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Medical Video: 10 Rare Diseases That Turn People Into Superheroes
Try pinching your cheeks. No, try harder. Sick?
You might think that not being able to feel pain is a miracle. There will be no tears, there will be no painkillers, no lingering pain. In fact, being unable to feel pain is a dangerous thing.
Pain, for most of us, is a very unpleasant sensation. But this serves an important purpose to warn us of potentially life-threatening injuries. If you step on a piece of glass or bang your head too hard, the pain for forgiveness tells you to get medical help immediately. Then, what if you never feel sick?
The inability to feel pain is called CIP (congenital sensitivity to pain). CIP is a very rare condition - only about 20 cases have been reported in the scientific literature to date.
What is congenital sensitivity to pain (CIP)?
Congenital sensitivity to pain (CIP) is a congenital condition that makes a person unable and never feels pain in any part of their body when injured.
Someone who has CIP can feel different types of touch, sharp and blunt, but they can't feel it. For example, they knew the drink was hot, but could not feel that the boiling water had burned their tongue. Over time, lack of sensitivity to pain can cause accumulation of injuries and health problems that can affect life expectancy.
Ashlyn Blocker, a 16-year-old teenager from Georgia, United States, for example. As a newborn baby, he barely speaks, and when his milk teeth start to come out, he unconsciously chews a large part of his tongue. In his childhood, Blocker burned the skin of his palm on the stove fire, and acted as usual for two days with a broken ankle. He had been invaded and gnawed by a flock of fire ants, dipped his hands into boiling water, and injured himself in many other ways, without ever feeling the slightest bit of pain.
Many people who have innate insensitivity to pain also have a loss of sense of smell (anosmia). In some cases, CIP causes a person's inability to sweat at all. However, living with immunity to physical pain does not make people with CIPA insensitive to emotional pain. They can and will feel emotional stress, such as stress, nervousness, mourning, and exploding anger, like other people.
Before knowing what might be the root cause of CIP, it would be better for us to first understand the pain process.
Where does the pain appear?
The nervous system determines the millions of innumerable sensations that we feel throughout the body, every day. The nervous system consists of the brain, cranial nerves, spinal cord, spinal cord, and other bodies, such as ganglia and sensory receptors. Nerves are modes of messenger from the body to the spine to go to the brain. If your finger is sliced by paper, the signal receptor at your fingertips sends a message of pain to the brain, which makes you react screaming "Ouch!" Or cursing harsh words.
Peripheral nerves are important for you to feel pain. These nerves end up in receptors that feel touch, pressure, and temperature. Some of them end up in nociceptors, who feel pain. Nociceptors send pain signals in the form of electricity in line with peripheral nerves, which then travel through the spine and reach the brain. Myelin is a wrap around the nerves of the brain that helps with the flow of electricity - more myelin, the faster the message reaches the brain.
Nerve fibers that carry the message of pain from nociceptors are of two versions (with or without myelin), which means that the pain message can run on the track sooner or later. The pathway taken by the message of pain depends on the type of illness: severe pain runs in the fast lane, while the pain is lighter in the slow lane. This whole process does not happen to people with CIP.
CIP is considered as a form of peripheral neuropathy because it affects the peripheral nervous system, which connects the brain and spinal cord to muscles and cells that detect sensations such as touch, smell, and pain. But, studies have found that nerve conduction in people with CIPA works fine, so there is no evidence that the message of pain is lost.
Some studies show a decrease in function or even the absence of nerve fibers - either with or without myelin. In the absence of nerve fibers, the body and brain cannot communicate. Message of pain did not reach the brain because no one sent them.
What causes a person to not feel pain at all?
CIP is an autosomal recessive disorder. This means that for someone to have a CIP, he must receive a copy of the gene from his parents. Each parent must have one copy of the mutation gene on the autosomal chromosome, a chromosome that is not related to gender. Autosomal recessive disorder means both parties are carriers of gene mutations that can not show signs and symptoms of the condition.
A number of genes are known to play a role in the risk of someone inheriting CIP. The SCN9A gene is the most common cause. This gene is involved in the transmission of electrical signals in the nerves. Other studies have shown that perhaps the culprit is a mutation in the TRKA gene (NTRK1), which functions to control nerve growth.
In rare cases, CIP can be caused by PMRD12 gene mutations. The PRDM12 gene plays a key role in modifying a protein called chromatin which should be bound to DNA from the chromosome and act as a control switch to activate or deactivate other genes on the chromosome. Chromatin plays a very big role in the formation of nerve cells, so this mutation in the PRDM12 gene can explain why pain-detecting nerves may not be formed correctly in people who cannot feel pain.
