[2] For people with this disorder, cognition and sensation are otherwise normal; for instance, patients can still feel discriminative touch (though not always temperature[3]), and there are generally no detectable physical abnormalities.[9][10] A heterozygous microdeletion in the FAAH-OUT pseudogene of the fatty acid amide hydrolase (FAAH) chromosomal region that is expressed in the brain and dorsal root ganglia together with a common hypomorphic single nucleotide polymorphism in the FAAH gene was identified as the presumptive cause of congenital analgesia in a woman named Jo Cameron.A 2018 study analysed six members of a family with inherited pain insensitivity and identified a "novel point mutation in ZFHX2, encoding a putative transcription factor expressed in small diameter sensory neurons", as the cause.As a therapeutic application, the study further discuses how "the ZFHX2 variant and downstream regulated genes associated with a human pain-insensitive phenotype are ... potential novel targets for the development of new analgesic drugs".[16] Congenital insensitivity to pain is found at an abnormally high frequency in Vittangi, a village in Kiruna Municipality in northern Sweden, where nearly 40 cases have been reported.
A patient and doctor discuss congenital insensitivity to pain