Non-coding genomic regions may play an important role in risk of type 2 diabetes.
Understanding of the role of the non-coding genome in the regulation and control of gene expression has been growing rapidly in recent years. Now, a major new study published in Nature Genetics links variation in genomic sequences involved in the regulation of pancreatic islet cell gene activity with risk of type 2 diabetes.
Type 2 diabetes (T2D) affects over 300 million people and arises from dysfunction of the pancreas, specifically of insulin production and the associated control of blood sugar levels. It is a growing public health problem around the world, largely due to the rapidly increasing incidence of obesity.
However, risk of the condition is also influenced by other environmental and lifestyle factors, and by genetic factors. Genetic studies have formed a central part of efforts to understand how diabetes arises (and hopefully ultimately improve risk prediction, prevention and treatment of the condition), but many of the genomic regions associated with the disease proved to have unknown functions.
In this study, researchers mapped the regulatory networks of human insulin-producing pancreatic islet cells, They identified specific enhancer domains that were key determinants of islet-cell specific gene activity. Sequence variants associated with type 2 diabetes and fasting blood sugar levels were enriched in these same regions and were shown to disrupt transcription factor binding and gene expression.
They conclude that individual sequence variation in pancreatic islet cell regulatory regions underlies T2D susceptibility. Lead researcher Professor Jorge Ferrer of Imperial College London said: “Many people have small DNA variants in such regulatory elements, and these variants affect gene expression in the cells that produce insulin. This knowledge will allow us to understand the detailed mechanisms whereby specific DNA variants predispose to diabetes”.