Causes
There are some cases where the condition is caused by increased production of endorphins in the brain, in which case naloxone may be used as treatment. This treatment does not always work. In some cases, this disorder can be in the voltage-gated sodium channel SCN9A (NaV1.7). Patients with such mutations are congenitally insensitive to pain and lack other neuropathies. There are three mutations in SCN9A: W897X, located in the P-loop of domain 2; I767X, located in the S2 segment of domain 2; and S459X, located in the linker region between domains 1 and 2. This results in a truncated non-functional protein. NaV1.7 channels are expressed at high levels in nociceptive neurons of the dorsal root ganglia. As these channels are likely involved in the formation and propagation of action potentials in such neurons, it is expected that a loss of function mutation in SCN9A will lead to abolished nociceptive pain propagation.
Leprosy, an infectious illness, can result in the progressive destruction of the nerves, which can mimic the genetic diseases described above. (Leprosy is a bacterial infection, not genetic, and cannot be passed on to offspring.)
Read more about this topic: Congenital Insensitivity To Pain