Clues about how the environment could be contributing to the development of type 1 diabetes are uncovered in Nature Communications this week. The study investigates the contribution of the epigenome - markers on the genome that alter how genes are expressed, and that can be modified by environmental factors - to disease development. Epigenetic changes to immune genes are identified in patients with type 1 diabetes, although their precise involvement requires further examination.

The incidence of type 1 diabetes has dramatically increased in the past decade, suggesting that environmental factors (such as infections or diet) might have a major role in disease development. When studying the development of a complex disease, distinguishing the role of genetics from the role of the environment has been challenging for scientists and clinicians. Our environment can modify how epigenetic marks are added on to the genome, changing cell function; thus, studying the epigenome is a powerful tool to measure the influence of the environment on the how our cells work.

To identify the role of the environment in the development of type 1 diabetes, Dirk Paul, David Leslie and colleagues studied a large group of identical twins where one sibling was healthy and the other had the disease. They studied both the twins’ genome and epigenome and compared them, finding changes in the epigenome of the diabetic patients. Many of these differences could not be explained by genetic factors. Some epigenetic changes were associated with the regulation of immune cell function. This finding is promising and may provide new clues about disease development, as type 1 diabetes is an autoimmune disease.

However, further research will be needed to clarify the mechanism through which these epigenetic changes contribute to the development of the disease and the environmental factors that may be influencing them.