Jo Cameron only realises her skin is burning when she smells singed flesh. She often burns her arms on the oven, but feels no pain to warn her.
That’s because she is one of only two people in the world known to have a rare genetic mutation.
It means she feels virtually no pain, and never feels anxious or afraid.
It wasn’t until she was 65 she realised she was different – when doctors couldn’t believe she didn’t need painkillers after a serious operation.
When she had surgery on her hand, doctors warned her she should expect pain afterwards.
When she felt nothing, her anaesthetist – Dr Devjit Srivastava – sent her to pain geneticists at University College London (UCL) and Oxford University.
After tests, they found