The discovery of a gene essential to pain-sensing neurons could leave to the development of new methods of pain relief.

Researchers looked at the genetic make-up of 11 families across Europe and Asia who had an inherited disorder that prevents them from feeling pain, the University of Cambridge reported. The study allowed the researchers to link the cause of congenital insensitivity to pain (CIP) to variants of the gene PRDM12. Family members who were affected by the condition had two copies of the variant, but those who had only one remained unaffected.

Biopsies from the patients affected by the condition revealed specific pain-sensing neurons were absent. PRDM12 has been linked to the modification of chromatin, which is a molecule that attached to the DNA and acts as a "switch" to turn specific genes on and off. Genetic variants of PRDM12 in the CIP patients proved to block the gene's functions. Since chromatin plays an important role in the development of certain neurons, the findings could explain why pain neurons are abnormal in CIP patients.

"The ability to sense pain is essential to our self-preservation, yet we understand far more about excessive pain than we do about lack of pain perception," said Professor Geoff Woods from the Cambridge Institute for Medical Research at the University of Cambridge, who co-led the study. "Both are equally important to the development of new pain treatments - if we know the mechanisms that underlie pain sensation, we can then potentially control and reduce unnecessary pain."

PRDM12 is the fifth gene that has been linked to pain perception, and two previously-discovered pain genes have already been used to develop powerful painkillers.

"We are very hopeful that this new gene could be an excellent candidate for drug development, particularly given recent successes with drugs targeting chromatin regulators in human disease," said Ya-Chun Chen from the University of Cambridge, the study's first author. "This could potentially benefit those who are at danger from lack of pain perception and help in the development of new treatments for pain relief."

The findings were published in a recent edition of the journal Nature Genetics.