Scientists have made a huge breakthrough in understanding the genetics behind asthma, hay fever and eczema – the three most common allergic conditions in the world – providing fresh hope for future treatment options.

In a study published in the scientific journal Nature Genetics, an international team of researchers led by Dr Manuel Ferreira from the QIMR Berghofer Medical Research Institute pinpointed over 100 genetic risk factors that give rise to the three conditions, which often co-exist in the same people.

“We already knew that [asthma, hay fever and eczema] were similar at many levels,” Dr Ferreira said.

“For example, we knew that the three diseases shared many genetic risk factors. What we didn’t know was exactly where in the genome those shared genetic risk factors were located.”

The researchers studied the genomes of over 360,000 people and identified 136 genetic risk factors – 73 of which had not previously been reported – that influence the activity of 132 other nearby genes, which in turn affect the functioning of our immune system

“We think that these genes influence the risk of asthma, hay fever and eczema by affecting how the cells of the immune system work,” Dr Ferreira said.

Banish the sneeze. Photo: Getty

These findings are significant because not only do they shine a light on the specific genes that cause these allergic conditions, but also provide clues to their origins.

According to the Australian Institute of Health and Welfare, one in nine Australians (around 2.5 million people) reported having asthma in 2014-15; and nearly one in five Australians (4.5 million people) suffered from hay fever in the same year.

Dr Ferreira and his team found that a vast majority of the genetic risk factors were shared by asthma, hay fever and eczema, which indicates that similar biological processes can give rise to all three.

“This knowledge helps us understand why allergies develop in the first place and, potentially, gives us new clues on how they could be prevented or treated.”

Only six genetic factors out of the 136 that were identified were disease-specific.

Professor Mimi Tang, an expert in allergic and immune deficiency disorders from the Murdoch Children’s Research Institute, said the findings were “exciting” and would help direct further research into the mechanisms of the three conditions.

“This is an exciting study as it shows for the first time gene variants associated with increased risk of disease that are common across the different allergic conditions,” she told The New Daily.

“We have known for many decades that there is a strong association between the different allergic conditions and this [study] would explain to some extent this association.”

According to Professor Tang, the epigenetic associations – that is, environmental factors that can ‘switch’ genes on and off – highlighted “the importance of environmental exposures in determining disease expression”.

For example, the researchers found that a gene known as PITPNM2 was more likely to be ‘switched off’ in people who were smokers, which increased the risk of developing allergies.

“We know that gene-environment interactions mediated through epigenetic regulation is key in development of modern non-communicable diseases including allergic diseases,” Professor Tang said.

As part of the study, Dr Ferreira and his team also identified drugs that could be used to target some of the genes in question, which could influence avenues for future treatment strategies.

“The first step would be to test those drugs in the laboratory.”