European and Canadian researchers have, for the first time, drawn a map of genetic risk factors that can lead to two forms of severe obesity: early-onset obesity in children, and morbid obesity in adults.
A genetic study of 1,380 Europeans with early-onset and morbid adult obesity was led by French researchers Dr. David Meyre, of the Institut national de la santé et de la recherche médicale (Inserm), and Dr. Philippe Froguel, director of the Centre National de la Recherche Scientifique (CNRS). Dr. Rob Sladek, Dr. Constantin Polychronakos and Dr. Alexandre Montpetit, of McGill University and the McGill University and Génome Québec Innovation Centre, made key contributions to the discovery, along with researchers from France, Britain, Finland, Switzerland and Germany.
The results were published Jan. 19 in the journal Nature Genetics. Finding the genetic cause of a medical problem can often lead researchers along the right path toward an eventual treatment or cure or to help identify people who might be at risk.
"The idea was not just to look at run-of-the-mill obesity, but look for genetic factors that may affect people who have more severe problems with their weight," said Dr. Sladek, an assistant professor in the Department of Human Genetics and Endocrinology. "This includes children who become obese at a young age, before the age of six. We also studied the genomes of adults who had a familial history of severe obesity, with a body-mass index greater than 40." People are generally defined as "overweight" if they have a body-mass index greater than 25.
"The family approach being undertaken by our collaboration with our colleagues in France is going to become important for future large-scale genetic studies," Sladek continued. "Our suspicion is that a lot of the genetic changes that make people obese will turn out to be variants that run in families or in segments of the population, rather than things that are very common across the population. In terms of diabetes, we think that perhaps 90 per cent of the genetic risk could come from these familial or even personal genetic variants."
"We are proud of this announcement, which once again confirms the scientific excellence and talent of Québec's scientists," said Paul L'Archevêque, President and CEO of Génome Québec. "These findings, which are the direct result of studies co-financed by Génome Québec, clearly show the strategic role of genomics in the search for solutions to improve human health. We would also like to underline the cooperation among the institutes, an initiative that made this major advance possible. Congratulations to the McGill University and Génome Québec Innovation Centre team, and especially to Alexandre Montpetit who trained a group from CNRS on genotyping data analysis on the Illumina platform."
- Meyre et al. Genome-wide association study for early-onset and morbid adult obesity identifies three new risk loci in European populations. Nature Genetics, 2009; DOI: 10.1038/ng.301
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