CIPA

Congenital Insensitivity to Pain with Anhidrosis, better known by its acronym CIPA, is a rare genetic disorder where the gene for creating the nerve cells that carry pain and temperature sensations is missing. As such, the patient is unable to feel any pain, even that from severe injury, and is also insensitive to extremes of heat and cold. CIPA patients also lack the ability to sweat.
Although the disease does not cause fatalities, CIPA patients suffer from a number of complications. Primary among these is the inability to detect the discomfort that results in most people from fever or heat stroke which is complicated by the fact that sufferers are unable to sweat to lower their body temperature. Most CIPA patients die by the age of three simply from overheating.
Those patients who survive infancy suffer from a number of other complications related to their inability to sense pain. They commonly suffer from untreated ulcerations of the lips, mouth and tongue, dental infections, minor breaks in the bones and other conditions that can lead to infection, scarring and deformities that would cause intense pain in any other person.
New York Times article on Ashlyn Blocker, a 13-year old with congenital insensitivity
CIPA is exceedingly rare, with only 60 recorded cases in the whole of the United States. However, it is more common in homogeneous populations. The number of recorded cases in Japan is 300 - about ten times the per capita rate compared to the U.S
Congenital insensitivity to pain with anhidrois at Wikipedia
Category:Genetics