An article this week about Jo Cameron, who has lived for 71 years without experiencing pain or anxiety because she has a rare genetic mutation, prompted questions from New York Times readers.
The notion that the same gene could be responsible for the way a person processes physical and psychological pain left many perplexed: Aren't they totally different? Or does her story hint that sensitivity to one type of pain might be intertwined with sensitivity to another?
Childbirth, Ms. Cameron said, felt like "a tickle." She often relies on her husband to alert her when she is bleeding, bruised or burned because nothing hurts.
When someone close to her has died, she said, she has felt sad but "I don't go to pieces." She cannot recall ever having been riled by anything — even a recent car crash. On an anxiety disorder questionnaire, she scored zero out of 21.
"I drive people mad by being cheerful," she said.
Here's a bit about what's known.