Congenital insensitivity to pain (CIP) is an extraordinarily rare condition in which a person cannot feel and has not felt physical pain. This hereditary disease affects nerves controlling sensation such as pain and autonomic nerves that control biological functions, like sweating. In one category, the nervous system fails to develop, while analgesia (meaning from birth), the nervous develops, but does not function.Neurotypically, we move away when something feels hot to the touch. That is because the sensory receptors on the pads of our fingers and palms send a signal through our arm muscles and to the brain and spinal cord where the connection can be made. Thus, we pull our hand away quickly from something sharp or hot. The lack of pain awareness often leads to wounds, bruises, broken bones, bleeding, and a plethora of other serious and life threatening issues that may go unnoticed. CIP results in a mutation in the SCN9A gene that encodes a protein called Navl.7 that is essential for initiating pain signals between neurons. Interestingly enough, people with this rare disease also can lose their sense of smell, which is called anosmia. This is due to the fact that the disease affects the peripheral nervous system, which incorporates sensations such as touch, smell, and pain.
CIP can also occur due to use of certain drugs or medications such as tricyclic antidepressants and narcotics. In addition, this disease can develop in utero due to toxins affecting the developing baby.
Although individuals with this disease can feel a difference between something that is hot cold, rough and soft, or sharp and dull, it is the degree of sense that they lack; Drinking a hot beverage and not knowing that they burnt their tongue. There is currently no cure for CIP/A, however there are lifestyle changes that people can make to be safe and avoid injuries.