Not Viking disease, but Neanderthal disease?
Dupuytren’s Disease and its origins
Dupuytren’s Disease or Dupuytren’s Contracture is a non-contagious condition forcing fingers into a permanently bent position, especially ring fingers and pinkies. Diabetes, some lifestyle choices, and a few medications can predispose people to it. Being older, a man, and with non-sub-Saharan African ancestry are clear risks. Since it was commonly diagnosed in northern European men older than 60, it acquired the moniker “Viking disease.”
The link to Vikings has been controversial. The disease remains prevalent outside of northern Europe, and its genetic markers do not match up with those of Vikings. “Celtic Hand” is another debunked nickname. New research now points to much older origins than the Norse seafarers.
A six-author team, underpinned by 449 others within the FinnGen research project,which combines genetic and digital health data, published a groundbreaking paper in June. In the scientific journal Molecular Biology and Evolution, they explain how Dupuytren’s disease might have originated in Neanderthals.
Neanderthals were a relative of today’s human beings, sharing an ancestor from about 800,000 years ago. Perhaps half a million years ago, the predecessors of Neanderthals left Africa and spread across Europe and Asia. Humanity’s ancestors seem to have stayed in sub-Saharan Africa until about 50,000 to 60,000 years ago. When they moved north, they met Neanderthals and interbred. Various theories from climate change to assimilation by humans aim to explain why Neanderthals went extinct around 40,000 years ago.
Irrespective of why Neanderthals vanished leaving us to dominate planet Earth, they left behind their genes—in everyone outside of sub-Saharan Africa. Up to 2% of the genetic code of people with ancestry outside of sub-Saharan Africa is typically from Neanderthals, compared with usually none in people from sub-Saharan Africa. When the Neanderthal genetic code was mapped in 2010, it opened up huge possibilities to improve understandings of the origins of many genetic variations, including non-infectious diseases.
The new study in June examined genes linked to Dupuytren’s disease, finding 61 genetic variants producing a higher chance of developing the condition. Three of these variants come from Neanderthals, of which two indicate an especially elevated risk.
Overall, 8.4% of the genetic risk is from Neanderthal genes, far higher than would be expected based on the amount of Neanderthal DNA in those who have it. The disease seems to be far more about Neanderthals than Vikings (or Celts), if indeed it ever was about the latter. With human history always involving migration and genetic mixing, it is not surprising that the disease appears in so many places.
Mickey Glantz is a first-generation American living in Colorado. His parents emigrated from Eastern Europe. When his fingers began showing the classic pose, as in the photo of him, doctors told him that it was arthritis.
Eventually, he was diagnosed with Dupuytren’s Disease, the only person in his immediate family known to have it. Some operations helped, but they cannot stop the problems entirely. He asked about options for breaking his finger’s bones and then resetting them. The medical staff did not accept it as a viable treatment.
Mickey cannot touch-type, so his contracted fingers interfere with his life in mainly three ways. He is an avid tennis player and gripping the racket can be more difficult with inhibited fingers. Putting his hands in his pockets is hard, as his fingers stick out. Most dangerous is washing his hair. When he forgets where his fingers are, he pokes himself in the eye.
The Vikings voyaged far and wide, unproven to Massachusetts, but definitely to Newfoundland, Baghdad in Iraq, and Baku in Azerbaijan. Viking DNA would be expected among Eastern Europeans, and, as such, it could readily have reached Mickey. Alternatively, from the new research, his Dupuytren’s Disease could easily—and more likely—have come from Neanderthal genes.
What next? We continue to expand our knowledge about our origins. A new species of ancient humans, Denisovans, was identified in 2010 after completing the gene sequence of bones discovered in Russia in 2008. Mapping DNA across east Asian and Pacific peoples suggests up to 5% of their genes comes from Denisovans.
What diseases and genetic advantages might soon be related to various extinct human cousins?
This article originally appeared in the September 2023 issue of The Norwegian American.