Half carry obesity genetic variation

Half of the UK population may be at increased risk of obesity, type 2 diabetes and heart disease, due to a genetic variation which makes carrier prone to weight gain, according to a study published in the journal Nature Genetics last week. The researchers, based at Imperial College London and other international institutions, believe that the discovery may speed the development of genetic screening programmes for identifying those at greatest risk from obesity-related health problems.

'A better understanding of the genes behind problems such as diabetes and cardiovascular disease means that we will be in a good position to identify people whose genetic inheritance makes them most susceptible,' said study leader Professor Jaspal Kooner. 'We can't change their genetic inheritance. But we can focus on preventative measures, including life-style factors such as diet and exercise, and identifying new drug targets to help reduce the burden of disease', he said.

Carriers of the genetic variant, which was a third more common among the Indian Asian population, tended to be 2kg heavier and be 2cm larger around the waist. The researchers believe that this may help to explain the increased incidence of obesity and diabetes among Asian Indians - who make up 25 per cent of the world's population, but are expected to account for 40 per cent of the world's heart disease by 2020.

In the hunt for genes involved in obesity, the researchers examined the genetic code of 30,000 British citizens of European and Asian descent. They pinpointed a gene sequence located near to a gene called MC4R, which is believed to play a role in regulating energy levels by influencing appetite and metabolism. The research was carried out as part of the London Life Sciences Population study (LOLIPOP) - an ongoing project aimed at examining the genetic basis of obesity, diabetes and heart disease among UK citizens.

Looking at 90,000 people from Sweden, an independent study by researchers from Oxford University and the Wellcome Trust's Sanger Institute in Cambridge, linked another region near to the MC4R gene with obesity risk. The study, led by Ines Barroso from the Sanger Institute, found that carriers were on average 1.5kg heavier, with children gaining weight almost twice as fast as adults.

Last year, British scientists reported that people who carry two copies of a particular version of a gene called FTO - an estimated 16 per cent of the population - are, on average, 3kg 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.

'The precise role in obesity of genetic variants in FTO and near MC4R remains to be discovered, but we can now begin to understand the biological consequences of these', Barroso told the Guardian.