Uncovering a missing piece in the asthma puzzle

Epigenetics could reveal the links between environmental and genetic factors in asthma, and provide clues to preventative treatments

August 19, 2015

Canada ranks sixth in the world in the prevalence of asthma among young teens. Why do some children get asthma while others do not? It's a critical question to which there's no clear answer.

During the past two decades, research conducted by Dr. Denise Daley, Associate Professor in the Department of Medicine, Centre for Heart Lung Innovation, at the University of British Columbia and St. Paul's Hospital,  has helped provide the evidence for how people's genes affect their risk of asthma.

"Asthma is a very complex disease," says Dr. Daley. "There's a combination of genetics, environment, and gene-environment interactions."

Epigenetic research, which examines how environmental factors create long-term changes in gene activity, is emerging as a critical field for understanding how early experiences, in the womb or childhood, can affect health.

"About 80% of the risk for asthma is due to shared genetic risk factors," says Dr. Daley.

However, there is no single "asthma gene." There are dozens of genes involved in the condition, and the behaviour of these genes depends in part on environmental factors, such as exposure to tobacco smoke in the womb.

"This is where studying the epigenome is potentially very important because it is going to inform us about how the genome has responded to environmental exposures in ways that might predispose a child to asthma."

Dr. Daley's goal is to identify ways to prevent a child's first wheeze.

"By the time a child is diagnosed with asthma, airway remodeling has already occurred - the damage is done," says Dr. Daley.

Her current research project, supported in part by the Canadian Institutes of Health Research (CIHR), is exploring the links between known asthma-related genetic variations, exposure to tobacco smoke during pregnancy or as a young child, and resulting epigenetic changes.

"For the first time we'll be able to actually assess epigenetic changes and say, 'Is this actually the mechanism related to asthma?'."

Dr. Daley sees the research contributing to cost-effective, population-level preventative programs, such as using probiotics to boost a child's gut microbiome – the bacteria living in the digestive tract. Disturbances in these bacteria are known to be linked with asthma, and there are bacteria that influence the human epigenome through B-vitamin production.

Epigenetics, environment and health

In the past five years, due to technological advances, epigenetics has emerged as a major area of health research and promise. While our DNA sequence is fixed, epigenetic characteristics are changeable. Epigenetics involves molecules, or marks, that regulate how the DNA is organized, and which genes are turned "on". Thus, epigenetic research could lead to new therapies, and successful epigenetic drugs are already used in cancer treatments.

CIHR is building epigenetics research capacity through STAGE, Canada's only formal training program in genetic and epigenetic epidemiology, and the Canadian Epigenetics, Environment and Health Research Consortium, which supports leading edge research on the role of epigenetic and environmental interactions in human health and disease.

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