This pathology of the hand inherited from Neanderthal

Do you know Dupuytren’s disease? Unless you are one of the 10% of people in Europe or Japan who suffer from this pathology, it is very likely that the answer will be negative. Because even those who present its initial forms often pay little attention to the few nodules that emerge under the palm of their hand.

When the disease progresses, on the other hand, it is difficult to miss it. The thickening of the aponeurosis, the appearance of cords on this membrane which separates the tendons and the skin, leads to an irreducible flexing of the fingers – often the ring finger. But as these symptoms mainly occur after the age of 60, or even much later, they are sometimes, again, neglected.

The disease has been known since 1832 and the discovery by Baron Guillaume Dupuytren, a military surgeon by trade, of a deformity in his coachman’s hand. For this reason, it will long be called the “coachman’s disease”.

A genetic dimension

However, nearly two centuries later, the cause of this fibrosis is still unknown. Dupuytren and his successors have only just highlighted various risk factors: age first, sex (it affects men more), alcohol consumption, diabetes or even the multiplication of microtraumas of the hand.

Doctors have also identified a genetic dimension to this condition. A Danish study conducted on twins showed that the “heritability rate” reached 80%, in other words, if one of the twins is affected, there is an 80% chance that the other will be too. As the disease appeared to be overrepresented in Scandinavia, with 30% of men over 60 affected in Norway, it earned a new nickname: “Viking disease”. And too bad if genetic studies have exonerated the Nordic fighters.

In truth, it is towards other powerful cousins, who disappeared around 40,000 years ago, that we will have to turn our gaze. A team led by the Swedes Hugo Zeberg (Karolinska Institute) and Svante Paabo (Max Planck Institute) has just shown that two of the three essential genetic risk factors had been transmitted to us by Neanderthal man. Their results were published on Wednesday June 14 in the journal Molecular Biology and Evolution.

A heritage unequally distributed on the planet

Specialists in human genetics are constantly discovering the importance of past and extensive exchanges between sapiens and Neanderthal. This progress has, moreover, partly earned Svante Paabo his Nobel Prize for Medicine in 2022. We thus know that part of our immune response, but also genetic factors of vulnerability to depression, certain addictions, or still risks of contracting a serious Covid-19 would come from variants inherited from our solid cousin.