This genetic pathway controls metabolism by inducing fat cells to control fat or burn it, and if the gene is flawed it makes people fat, the new research found. The MIT-Harvard study showed that a faulty version of the fat gene causes energy from food to be sidetracked and stored as fat instead of burned.
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Researchers may have finally explained how an obesity-promoting gene variant induces some people to put on the pounds.
“Obesity has traditionally been seen as the result of an imbalance between the amount of food we eat and how much we exercise, but this view ignores the contribution of genetics to each individual’s metabolism”, says senior author Manolis Kellis, a professor of computer science and a member of MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and of the Broad Institute.
A single nucleotide variant in the FTO obesity locus disrupts a conserved motif, which has obesity effects, according to a study published online August 19 in the New England Journal of Medicine.
Earlier studies attempted to link the FTO region with brain circuits responsible for appetite or propensity to exercise. Of the participants, half of them carried the FTO gene associated with obesity risk, as well as two specific genes, IRX3 and IRX5. But there’s hope as the new findings may open the door to developing meds that can get fat cells to behave differently. In addition, they found a complete resistance to a high-fat diet. But although the new work “suggests that beige fat is playing an important role in human obesity”, he cautions that it is not yet clear that increasing beige fat can induce weight loss, whether in experimental animals or humans.
The activity of the two types of fats is normally regulated by the FTO gene, when the latter is functioning right.
American scientists have identified how a key “obesity gene” region works, and may have found a way to turn it off, moving a step closer to finding a cure for the condition, which affects 500 million people worldwide. “Instead they dissipated more energy, even in their sleep, suggesting a dramatic shift in their global metabolism”, said Dr. Claussnitzer, in the report by Discovery News. This is how genes cause obesity. White fat is the insulating stuff that builds up around our middles, storing energy rather than burning it. Brown fat, which is found in small pockets around our neck and spinal cord, does the opposite – burning calories to produce heat.
“The uncovered cellular circuits may allow us to dial a metabolic master switch for both risk and non-risk individuals, as a means to counter environmental, lifestyle, or genetic contributors to obesity”, Kellis said. Ireland is now on course to become the most obese country in Europe, according to the World Health Organisation.
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Kellis, however, thinks that now the genetic circuitry for FTO and the IRX genes is established, drugs or treatments can be devised that interfere with it to combat obesity. “This can serve as a model for understanding the mechanistic basis of other non-coding variants in other diseases and traits”.
