Clear link for genetic component of obesity

Scientists in the UK have identified the clearest genetic link yet to obesity in the general population, suggesting that people with two copies of a specific gene have a 70% higher risk of being obese.

Mouse models have shown genetic links to obesity - now a link has been shown in humans

The researchers from the University of Oxford and the Peninsula Medical School, Exeter, found a strong association between an increase in body mass index (BMI) and a variation - or allele - of the gene FTO.
“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 lead researcher Professor Mark McCarthy from 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.”
The study found that people carrying one copy of the FTO allele have a 30% increased risk of being obese compared to a person with no copies. However, a person carrying two copies of the allele has a 70% increased risk of being obese, being on average 3kg heavier than a similar person with no copies. Amongst white Europeans, approximately one in six people carry both copies of the allele.

The team first identified the genetic link to obesity through a genome-wide study of 2,000 people with type 2 diabetes and 3,000 controls. The researchers then tested a further 37,000 samples for the FTO gene from Bristol, Dundee and Exeter as well as a number of other regions in the UK and Finland.

“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,” explains Professor Andrew Hattersley from 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.”

The study was part of the Wellcome Trust Case Control Consortium, one of the biggest projects ever undertaken to identify the genetic variations that may predispose people to or protect them from major diseases.