Neanderthal genes may explain potentially deadly disorder where the brain bulges out of the skull
Neanderthal The fact that we have maintained ourselves with our ancestors can have transmitted DNA which makes that some people develop a potentially fatal condition where the brain derogates from the skull, according to a new study.
The disorder, known as Chiari type I malformation, affects the lower part of the cerebellum, the part of the brain that helps control movements. In people with this condition, the cerebellum exceeds through the hole at the base of the skull and in the spine. Symptoms may include headache, neck pain and dizziness, and so too brain Swelling, it can be fatal.
In light cases, symptoms can be treated with muscle relaxants, while in serious cases, doctors can treat the disease by eliminating pieces of bone from the breakage or vertebra, Mark CollardA paleoanthropologist at Simon Fraser University in British Columbia, told Live Science.
Discovered in the 1800s by the Austrian pathologist Hans Chiari, the disorder would affect approximately 1 person in 1,000. However, research on recent imaging suggests that it can be much more common, potentially occurring in more than 1 people in 100 – it’s just that most cases escape an opinion because they do not show major symptoms, said Collard.
Type 1 chiari malformation occurs when the occipital bone at the back of a person’s skull is not large enough to keep the brain correctly, leading the domed portion to pinch. However, it remains uncertain which means that the occipital bone is unusually small.
In a 2013 studyscientists proposed that the condition was the consequence of crossing Between the Neanderthals and modern humans in Eurasia. Previous research has revealed that such a mixture has led the genomes of all non-Africans to contain 1.5% to 2% DNA.
In relation: ‘More Neanderthal than human’: how your health can depend on the DNA of our ancestors lost for a long time
Modern human skulls are globular, with a rounded back of the skull, while the Neanderthal skulls were relatively elongated, with a more angular back of the skull. The 2013 study suggested that Neanderthal DNA could influence the modern development of human skull, leading to a gap between the size and shape of the brain and the skull – in particular the base of the skull.
To explore this idea, the new study examined 3D CT scans Skulls of 103 living people – 46 with disorder, and 57 without. The researchers compared these skulls to eight fossil skulls of close relatives of modern humans, including the Neanderthals, Homo heidelbergensis,, Homo erectus and prehistoric Homo sapiens.
Principal author of the study Kimberly PumpOsteologist at the University of the Philippines Diliman, and his colleagues found that the skulls of modern humans suffering from disorder were more likely to the Neanderthal than people without malformation. All the other fossil skulls were more similar to modern humans without disorder.
“Our study can mean that we are one more step to obtain a clear understanding of the causal chain which gives birth to the type 1 chiari malformation,” said Collard, co-author of the study. “In medicine, as in other sciences, the clarification of causal channels is important. The clearest can concern the causal chain resulting in a medical condition, the more you can manage, even solve the condition.”
The Collard underlines these results do not definitively prove a link between this disorder and the Neanderthal genes. “Scientific research is rarely, or never, on the basis of a single study,” he noted.
Future work could analyze more skulls, in particular fossils, said Collard. Researchers can also focus on collecting African data. “What we know about the occurrence of Neanderthal DNA in the pool of living human genes suggests that we should expect a higher prevalence of type 1 chiari malformation in Europe and Asia in Africa,” said Collard.
If future research confirms a link between Neanderthal genes and this disorder, “then it could be logical to add screening for these genes to early childhood health assessments,” said Collard. In this way, people with a higher risk of the average to develop a type 1 chiari malformation could be identified and then monitored and managed by health professionals.
Scientists detailed their conclusions on June 27 in the journal Evolution, medicine and public health.
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