Doctors have identified a new mutation in a woman who is barely able to feel pain or stress after a surgeon who was baffled by her recovery from an operation referred her for genetic testing.
Jo Cameron, 71, has a mutation in a previously unknown gene which scientists believe must play a major role in pain signalling, mood and memory. The discovery has boosted hopes of new treatments for chronic pain which affects millions of people globally.
Cameron, a former teacher who lives in Inverness, has experienced broken limbs, cuts and burns, childbirth and numerous surgical operations with little or no need for pain relief. She sometimes leans on the Aga and knows about it not from the pain, but the smell.
But it is not only an inability to sense pain that makes Cameron stand out: she also never panics. When a van driver ran her off the road two years ago, she climbed out of her car, which was on its roof in a ditch, and went to comfort the shaking young driver who cut across her. She only noticed her bruises later. She is relentlessly upbeat, and in stress and depression tests she scored zero.
In a case report published on Thursday in the British Journal of Anaesthesia, the UCL team describe how they delved into Cameron’s DNA to see what makes her so unusual. They found two notable mutations. Together, they suppress pain and anxiety, while boosting happiness and, apparently, forgetfulness and wound healing.
The first mutation the scientists spotted is common in the general population. It dampens down the activity of a gene called FAAH. The gene makes an enzyme that breaks down anandamide, a chemical in the body that is central to pain sensation, mood and memory. Anandamide works in a similar way to the active ingredients of cannabis. The less it is broken down, the more its analgesic and other effects are felt.
The second mutation was a missing chunk of DNA that mystified scientists at first. Further analysis showed that the “deletion” chopped the front off a nearby, previously unknown gene the scientists named FAAH-OUT. The researchers think this new gene works like a volume control on the FAAH gene. Disable it with a mutation like Cameron has and FAAH falls silent. The upshot is that anandamide, a natural cannabinoid, builds up in the system. Cameron has twice as much anandamide as those in the general population