Researchers have discovered the proprioception gene, also called “6th sense”, which allows the brain to locate the body in space.
Close your eyes and visualize where your right hand or left leg is. Take a few steps in front of you. If you do not succeed, it means that you are missing the “6th sense “. That of proprioception. More specifically, you are surely the carrier of a mutation in the PIEZO2 gene that American researchers have just discovered. They publish their work in the New England Journal of Medicine.
Proprioception is a very important meaning in everyday life, especially among gymnasts, dancers or high-level athletes. It is he who allows us to walk blindfolded without falling, to be aware of the position of our body in space. A perception that is sorely lacking in two patients aged 9 and 19 cared for by Dr. Carsten Bönnemann, pediatrician and neuroscientist at the National Institutes of Health (NIH) and responsible for this work.
Disturbed senses
These young girls suffer from a unique neurological disorder. In addition to presenting a very severe scoliosis, they suffer from deformities of the hips, fingers and feet as well as difficulty in walking (see the video). Tests performed at the NIH clinic also suggest that these patients are unaware of their bodies. With their eyes blindfolded, they have great difficulty in following a path or cannot find the hand of a person in front of them. They also seem less sensitive to certain forms of touch. They are, for example, insensitive to the vibrations of a tuning fork or perceive as irritating a gesture which is usually perceived as pleasant.
Despite everything, their nervous system is developing properly. The sensation of pain, itching, heat or cold is still perceived, which means that the sensors on the surface of their skin send the right information to the brain and the brain is able to decipher it.
The proprioception gene
For researchers, the origin of these very particular motor and sensory disorders is necessarily genetic. They therefore decide to sequence their genome to discover the responsible gene. They show that they carry a mutation in the PIEZO2 gene.
According to studies in mice, the latter is found in the neurons responsible for proprioception. “In patients, this version of the gene does not work, which is why their neurons do not detect the touch or movement of their limbs,” comments Dr. Alexander Chesler, one of the authors of the study. .
“Our study highlights the key role of PIEZO2 and the importance of the senses it controls in our lives. Our results establish that it is the gene for touch and proprioception in humans, ”concludes Dr. Bönnemann, who hopes to be able to use this new knowledge to better understand the development of the nervous system and muscles in order to discover new therapies.
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