CNIO researchers find a genetic variant that predisposes to thinness and is carried by 60% of Europeans

Researchers from the National Cancer Research Center (CNIO) and the IMDEA Food Institute have discovered

whose carriers tend to accumulate less fat, and it is estimated that it is present in almost 60 percent of the population European.

Their work is published in the journal 'Genome Biology', with Nerea Deleyto Seldas (CNIO) and Lara P. Fernández, from the IMDEA Food Institute, as first co-authors.

For the head of the Metabolism and Cellular Signaling Group at the CNIO, Alejo Efeyan, "the finding represents a further step in understanding the genetic components of obesity".

Ana Ramírez de Molina, director of the IMDEA Food Institute, considers that "knowledge of the implication of the cellular detection pathway of nutrients in obesity may have implications for the development and application of personalized strategies for the prevention and treatment of obesity".

For

, according to studies that in recent years have analyzed the entire genome of tens of thousands of people.

In other words, "lifestyle, such as eating habits and exercise, have a great impact, but genetic factors also have an influence", explains researcher Nerea Deleyto Seldas, from the CNIO.

Overweight and obesity are defined by an abnormal or excessive accumulation of fat that affects health.

To search for genetic variants that influence the phenomenon and the associated metabolic alterations, a team from IMDEA Food collected genetic material from 790 healthy volunteers and data such as weight, BMI, amounts of total and visceral fat, amount of muscle mass and waist and hip circumferences, among others.

The authors of the work analyzed the possible associations of these parameters with 48 specific genetic variants, selected for their possible functional relevance.

They thus detected a "significant correlation between one of these variants in the FNIP2 gene, and many of these parameters related to obesity," explains the study.

then studied in mice

-which had previously been genetically modified to express it-.

"We found that mice with this variant, associated in people with a slim build, have between 10 percent and 15 percent less fat than their non-carrier counterparts," explains Efeyan.

In humans, the effect of this variant cannot be isolated from that of many other genetic and environmental variables that influence physical constitution, so it is impossible to accurately calculate the power of its effect.

But since the influence of genetics on obesity is no more than 20 percent, the contribution of the now-identified variant is necessarily small.

That

"It is not at all that those who have this version can eat in excess without gaining weight," says Efeyan.

Thus, the genetically modified animals for this study did not present other alterations or differences.

"This result is very impressive, because many of these studies usually limit themselves to reporting associations; in this work we show that the change of a single letter in the entire mouse genome is enough to replicate what is observed in the human variant", continues Efeyan.

The importance of the variant detected lies in the fact that it is associated with the biochemical signal pathway that tells the cell what nutrients are available.

According to the researchers,

The goal in the future is "to better understand the molecular bases of what this genetic variant does, that is, what is happening to the cell biochemically," adds Deleyto.

"We need to improve genetic tools to dissect when the functional consequences of this variant become important in the organism, for example, during the process of fat formation," he stresses.

The finding also raises questions that concern other areas of science, such as what evolutionary pressures favored the selection of this variant and when it occurred.

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