A life without pain is good, but one with no anxiety is bliss

If Jo Cameron wasn’t a gentle, white-haired grandmother, she could be an Avenger. The former teacher from Inverness meets the superhero criteria. She has a unique genetic mutation (tick), which makes her almost immune to pain (tick). It also means that her body heals unnaturally fast (tick), and that she never panics (tick). All she needs now is a pair of knee-high boots and a tragic backstory.

Mrs Cameron, 71, has a mutation in a previously unknown gene which scientists now believe plays a major role in controlling pain sensitivity and healing. She broke her arm and didn’t notice until it started setting at an odd angle. She gave birth to two children without wincing. (“It was quite enjoyable, really.”) At home, she often burns herself on the Rayburn hotplate and doesn’t realise until her skin begins to smoulder. “I’m vegan, so the smell is pretty obvious,” she says. “There’s no other burning flesh in the house.”

Doctors only noticed this superpower when, aged 65, she had an operation on her osteoarthritic thumbs, to remove some bones and rearrange the tendons. The procedure is famously agonising; yet afterward, she reported almost no pain. Her astonished surgeon referred her to pain specialists at UCH in London, who have now published a report in the British Journal of Anaesthesia. They hope that, by studying her DNA, scientists may be able to devise gene therapies to treat chronic pain.

That would, of course, be a marvellous thing. But immunity to pain isn’t the only desirable aspect of Mrs Cameron’s condition. Her genetic “defect” means that her system is awash with anandamide, a moodaltering enzyme named after the Sanskrit word for “bliss”. Basically, she is cheerful all the time. In anxiety and depression tests, she scores perfect zeros. In the most

stressful situations, she feels no fear. Two years ago, a van drove her off the road: her car rolled over and landed upside down in a ditch. Unfazed, Mrs Cameron climbed out and went to comfort the trembling driver of the van.

“I’m not stupidly high, but I’m always happy,” she says. This condition of permanent contentment is, I would wager, even rarer than a pain-free life. (Although Mrs Cameron is the only person known to have her particular genetic mutation, there are other causes of congenital insensitivity to pain.)

Imagine the relief of never feeling anxious, or inexplicably blue, or convulsed by self-pity. Imagine being the kind of parent – as Mrs Cameron says she was – who didn’t groan and beg for mercy whenever the children woke her in the small hours, but leapt out of bed shouting: “Come on, children!” What a different world it would be, if we all had such jolly genes.

Brexit, one imagines, would be solved in time for tea. (A slap-up one, with cake, because no one would be worrying about their figure.) Extremism would wither on the vine, with no anger or fear to feed off. Or perhaps the opposite would happen? Just as pain exists to stop us hurting ourselves, fear often stops us behaving rashly. Freed from anxiety, we might all behave even more badly: smashing up cars and relationships and international treaties and walking away from the wreckage in a state of perfect complacency.

Mrs Cameron appears to have led an exemplary life. Perhaps it’s best if she hangs on to that happiness gene, for now. With great power comes great responsibility.