By IANS,
Washington : New genetic variants could trigger fat mass, weight and risk of obesity, a study of 90,000 people conducted jointly by 77 global institutions has said.
For example, rare but highly disruptive variants in the MC4R gene were shown to be responsible for very severe genetic forms of obesity.
“This collaboration has uncovered more common variants that affect more people,” explained Ruth Loos, co-author of the study and a member of the Medical Research Council (MRC) epidemiology unit.
The variants act in addition to the recently described variants of the FTO gene; adults carrying both the variants, on average, are nearly four kg heavier.
“This is a great example of how cooperation can bring about new findings that can be missed when researchers work in isolation,” explains Inês Barroso, investigator at the Wellcome Trust Sanger Institute and another co-author of the study.
“The precise role in obesity of genetic variants in FTO and near MC4R remains to be discovered, but we can now begin to understand the biological consequences of these variants. This is where this research will make a difference,” reports Sciencedaily.
“Through this new and powerful genetic approach we are increasingly finding that the genes known to play a role in severe – but rare – diseases are also implicated in much more common diseases,” explained Mark McCarthy of University of Oxford.
In a study of almost 6,000 children, they found that the effects were almost double those seen in adults. Between the ages of four and seven, this additional increase in weight was the result, almost exclusively, of gain of fat tissue, and not due to gain in muscle or other solid tissues.
This more dramatic effect in young children reflects the more extreme consequences seen with rare variants of MC4R, suggesting that the novel variants do indeed exert their effect through action on MC4R.
“Our work to understand common disease, such as obesity, depends on the participation of thousands of people – members of the public who provide samples,” explained Nick Wareham of the MRC Epidemiology Unit.
The study has been published in Nature Genetics.