Page last updated at 00:01 GMT, Thursday, 4 February 2010

Morbidly obese 'may have missing genes'

X-ray of morbidly obese person's leg
An estimated 700,000 people in the UK are morbidly obese

A small number of extremely overweight people may be missing the same chunk of genetic material, claim UK researchers.

The findings, published in the journal Nature, could offer clues to whether obesity can be "inherited" in some cases.

Imperial College London scientists found dozens of people - all severely obese - who lacked approximately the same 30 genes.

The gene "deletion" could not be found in people of normal weight.

While much of the "obesity epidemic" currently affecting most Western countries has been attributed to a move towards high-calorie foods and more sedentary lifestyles, scientists have found evidence that genes may play a significant role in influencing weight gain in some people.

It is becoming increasingly clear that for some morbidly obese people, their weight gain has an underlying genetic cause
Professor Philippe Froguel, Imperial College London

The latest study focused on the "morbidly obese", who have a Body Mass Index (BMI) of more than 40, and who are at the highest risk of health problems.

There are an estimated 700,000 of these people in the UK.

'Learning difficulties'

The first clue came by looking at a group of teenagers and adults with learning difficulties, who are known to be at higher risk of obesity, although the reasons for this are not entirely clear.

They researchers found 31 people who had nearly identical "deletions" in their genetic code, all of whom had a BMI of over 30, meaning they were obese.

Then a wider scan of the genetic makeup of a mixture of more than 16,000 obese and normal weight people revealed 19 more examples of the missing genes.

All of the people involved were classed as "morbidly obese", with a BMI of over 40, and at the highest risk of health problems related to their weight.

Most of them had been normal weight as toddlers, but then became overweight during later childhood.

None of the people studied with normal weight had the missing code.

The precise function of the missing genes is unclear, as is the precise nature of the relationship between learning difficulties and obesity - none of the people with the deletions in the wider study had learning problems.

Weight-loss surgery

Professor Philippe Froguel, from Imperial College, said: "It is becoming increasingly clear that for some morbidly obese people, their weight gain has an underlying genetic cause.

"If we can identify these individuals through genetic testing, we can then offer them appropriate support and medical interventions, such as the option of weight loss surgery, to improve their long-term health."

Dr Robin Walters, also from Imperial, said that while this particular set of deletions was rare - affecting some seven in 1,000 morbidly obese people - there were likely to be other variations yet to be found.

"The combined effect of several variations of this type could explain much of the genetic risk for severe obesity, which is known to run in families."

Dr Sadaf Farooqi, from Cambridge University, who collaborated with this research, and was involved in similar research published in December which pointed to another gene flaw which could be linked to obesity.

She said it was likely that a "patchwork" of different genetic variations would eventually emerge to explain more cases of obesity - perhaps by affecting appetite, or the rate at which the body burns fat.

She said: "There is still an important public health message about diet and exercise, but simply blaming people for their obesity is no longer appropriate."



Print Sponsor


SEE ALSO
Overweight elderly 'live longer'
29 Jan 10 |  Health
Obese children 'reject surgery'
12 Oct 09 |  Health
Obesity 'link to same-sex parent'
12 Jul 09 |  Health

RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites

FROM OTHER NEWS SITES
IAfrica.com When genes don't fit - 42 mins ago
Telegraph Darwin's genetic history unlocked - 5 hrs ago
MedWire News Lifestyle intervention program improves global CV risk profile - 9 hrs ago
CBC Some severely obese people are missing a sest of genes, a new study has found. - 11 hrs ago
Times Online Are criminals born bad? - 12 hrs ago



FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC navigation

BBC © 2013 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific