Woman who does not feel pain

By Dr. Ananya Mandal, MDMar 28 2019

A woman has been identified by doctors to be able to withstand pain. Surgeons were surprised to encounter her when they noticed that she made a completely painless recovery after a surgery. They have sent her samples for genetic testing to understand the baffling phenomenon.A case report describing her case history was published this week in the British Journal of Anaesthesia.

Seventy one year old Jo Cameron, a former teacher, was found to have a mutation in an unknown gene which could play a role in signalling mechanism of pain within the body. The gene also plays a role in memory functions and mood, explained the doctors. If more can be known on this, there may be new avenues in pain management.

Cameron from Whitebridge inInverness, has a history of fractured bones, burns, cuts, child birth and several minor surgeries. For all these procedures she needed little or no pain relief medication she said. She is also immune to panic and stress said her doctors. She scored zero on all stress and depression tests said her physicians.

This latest episode began with a hip problem for which she needed X rays. She was being treated by her GP for three or four years for problems with walking. She was not experiencing any pain however. X rays showed that her hip joint was damaged to a great degree and in any other person this should have caused severe pain. She, on the other hand, was immune to the pain.

The surgeons then booked her for a hip replacement surgery. The day after the surgery she needed only two paracetamol (Acetaminophen or Tylenol) tablets for the pain. She also had deformed thumbs due to the extremely painful condition called osteoarthritis. For this she was again operated on both hands. Dr.Devjit Srivastava, who was her main doctor at Raigmore hospital in Inverness was baffled at her ability to withstand these surgeries without feeling any pain. He referred her to a pain specialists at UCL in London.

The team found that there were two main mutations in her genetic makeup. These mutations led to her not feeling pain, stress, depression and anxiety. These mutations also raised her positive feelings and also caused her to forget her pain and aided in wound healing, the researchers speculate.

They explain that the first mutation is common among the general public and it can reduce the activity of a gene called FAAH. They explain that this gene is responsible for making an enzyme that can break down an endogenous peptide called anandamide. Endogenous peptides are special chemicals in the body that are important for pain sensation, memory and mood. If anandamide is broken down in less amounts, it leads to pain-free conditions and a generally better mood. The second mutation was a missing portion of DNA in her genetic make up. This deletion was at a region called the FAAH-OUT.This gene essentially controls the workings of the FAAH gene. When it is deleted, like in Cameron, the control of the FAAH is lost and it becomes inactive. As a result there is an upsurge of anandamide in the body. They noted that Cameron has double the amount of anandamide than normal population.

Cameron’s family shows that her mother and daughter do not carry these mutations. Her son carries the second mutation and thus feels less pain than others.

According to researcher James Cox,“This patient doesn’t have a complete loss of pain sensitivity, but we do see that. When they are young, they typically bite off parts of the tongue, and parts of their fingers because they haven’t learned that it’s dangerous.” He added, “There’s an awful lot we can learn from her. Once we understand how the new gene works, we can think about gene therapies that mimic the effects we see in her. There are millions of people living in pain and we definitely need new analgesics. Patients like this can give us real insights into the pain system.” He explained that this understanding of pain and its mechanism at the genetic level, “might contribute to clinical research for post-operative pain and anxiety, and potentially chronic pain, PTSD and wound healing.”