Chronic headaches, dizziness, balance disorders or blurred vision affect millions of people around the world. If these symptoms are often attributed to conventional environmental or neurological causes, a recent hypothesis opens an unexpected track: they could be linked to the genetic heritage left by our distant Neanderthal cousins.
This is what a study by Kimberly Plomp and her colleagues at the University of the Philippines Diliman suggests. Published in the journal Evolution, Medicine,
and Public Healththe study is interested in a condition called type 1 chiari malformation, a structural anomaly of the skull which would affect approximately 1 in 100 people. The researchers discovered that the shape of the skull of individuals suffering from this pathology is surprisingly like that of Neanderthals, which could indicate an unsuspected evolutionary origin.
A discreet but impactful anomaly
The malformation of Chiari 1 is a condition in which the lower part of the brain, the cerebellum, sinks abnormally into the spinal canal. This configuration generates compression of the area, causing various disorders: severe headaches, dizziness, numbness, visual or auditory disorders, even motor difficulties. Although this form is considered benign, its effects on quality of life can be significant.
What has intrigued researchers for several years is the particular structure of the skull in people affected. To better understand the origin of this malformation, Kimberly Plomp’s team has analyzed medical scans of 46 adults with the disease and compared them to those of 57 non -affected individuals. From this data, they built precise 3D models of the cranial structures.
Result: the skulls affected by the malformation have a flatter and shorter base, with an occipital bone (the back of the skull) significantly reduced. This creates a space reduced to the junction between the skull and the spinal cord, a configuration which precisely promotes the shift from the cerebellum to the spinal channel.
Benchmarks used in this study, represented on a 3D CT scan of the skull of a living human without CM-I. Credit: Evolution, Medicine, and Public Health (2025). Doi: 10.1093/EMPH/EOAF009
Looking for our skulls
But the study did not stop there. The researchers have expanded their analysis by comparing these modern skulls with those of different ancient human species: Homo sapiens, Homo Erectus, Homo Heidelbergensis… and Homo neanderthalensis.
This is where things become interesting. The form of the skull base of patients with Chiari 1 strongly resembles that of Neanderthals, while that of witnesses aligns more with the anatomy of modern Homo sapiens.
This rapprochement fuels what researchers call the hypothesis of archaic intrrogation: the idea that certain anatomical features, including pathological, that one observes in modern humans could come from genetic crossing with human species today disappeared. We know indeed that people of non -African ancestry have approximately 1 to 2 % of Neanderthal DNA in their genome. A proportion inherited from the interested meetings that occurred about 50,000 years ago.
Neanderthal DNA: vestige or burden?
According to the researchers, the results are consistent with a Neanderthal origin of the malformation of Chiari 1, but do not completely confirm the hypothesis. The anatomical similarities are striking, but the direct genetic proof remains to be established. In other words, the link is plausible, but still speculative.
The next step in the research will therefore be to analyze the genome of patients with this malformation to specifically seek sequences of Neanderthal origin. If such genes are identified, this could not only validate the hypothesis of the introgression, but also pave the way for earlier diagnoses and new treatment strategies.
A reminder on the legacy of evolution
Beyond the medical aspect, this study raises a fascinating question: to what extent are we still influenced by our evolutionary past? The idea that features from ancient human evolution can still affect our contemporary biology reminds us that genetic heritage is not always beneficial.
Useful adaptations thousands of years ago – such as a skull adapted to a robust and physical lifestyle – can be transformed into disabilities in a modern environment, where our larger brains and our permanent standing station require different cranial architecture.
Ultimately, what this study tells us is that our pain today could be the distant echoes of an archaic past. A past inscribed in our, silent but tenacious genes. What if part of our skull illness was literally from the Stone Age?
