Doctors discover a gene for pain
15 December 2006
Ever wished you didn't feel pain? Doctors have discovered four families who don't, and have tracked this trait down to a single gene. Now the researchers hope their finding could lead to a new breed of safer painkillers.
Antenna finds out more...
This research was published in Nature on 14 December 2006.
Image: Stock.XCHNG/matchstick
Pain may be unpleasant, but it's an important part of the body's survival strategy. We've evolved to feel pain because it alerts our brain to injuries and protects us against further damage. But some people have a rare condition that means they can't feel pain.
Now doctors have discovered why. By studying four families with children who had never felt pain, they pinpointed a gene responsible. If both parents carried the faulty version of this gene, they could have a child with this condition.
Many of our characteristics are given to us by our parents through genes, made up of DNA.
The families, all from northern Pakistan, each had one or more children who couldn't feel pain. All of these children had suffered from pain-free cuts, bruises, broken bones or infections caused by accidents.
'One child used to perform "street theatre" where he placed knives through his arms and walked on burning coals, but experienced no pain,' says Geoffrey Woods, one of the lead researchers. 'Sadly he died before his 14th birthday after jumping off a roof.'
Geoffrey Woods, Cambridge Institute for Medical Research, Cambridge University
Image: Geoffrey Woods
But apart from these accidents and undetected illnesses, the doctors found the children were healthy. They could all feel sensations of touch and temperature, they just couldn't tell the difference between painful and non-painful feelings.
'The children appeared to have a normal nervous system - and in particular the nerves that should carry pain signals,' explains Geoffrey Woods. 'Using the families' DNA, we mapped the disorder to a region containing the faulty gene.'
The children couldn't tell the difference between the touch of a pinpoint and cotton wool.
Image: istockphoto.com/Rob Friedman
What was going on? Pain signals are usually picked up by nerve cells and carried through the nervous system to the brain. Several genes help to create these signals. But the faulty gene discovered by Geoffrey Woods' team stops pain signals being created, so the nerves are never triggered.
This computer drawing shows a pain signal being picked up by a nerve cell. In the pain-free children, this signal is never created.
Image: istockphoto.com/Sebastian Kaulitzki
So how could this lead to better painkillers?
Scientists think their discovery could lead to the development of new painkillers that don't cause unwanted side effects. 'Any drugs that block this gene from functioning should give total pain relief,' explains Geoffrey Woods.
In the future, these painkillers could be used as a safer alternative to local anaesthetics or to treat long-lasting pain - an idea that's got the approval of other scientists.
Brain scientist Stephen Waxman says we need to produce better painkillers than the ones we already use. 'There is a need for more effective treatments for pain. Current pain-killers can't help all types of persistent pain.'
But he thinks we probably won't see these new painkillers in use for at least ten years: 'The good news is that the pharmaceutical industry is devoting a lot of research towards drugs that selectively block this gene - but there are still lots of challenges to overcome.'
Stephen Waxman, Yale University School of Medicine, USA
Image: Stephen Waxman