- Click to share on Facebook (Opens in a new window)
- Click to share on Twitter (Opens in a new window)
- Click to share on LinkedIn (Opens in a new window)
- Click to email a friend (Opens in a new window)
How do you know if you are obese or overweight? 2:14
(CNN) - We all know who they are: They can eat as much as they want, spend zero time in the gym and not gain weight.
Now, according to new preliminary research published Thursday in the journal Cell , scientists may have discovered the gene that helps these super skinny people stay so thin, potentially opening a new frontier in treatments to combat obesity.
An international team of scientists said they have identified a unique genetic variant for lean individuals in what is known as the ALK gene. The ALK gene produces a protein called anaplastic lymphoma kinase, which is involved in cell growth.
They identified the variant after looking at DNA samples and clinical data from more than 47,000 healthy people in Estonia between the ages of 20 and 44.
"The Estonian biobank is very unique in its details," said lead author Josef Penninger, a professor in the department of medical genetics and director of the Institute of Life Sciences at the University of British Columbia.
"We looked at the genetic maps of people with a BMI [body mass index] below 18 and compared them to those of people of normal weight and found the [genetic variant] that correlated with being super-thin," Penninger said.
The team then examined how the ALK gene works in mice and flies.
Stephen O'Rahilly, professor and head of the department of clinical biochemistry and director of the metabolic diseases unit at the University of Cambridge, said the research "was not definitive" but "very interesting."
O'Rahilly, who was not involved in the study, added that "it certainly increases interest in ALK7 inhibition as a therapeutic strategy for treating obesity."
LOOK : Why does obesity potentiate the severity of covid-19?
Thinner flies and mice
Scientists already know that a mutated form of the ALK gene and protein can boost the development of cancerous tumors, according to the study. Mutated forms of the gene and protein have been found in non-small cell lung cancer, anaplastic large cell lymphoma, and neuroblastoma, a brain cancer.
This new finding suggests that a different gene mutation may play a role in thinness and resistance to weight gain. To test this, the scientists conducted experiments on flies and mice and found that deletion of this gene resulted in thinner versions of those flies and mice.
"We gave the mice (which was equivalent to) a McDonald's diet. Normal mice became obese and those without ALK remained slim, "said Penninger.
The team's mouse studies also suggested that the ALK gene instructs fatty tissues to burn more fat from food.
O'Rahilly described the animal studies as "well done," but noted that the genetic variation associated with the lower body mass index in the Estonian biobank was "modest" and not as robust as many experts in the field would accept as " definitive ”.
However, he said that previous studies in much larger populations have shown a suggestive, but not strong, sign of an association with body weight in that area of the genome, and the variation was unlikely to be unique to Estonians.
Penninger said treatments targeting the gene could help scientists fight obesity in the future.
"If you think about it, it's realistic that we can turn off the ALK and reduce the ALK function to see if we stay slim," said Penninger.
"ALK inhibitors are already used in cancer treatments. You can point there. We could possibly inhibit ALK, and in fact we will try to do so in the future. ”
Thinness
