Plump or puny, it’s two sides of same genetic coin, experts say

Being naturally overweight or skinny could be two sides of the same genetic coin, new research suggests.

Scientists have discovered that underweight people possess extra copies of certain genes. Previously, the issue of missing identical genes was linked to obesity.

Last year, the same research team found that people with the gene deletions were 43 times more likely to be clinically obese.

Chief scientist Professor Philippe Froguel, from the School of Public Health at Imperial College London, said: “It’s the first example of a deletion and a duplication of one part of the genome [genetic code] having opposite effects.

“If we can work out why gene duplication in this region causes thinness, it might throw up new potential treatments for obesity and appetite disorders.”

The genes involved would now be studied further, he said. A study of DNA from more than 95,000 people revealed that duplication of part of chromosome 16 was associated with being underweight. The abnormality affected one in 2,000 people, making men 23 times and women five times more likely to be extremely thin.