Scientists discover genetic link to obesity

A fifth of people in England are classified as obese

13 April 2007

Major genetic study identifies clearest link yet to obesity risk

Scientists have identified the most clear genetic link yet to obesity in the general population as part of a major study of diseases funded by the Wellcome Trust, the UK's largest medical research charity. People with two copies of a particular gene variant have a 70 per cent higher risk of being obese than those with no copies.

The team of scientists, including Professor Graham Hitman from Queen Mary’s Institute of Cell and Molecular Science, identified a genetic link to obesity through a genome-wide study of 2,000 people with type 2 diabetes and 3,000 controls. This 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. Through this genome-wide study, the researchers identified a strong association between an increase in body mass index (BMI) and a variation, or "allele", of the gene FTO. Their findings are published online today in the journal Science.

Professor Hitman explained: “We currently live in a blame culture which when people gain weight it is entirely their fault. This exciting research, led by Exeter and Oxford, is the culmination of 15 years work and points to variation in a gene that if you have one copy present, in almost 50 per cent of the general population, it will lead to a gain in weight of 1.2kilos or put 1cm on your waist; if you have 2 copies present, in 16 per cent of the population, then you will gain almost 3kilos, than if you do not have this variation. This therefore confirms that whilst improving lifestyle is still the key to reducing the obesity epidemic, some people will find it harder to change their weight than others because of their genes. In future when we know more about the function of this gene (FTO) we may also be able to help people to lose weight more effectively despite their genes.”

Obesity is a major cause of disease, associated with an increased risk of type 2 diabetes, heart disease and cancer. As a result of reduced physical activity and increased food consumption, the prevalence of obesity is increasing worldwide. According to the 2001 Health Survey for England, over a fifth of males and a similar proportion of females aged 16 and over in England were classified as obese. Half of men and a third of women were classified as overweight.

The study found that people carrying one copy of the FTO allele have a 30 per cent increased risk of being obese compared to a person with no copies. However, a person carrying two copies of the allele has a 70 per cent 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 researchers currently do not know why people with copies of the FTO allele have an increased BMI and rates of obesity.

The findings were welcomed by Dr Mark Walport, Director of the Wellcome Trust. "This is an exciting piece of work that illustrates why it was so important to sequence the human genome," says Dr Walport. "Obesity is one of the most challenging problems for public health in the UK. The discovery of a gene that influences the development of obesity in the general population provides a new tool for understanding how some people appear to gain weight more easily than others. This discovery, along with further results expected from the Wellcome Trust Case Control Consortium later this year, will open up a wealth of new avenues to understand and treat common diseases."

Ends

"A common variant in the FTO gene region is associated with body mass index in the general population and predisposes to adult and childhood obesity" by Frayling, T. et al; Science, published in advance online 12 April 2007.

The Wellcome Trust is the largest charity in the UK. It funds innovative biomedical research, in the UK and internationally, spending around £500 million each year to support the brightest scientists with the best ideas. The Wellcome Trust supports public debate about biomedical research and its impact on health and wellbeing. http://www.wellcome.ac.uk

For further information, please contact:

Siân Halkyard
Acting Head of Communications
Queen Mary, University of London
Tel: +44 (0) 20 7882 7454
email: s.halkyard@qmul.ac.uk

Notes to Editors:

Queen Mary, University of London

Queen Mary, University of London is one of the UK's leading research-focused higher education institutions with some 15,000 undergraduate and postgraduate students.

Amongst the largest of the colleges of the University of London, Queen Mary’s 3,000 staff deliver world class degree programmes and research across 21 academic departments and institutes, within three sectors: Science and Engineering; Humanities, Social Sciences and Laws; and the School of Medicine and Dentistry.

Queen Mary is ranked 11th in the UK according to the Guardian analysis of the 2008 Research Assessment Exercise, and has been described as ‘the biggest star among the research-intensive institutions’ by the Times Higher Education.

The College has a strong international reputation, with around 20 per cent of students coming from over 100 countries.

Queen Mary has an annual turnover of £220 million, research income worth £61 million, and generates employment and output worth £600 million to the UK economy each year.

Queen Mary, as a member of the 1994 Group of research-focused universities, has made a strategic commitment to the highest quality of research, but also to the best possible educational, cultural and social experience for its students. The College is unique amongst London's universities in being able to offer a completely integrated residential campus, with a 2,000-bed award-winning Student Village on its Mile End campus.

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