New research on Greenlandic genes makes it possible to detect and treat diabetes more effectively
One in ten adults over the age of 35 in Greenland has diabetes, and 30 to 40 percent are at risk of developing the disease. Diabetes is one-and-a-half to two times more common in Greenland than in Denmark.
However, the disease does not always behave the same way here as it does elsewhere in the world. This is because Greenlanders carry special genetic variants. Researchers have carried out a large-scale genetic mapping in Greenland for the first time, and the results have already changed the daily lives of several diabetes patients.
“We have discovered that some forms of diabetes in Greenland should not be treated as regular type 2 diabetes. Patients have different needs, and they improve either with different medication or simply through lifestyle changes,” says Marit Eika Jørgensen, professor and director at Steno Diabetes Center in Nuuk.
Gene variant traced back 10,000 years
In the new study, researchers analyzed DNA from more than 6,000 people in Greenland. It turns out that Greenlanders have fewer genetic variants than other populations, but the variants they do have are more widespread within the society.
For example, four percent of the population carry a particular genetic variant that causes severe insulin resistance within muscles. This genetic variant has the technical name TBC1D4 and causes a form of diabetes where the body does not react normally to sugar – and standard diabetes medicine does not work.
“Fortunately, it is a relatively mild form of diabetes,” says Marit Eika Jørgensen.
“Often, all the patient has to do is exercise. Medicine doesn’t work because the body already produces plenty of insulin. We could never have gained this knowledge without conducting the study ourselves, because this kind of insight wasn’t available anywhere else in the world.”
Researchers have traced the TBC1D4 variant back more than 10,000 years. It likely helped people survive in the harsh Arctic climate, where the diet consisted of a lot of fat and protein with very little sugar.
About Marit Eika
Marit Eika Jørgensen, 58 years old.
Professor, chief physician and director at Steno Diabetes Center in Greenland.
Moved to Nuuk as a newly qualified doctor in 1995, working at Queen Ingrid’s Hospital.
Returned to Denmark and obtained a PhD on diabetes in Greenland.
Specialist in endocrinology (hormonal diseases).
Former chief physician and research leader at Steno Diabetes Center in Copenhagen.
Returned to Nuuk in 2021 to join Steno Diabetes Center. Became its director last year.
Mother of three adult sons (34, 32 and 25 years old). The eldest is also a doctor and works in internal medicine at Queen Ingrid’s Hospital.
Craftsmen apply the finishing touches to the brand-new Steno Diabetes Center in Nuuk. Photo: Christine Hyldal
Special Greenlandic diabetes variant
Another major discovery concerns MODY, a hereditary form of diabetes often misdiagnosed as type 2 diabetes.
There are 14 known MODY variants. However, researchers found an entirely new variant in Greenland that would not have been detected with the standard tests conducted in Denmark. This variant requires specialized treatment with an older but effective and inexpensive medication. Patients do not need insulin, since their bodies already produce plenty.
“Typically, these patients are slim, have many family members with diabetes, and become ill at a young age. We now know they require an entirely different treatment than what they would otherwise receive,” explains Marit Eika Jørgensen.
The findings mean doctors can now screen for specific genetic variants and offer more precise treatment. According to Marit Eika Jørgensen, it’s also about avoiding unnecessary worry and overtreatment:
“We can now say to people: ‘You have a genetic variant that runs in your family, and we will keep an eye on you.’ That provides peace of mind.”
Facts:
Diabetes is a disease where the body cannot regulate blood sugar effectively, either because it does not produce enough insulin, or because cells do not respond properly to insulin.
Diabetes is one-and-a-half to two times more common in Greenland than in Denmark.
This is partly due to genetic variants leading to MODY and sugar intolerance linked to TBC1D4.
Inuit populations are more frequently predisposed to these variants because they are a relatively small and historically isolated group.
The original population was about 1,800 people. Starvation, natural disasters, and other challenges kept the population small. Each time this happened, genetic diversity was reduced.
This means Greenlanders have fewer genetic variants than other populations – but the variants they do have are often more widespread within the society.
Some genetic variants exist in Greenland that do not appear in Europe at all.
European gene database
In practice, a genetic test involves sending a blood sample to Copenhagen, where the genetic material is mapped. But the databases used for assessment are international and mainly based on European and Asian populations. This can lead to misdiagnoses and incorrect treatments because indigenous peoples are underrepresented in these databases.
“Partly because few genetic studies have been carried out, but also because people have been concerned about how their samples might be used – or misused. But there’s growing recognition that a lack of representation is a problem, and that as a Greenlander, you’re actually at a disadvantage if you need genetic testing,” she says.
With the new study, it is now possible to build genetic databases for research on obesity, diabetes, and cardiovascular risk factors that better reflect the Greenlandic population.
So why are Greenlanders more prone to diabetes than people in other parts of the world?
“It happens as we age and gain weight – just like elsewhere in the world. But here, some people also have a genetic predisposition that makes them more vulnerable to lifestyle changes,” says Marit Eika Jørgensen.
Is the problem with diabetes in Greenland solved now?
Jørgensen laughs. “Every time we learn more, we also discover how much we don’t know.”
“We are far from the end of the road. We hope our research can lead to better and more targeted treatment in Greenland.”