Babies and children * Young people * Weight loss

Genetic link to severe childhood obesity

Zone default image But lifestyle factors still key

A genetic mutation may cause some children to become severely obese, new research has found.

Scientists from Cambridge University say it is the first study of its kind to show that a genetic alteration can cause obesity.

Previously, obesity in children was thought to be solely due to lifestyle factors such as over-eating, lack of exercise and an unhealthy diet.

In the study, DNA from 300 severely obese children was scanned for unique mutations found only in obese children. Their DNA was compared with that obtained from over 7,000 children of a healthy weight.

The scientists discovered that certain parts of the DNA were missing in some patients who were severely obese.

"We found that part of chromosome 16 can be deleted in some families, and that people with this deletion have severe obesity from a young age," said Dr Sadaf Farooqi from Cambridge University.

"Our results suggest that one particular gene on chromosome 16 called SH2B1 plays a key role in regulating weight and also in handling blood sugar levels.

"People with deletions involving this gene had a strong drive to eat and gained weight very easily.

"It adds to the growing weight of evidence that a wide range of genetic variants can produce a strong drive to eat.

"We hope that this will alter attitudes and practices amongst those with professional responsibility for the health and well-being of children."

The findings, published today in the journal Nature, may also affect decision making when it comes to deciding if severely obese children should be taken into care.

Several of the children in the study had been placed on the Social Services "at risk" register because it was thought they were being deliberately overfed by their parents. They have now been removed from the register.

The scientists also said that while genetics may help explain why some people are more likely to gain weight than others, the current obesity crisis is "undoubtedly driven by environmental factors."

More information

Are you obese?

This article was published on Mon 7 December 2009

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