Pain geneticists at University College London and the University of Oxford identified two mutations; one in a gene called Faah (Fatty Acid Amide Hydrolase), which is well known to pain researchers and "junk DNA" which they dubbed "Faah-Out", controls the Faah gene and in Ms Cameron switches it off.
Jo Cameron, 71, sought treatment six years ago for a hip problem, which doctors determined was severely arthritic and needed to be replaced, The Independent reported.
And not only does her DNA allow Cameron to avoid physical pain, it also keeps her largely anxiety-free, too.
That meant Cameron did not notice the extent of her health issues.
Jo Cameron only recently found out she has a rare genetic mutation that prevents her from experiencing pain, fear or anxiety. "Once we understand how the new gene works, we can think about gene therapies that mimic the effects we see in her", said Cox. One was a micro deletion (part of a gene was missing) and the other was a mutation in a neighbouring gene that controls pain enzyme FAAH.
Genetic tests revealed that Cameron has two notable gene mutations.
"The findings point towards a novel painkiller discovery that could offer post-surgical pain relief and also accelerate wound healing".
"People with rare insensitivity to pain can be valuable to medical research as we learn how their genetic mutations impact how they experience pain, so we would encourage anyone who does not experience pain to come forward", said James Cox, a senior lecturer at University College London.
(Jo Cameron) Jo Cameron, right, is pictured with her husband and her mother in this undated photo.More news: Earth Hour 2019: Eskom has all the jokes
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All her life, Cameron had scrapes and burns and cuts, but hadn't felt any pain, often only noticing burns until she smelled burning flesh, according to the release.
Pain serves an important goal, of course - it would suck to find out you were on fire because of the smell of your own burning flesh.
Researchers described Cameron as "talkative and happy with an optimistic outlook".
The FAAH gene is well-known to pain researchers, as it is involved in endocannabinoid signalling which is central to pain sensation, mood and memory.
Now, the researchers hope to explore this portion of our genome to help those who suffer from chronic pain and anxiety, according to the paper published in the British Journal of Anaesthesia. "I don't get the alarm system everyone else gets". (PA) The pensioner also reported memory lapses throughout life such as forgetting words or keys.
"I would be elated if any research into my own genetics could help other people who are suffering", expressed the old lady.
"One out of two patients after surgery today still experiences moderate to severe pain, despite all advances in pain killer medications".
And it was yet another reminder that we need less addictive alternatives for chronic pain, said Dr. Stephen G. Waxman, a neurologist at Yale and the author of "Chasing Men on Fire: The Story of the Search for a Pain Gene".
The researchers note that this research could have "immense" implications, as over time the discoveries could lead to better pain management and anxiety treatments. "We hope this could help the 330 million patients who undergo surgery globally every year", Srivastava remarks.