A new study suggests humans have six senses read more at here www.spinonews.com/index.php/item/963-a-new-study-suggests-humans-have-six-senses

Taste, smell, vision, hearing, touch and awareness of one's body in space? Yes, humans have at least six senses. A new study suggests that the last one, called proprioception, may have a genetic basis.

Proprioception refers to how your brain understands where your body is in space. When police ask a drunken person to touch their finger to the tip of their nose, they're testing the sense of proprioception.

Previous research in mice has suggested that a gene called PIEZO2 may play a role in this sense. The PIEZO2 gene tells cells to produce "mechanosensitive" proteins. Mechanosensation is the ability to sense force, for example, being able to feel when someone presses down on your skin. It also plays a role in proprioception.

To understand the gene’s, effect in humans, the researchers at the National Institutes of Health (NIH) identified two young patients who had a very rare mutation in the gene. The patients also had joint problems and scoliosis.

According to study, the patients were asked to perform several tests related to movement and balance. In one test, researchers found that the patients had a great deal of difficultly walking when they were blindfolded.

In another test, the patients were asked to reach for an object in front of them, first with their eyes open and then while blindfolded. Researchers found, compared with people who did not have the gene mutation, the patients had a much harder time reaching for the object when blindfolded.

Alexander Chesler, a principal investigator at the National Center for Complementary and Integrative Health, said, the findings suggest that the patients who carry the mutations in the PIEZO2 gene are "touch-blind." The patient's version of PIEZO2 may not work, so their neurons cannot detect touch or limb movements.

However, other parts of the patients nervous systems, were working fine. The patients could feel pain, itch and temperature normally.

The researchers said that the PIEZO2 gene has been linked to genetic musculoskeletal disorders. Indeed, the findings suggest that the gene may be required for normal skeletal growth and development, means the sense of touch and proprioception play a role in skeletal development.