Congenital Insensitivity to Pain (CIP) is technically classified as a peripheral neuropathy. Basically meaning you have damage to, or a disease affecting, your nerves. This rare condition leaves it’s sufferers without the ability to feel pain. It might seem like a blessing, never to perceive pain. Going through life seemingly indifferent to all the damage our bodies take, while becoming the master of any Slap & Tickle game you create. The reality however is quite different. The side effects usually leave a person with life-long crippling problems.
Pain, in general, is a major health concern. It’s estimated we spend at least $560 billion dollars annually in the United States trying to rid ourselves of this debilitating stimulus. Without it, however, we would lose motivation to protect ourselves from damaging situations, while simultaneously encouraging us to avoid similar problems in the future. Furthermore, we would never have the desire to protect affected body parts while they heal.
Infants born with CIP have been known to damage themselves unintentionally. Chewing their tongues, cheeks or hands leading to countless lesions and infections. Scratching their eyes to the point of blindness. Sustaining severe burns while unknowingly touching hot objects.
As a person grows up with the illness, numerous orthopedic complications begin to arise. Bone deformities from untreated fractures. Joint problems known as a Charcot joint. This progressive degeneration of a weight bearing joint is caused by frequent bone destruction and resorption that can lead to malformations, loss of function, and sometimes amputation.
CIP sufferers also widely report the inability to smell, known as anosmia. In the end, the seemingly unpleasant stimulus of pain is quite essential to life as we know it.
Currently there are 3 known genes with 28 mutations that can lead to a diagnosis of CIP. All of which revolve around either how nerves transmit pain signals, or the total number of nerves present.
Neurons responsible for painful stimuli need voltage gated sodium channels to generate nervous impulses that can notify the brain of pain. It’s no surprise then, the first gene to be discovered affecting CIP patients is known as SCN9A. Mutations of this gene produce non-functioning sodium channels, so painful stimuli sensed by a nerve never reach the brain.
Another gene, SCN11A also affects sodium channels. Instead of producing inactive sodium channels, mutations of this gene cause them to become over-active. The result is interference with the nerve fibers ability to produce and send impulses to the brain.
In 2014, researchers found yet another gene associated with CIP. Called PRDM12, it’s located on the long arm of chromosome 9. While mutations of SCN9A and SCN11A result in nerve fibers that don’t send pain signals, mutations of PRDM12 result in no pain fibers being developed at all.
PRDM12 is like a master control gene. Specifically known as a transcription factor, it regulates the actions of other developmental genes causing them to be either activated or deactivated. It does this by affecting a protein called chromatin. Since chromatin is known to play an important role in the development of nerve cells, it’s no surprise that a mutation of this gene can lead to abnormal amounts of nerve fibers in any given area.
When researchers examined biopsies of 11 unrelated families with different PRDM12 mutations, they found several had no nerve endings whatsoever in their legs. Some had nerve endings with half the normal number of pain sensing fibers.
Fortunately, CIP is extremely rare. To date only about 20 cases have ever been reported in scientific literature. So rare that Dr. Stephen Waxman, director of the Center for Neuroscience and Regeneration Research at Yale University School of Medicine, states; “the disease is so rare that doctors do not have a lot of advice on how to deal with it day-to-day…….. I think we doctors need to work with [these patients] and educate them and we need to learn more about this disorder so in the future we can come up with definitive and effective treatment.”
For those parents who have a child affected by CIP, there is help out there. Tara Blocker, mother of Ashlyn Blocker, a CIP patient, founded Camp Painless but Hopeful in 2011. The goal being to bring together patients and family’s living with CIP to bring awareness to the rare disease. The camp also gives crucial resources of information by gathering parents together and sharing in their common problems.
So the next time you’re lying in a hospital bed cursing the nurses because they won’t bring you enough medicine to sooth your aches and pains, take comfort you have the ability to know you have an injury in the first place. You could have ended up blind from scratching your own eyes out, and cursing how all the food tastes similar because you can’t smell, all the while hoping you don’t end up more deformed than Gumby at a daycare center.