The researchers have examined the genes of 5,000 Greenlanders , corresponding to around 9% of the entire population in Greenland. In 4.4% of the test subjects this specific gene was inactive. The study findings were published in the journal Nature Genetics
Associate Professor Niels Grarup said, we have found a gene, ADCY3, which predisposes Greenlanders to obesity and diabetes when it is inactive, this appears to be unique to the Greenlandic population.
The activity of the gene is important because everyone has two copies of all their genes. This means that the gene may be expressed in full, in part or not at all. In around four percent of the Greenlanders the gene is only expressed in part.
On average this increases their weight by two kilos, their waist circumference by two centimeters and their BMI by 1 unit compared to the rest of the population.
And the risk of developing diabetes also increases when the gene is not fully active: 11% of those where the gene is expressed in part of diabetes; the figure is 43% for those where the gene is not expressed at all. Around 7% of all Greenlanders in whom the gene is expressed in full have diabetes.
The researchers were very concerned that this is a Greenlandic gene that causes obesity and the risk of developing diabetes. Because in 7 individuals the gene is not expressed at all, and this really causes problems.
On average it increases their weight by 15 kilos, their waist circumference by 17 centimetres and their BMI by seven units, of course with some statistical uncertainties, as we are talking about a very small number of people.
The study is further supported by previous research results, as tests on mice have shown that increasing the activity of the gene causes the mice to become slender and develop a well-functioning metabolism. Thus, they do not develop overweight and diabetes, even if they are given to fat diet.
'These findings pave the way for more studies of if this knowledge can be used to develop new drugs, which may also be used elsewhere in the world. At any rate, we have several clear indications that expression of this gene is closely connected with obesity and diabetes', said, Torben Hansen.
Greenlanders in whom this gene is not expressed at all. But when we look at a group of 140,000 Europeans we are unable to find a single person in whom the gene is not expressed. This means that this is strongly over-represented in Greenland, Niels Grarup explained.
The genetic variation may have been over-represented in the Greenlandic population, because it has been genetically cut off and isolated from other populations for several thousands of years. In the future the researchers will explore the possible positive effects of activating the gene.