April 13, 2007 — British gene hunters said they have found the strongest DNA marker yet for obesity, and one that is very common among most Europeans.
The investigators first identified the gene, FTO, in the DNA of people with type 2, or late-onset diabetes, a condition that is lifestyle-related.
They were surprised to find the marker was associated with increased body fat rather than insulin production, so they scoured other DNA databases to see if the gene predisposed a person to obesity.
The results of that inquiry, the largest such undertaking of its kind to date, revealed that a variant of FTO was closely correlated with obesity, which has emerged as a major public health challenge in many developed nations.
The study showed that half of white Europeans carry one or more variants in their DNA, the researchers said.
Individuals with one copy of the FTO variant had a 30 percent higher risk of being obese than people without it.
In people with two copies of the "fat" gene, the risk rose to 67 percent, and they packed an additional 6.6 pounds in fat on average compared to people without any copies of the allele.
"Our findings suggest a possible answer to someone who might ask 'I eat the same and do as much exercise as my friend next door, so why am I fatter?' There is clearly a component to obesity that is genetic," said professor Andrew Hattersley, of the Peninsula Medical School, Exeter, and study co-author.
It's not clear why the gene predisposes people for increased body fat and higher rates of obesity, but it opens new avenues of investigation for researchers looking into obesity and related problems such as heart disease and diabetes, the researchers said.
