Ferreira said participants were quizzed about smoking status, their body mass index (BMI), birthweight, number of siblings and whether their mothers smoked during pregnancy to determine if any of these factors caused the genes to be switched on or off.
Smoking was the only environmental factor for which results were conclusive - with researchers finding that a gene called PITPNM2 was more likely to be switched on in smokers.
Edison Flynn, 4, has suffered with all three conditions since he was just a baby.
His mother Madeleine said he now used an inhaler to manage his asthma and thick moisturising cream for his eczema, which had improved vastly in the past few years.
"(A new drug) would be such a relief to parents like me," she said.
"Especially with little babies, under the age of three, it is just so stressful."
Ms Flynn said both she and her husband also had allergies.