12 November 2007
ByAppeared in BioNews 433
Scientists have moved a step closer to understanding how a gene previously linked to obesity makes people prone to weight gain, according to a study published last week in the journal Science. The discovery may help scientists to develop new treatments to combat the increasing numbers of people who are being diagnosed with obesity each year.
In April, British scientists discovered a link between obesity and a gene known as FTO. They reported that people who carry two copies of a particular version of the FTO gene -an estimated 16 per cent of the population - are, on average, three kilograms heavier than people who do not have the variant, while those who carry just one copy of the gene variant - an estimated 50 per cent of the UK population - are around 1.6kg heavier.
At the time, scientists didn't know why the gene tended to make people overweight, but, thanks to the combined work of scientists from Oxford, Cambridge and Cancer Research UK in London, scientists now have some idea of how the gene works. The researchers found clues that the FTO gene may be involved in switching genes on or off. Furthermore, they also discovered that the gene is active in an area of the brain - the hypothalamus - which is responsible for regulating appetite and fullness.
Professor Stephen O'Rahilly, who led the Cambridge arm of the study, said that the findings of the study provided an important 'first glimpse', but that 'a lot of work is still needed to work out how [the gene's] actions influence body weight.' Nevertheless, he is optimistic that future treatments will be possible: 'As the activity of FTO can be altered by small molecules like metabolites, it is possible, in the future, that FTO could be manipulated therapeutically to help treat obesity,' he said.
Although the discovery provides scientists with a new avenue to explore in the hunt for treatments to combat obesity, further research will be needed to gain a full understanding of the genetic basis of obesity, Professor Frances Ashcroft, a physiologist at Oxford University, told the Guardian. "What we have here [with FTO] is something that is causing obesity in the general population, not a rare mutation in a single gene that causes a dramatic effect on body weight. [Obesity] is a common disease and that means it probably will occur in combination with other genes to make the obesity phenotypes,' she said.