An international team, made up of scientists from several different universities, has successfully identified over 100 genetic risk factors that increase a person's chances of developing three common allergic conditions: asthma, hay fever and eczema. The giant study analyzed the genomes of over 360,000 people and found 136 genetic risk variants that coincided with one of the three diseases, including 73 previously unknown risk variants.

"Asthma, hay fever and eczema are allergic diseases that affect different parts of the body: the lungs, the nose and the skin," says Manuel Ferreira, lead author on the study. "We already knew that they were similar at many levels. 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."

As well as greatly enhancing our overall knowledge of key genome triggers for disease, the data is being used to look at several drugs already in development for other conditions that could now be pivoted into potential treatments for allergic diseases.

"We think that these genes influence the risk of asthma, hay fever and eczema by affecting how the cells of the immune system work," says Ferreira. "Importantly, we have identified several drugs that we believe could be targeted at some of these genes to treat allergies. The first step would be to test those drugs in the laboratory."

The study identified 29 genes that are already being researched as drug targets. Twenty of those drugs currently in development are for other diseases, including cancer and cardiovascular disease.

This research indicates that some of these drugs in development may have secondary effects that attenuate allergy symptoms. Six genes in particular have been highlighted by the study with an existing drug match that the researchers suggest should be prioritized for preclinical testing for allergic disease.

A variety of environmental factors that affect gene expression were also examined in the study. Smoking was one of the most prominent factors in influencing the genetic risk of allergic disease.

"For example, we found one gene – called PITPNM2 – that is more likely to be switched off in people who smoke," adds Ferreira. "If this gene is switched off, then the risk of developing allergies increases."

The major study offers hope to sufferers that treatments could be found to tackle all three major allergic conditions.

The research was published in Nature Genetics.