Scientists find genetic mutation that could make people insensitive to pain

April 3, 2019 0 By FM

Researchers have identified a genetic mutation that made a 71 year-old women feel no pain throughout her life, reported a case published in British Journal of Anaesthesia. The research which was co-led by University College London may help develop new treatments that could relieve patients from chronic pain, reported The Guardian last week.

At the age of 65, Jo Cameron sought treatment for an issue with her hip, which made her walk lop-sided despite of her experiencing no pain. The X-ray report revealed massive deterioration of the joint and she had to undergo hip replacement surgery for which she reported no pain and was only prescribed paracetamol.

Following that she underwent a double hand operation after the doctors noticed that her thumbs were deformed by osteoarthritis. Her pain insensitivity after surgery was diagnosed by Dr Srivastava, Consultant in Anesthesia and Pain Medicine at an NHS hospital, Scotland and co-lead author of the paper. The surgery was described as “excruciating” by Dr. Srivastava.

Noticing her condition, she was referred to pain geneticists at UCL and the University of Oxford, who conducted genetic analyses. The researchers were able to find two responsible prominent mutations.

The first was a more common mutation which dampens down the activity of a gene called FAAH. The gene which makes the enzyme FAAH is crucial for breakdown of anandamide, a chemical that is involved in pain sensation, mood and memory. The less anandamide gets broken down, the more will be its analgesic effect.

The second mutation showed a microdeletion of a nearby, previously unknown gene that seemed to be an FAAH pseudo gene which the scientists named FAAH-OUT. The gene was found to be expressed in a wide range of tissues, including fetal and adult brain, and in dorsal root ganglia. Researchers considered the mutation in FAAH-OUT to have a control effect on FAAH gene which became silent with the mutation.

Further tests by collaborators at the University of Calgary, Canada, revealed elevated blood levels of neurotransmitters that are normally degraded by FAAH, which showed evidence for a loss of FAAH function.

Her anxiety scale tests also revealed a zero score on 21 and her depression was scored zero on 29 scale in recent evaluations.

“We found this woman has a particular genotype that reduces activity of a gene already considered to be a possible target for pain and anxiety treatments,” said a lead researcher, Dr James Cox in report published by UCL Medicine.

Cameron, who realized her condition in her 60’s, revealed that her lifelong history of cuts, burns or injuries tend to heal quickly and sometimes had gone unnoticed immediately.

“We hope that with time, our findings might contribute to clinical research for post-operative pain and anxiety, and potentially chronic pain, PTSD and wound healing, perhaps involving gene therapy techniques,” said Dr Cox.

“One out of two patients after surgery today still experiences moderate to severe pain, despite all advances in pain killer medications and techniques since the use of ether in 1846 to first ‘annul’ the pain of surgery. There have already been unsuccessful clinical trials targeting the FAAH protein — while we hope the FAAH-OUT gene could change things particularly for post-surgical pain, it remains to be seen if any new treatments could be developed based on our findings.”