Children with this condition often sustain self-inflicted damage, both in and around the oral cavity (such as having bitten off the tip of their tongue) or fractures to bones.

is an inability for a person to feel physical pain due to various rare genetic conditions. CIP is caused by genetic mutations that affect the development or function of nociceptors, the sensory neurons responsible for recognizing tissue damage.

For people with this disorder, cognition and sensation are otherwise normal; for instance, patients can still feel discriminative touch (though not always temperature), and there are generally no detectable physical abnormalities.

There are generally two types of CIP:
Nociceptors do not develop, meaning that painful stimulus is not even perceived. These are also known as the HSAN disorders.
Nociceptors develop but do not respond to tissue signals, meaning that the patient can perceive the stimulus, but lacks an appropriate response.

In an experimental trial, an opioid antagonist, naloxone, allowed a woman with CIP to experience pain for the first time. This result revealed that opioid antagonists like naloxone and naltrexone may be effective in treating CIP in the future. Additionally, the genes that cause CIP provide promising targets for novel analgesics.