Researchers identify gene linked to obesity
Scientists have identified a gene which is linked to obesity. People with two copies of a particular version of the FTO gene are 70% more likely to be obese that people with no copies. The research, which was funded by a number of agencies including the Sixth Framework Programme (FP6), is published online by the journal Science. Previous studies on twins and adopted children have shown that there is a genetic component to obesity, but until now researchers have been unable to pinpoint precisely which genes are involved. This latest discovery came about during research by the Peninsula Medical School, Exeter and the University of Oxford into the genetic causes of diabetes. Most genes linked to diabetes are involved in insulin production. However, the researchers realised that people with a particular variant (or allele) of the FTO gene were at a higher risk of diabetes because they had a higher body mass index (BMI). The initial study involved 2,000 diabetics and 3,000 non-diabetics. Further tests on samples from 37,000 people from across the UK and Finland confirmed the association between the FTO gene and BMI. People with one copy of the allele were found to have a 30% increased risk of obesity compared to someone with no copies, while people with two copies of the allele have a 70% increased risk of obesity. On average, people with two copies of the gene are three kilos heavier than people with no copies, and the effect of the gene could be detected in children as young as seven. According to the researchers, one in six white Europeans carry both copies of the affected allele. 'As a nation, we are eating more but doing less exercise, and so the average weight is increasing, but within the population some people seem to put on more weight than others,' commented Professor Andrew Hattersley of the Peninsula Medical School. 'Our findings suggest a possible answer to someone who might ask 'I eat the same and do as much exercise as my friend next door, so why am I fatter?' There is clearly a component to obesity that is genetic.' Additional studies revealed that the gene increases BMI by increasing the amount of fatty tissue, and not by changing height, bone mass or lean mass, all of which can also affect the BMI. The next challenge for researchers is to understand how the different versions of the FTO gene work to affect BMI. 'Even though we have yet to fully understand the role played by the FTO gene in obesity, our findings are a source of great excitement,' said Professor Mark McCarthy of the University of Oxford. 'By identifying this genetic link, it should be possible to improve our understanding of why some people are more obese, with all the associated implications such as increased risk of diabetes and heart disease. New scientific insights will hopefully pave the way for us to explore novel ways of treating this condition.'
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