Genetic Breakthrough Explains Dangerously High Blood Glucose Levels

Canadian, French, and British researchers have identified a DNA sequence that controls the variability of blood glucose levels in people. This is a potentially significant discovery because high blood glucose levels in otherwise healthy people often are indications of heart disease and higher mortality rates. The results will be in the online version of the journal Science.

The research was conducted by Dr. Phillippe Froguel and colleagues at Imperial College London and le Centre national de la recherche scientifique (CNRS) in Lille, France, in collaboration with Dr. Robert Sladek, Dr. Constantin Polychronakos and their teams at McGill University and the McGill University Health Centre (MUHC) in Montreal. Dr. Ghislain Rocheleau, a post-doctoral fellow in Dr. Sladek’s lab, is the study’s co-first author. The scientists worked with data collected from a large genome study originally conducted for diabetes research that looked at over 390,000 different locations—or loci—on the human genome.

In this study, researchers looked at the genetic code of healthy, non-diabetic individuals whose blood glucose levels were in the normal range. They discovered that a single DNA mutation within three different genes explained, in part, why some individuals have high or low blood glucose levels. The researchers believe that these genes actually affect the threshold level of glucose in the bloodstream, which triggers the secretion of insulin. The higher the threshold, the higher the blood glucose level will rise before insulin starts to regulate it.

“These sequences explain about five percent of the normal variation in blood glucose levels between otherwise healthy people,” explained Dr. Sladek, of McGill’s Faculty of Medicine, the Department of Human Genetics, the MUHC Research Institute and the McGill University and Génome Québec Innovation Centre. “Five percent may not sound huge, but for complex traits, that’s rather a lot. By contrast, hundreds of different genes influence height.”

Release date: May 1, 2008
Source: McGill University