Found, the genetic quirks that increase obesity risk

OBESITY, if you’re unlucky, could really be in your genes.

It has long been argued that some overweight people have a slower metabolism, helping to cause their weight gain.

But the genes which affect it have been difficult to find. Now a study has discovered quirks in DNA which may be more common in some overweight people, including some that could make their metabolism slower.

Being overweight is mainly caused by eating too much, and genes affecting metabolism play a smaller role in the risk of obesity than those determining appetite and feelings of fullness.

Taken on their own, the newly discovered genetic variations probably have little effect on people’s weight. But if confirmed in a larger group of participants, and combined with wider genetic information, they could lead to much more reliable DNA tests showing someone’s risk of obesity.

Scientists, analysing blood samples from 8,809 people in Europe, found 202 regions of genetic code which are linked to metabolism. They looked at metabolites – the molecules produced when the body breaks down food, alcohol or medications.

Among these, 74 were discovered for the first time, and most were found to influence whether a person was obese. Dr Massimo Mangino, lead author of the study from the National Institute for Health Research’s Biomedical Research Centre at Guy’s and St Thomas’ Hospital, said: ‘These findings could lead to people getting an accurate genetic “risk score” for obesity.’

For example, some people were found to have a genetic quirk which ‘dials down’ a gene called Cas9, which possibly affects thyroid function. This would cause them to burn fewer calories on average than others, which may lead to weight gain, although more research is needed to establish this.

The findings are still early but experts hope a clearer idea of the genetic risk of obesity will emerge from data on half a million people’s blood metabolites which has been made available in the UK. More research could help to develop drugs to prevent obesity by blocking genes involved in causing it.

The study is in the Metabolites journal.