The boy who could walk on hot coals

The life and death of a young street performer from Pakistan who could
walk on hot coals and drive knives through his arms without flinching
has led scientists to a genetic discovery that could revolutionise the
treatment of pain.Scientists at Cambridge University began studying the
child to understand why he was unable to feel pain, but was otherwise
completely healthy. He died shortly before his 14th birthday, from
injuries sustained after jumping off a roof while playing with
friends.The scientists broadened their investigation to three families
related to the child and found that none had experienced pain at any
time in their lives.

All six family members had bruises and cuts and most had fractured
bones. Two were missing the front third of their tongues after biting
themselves in childhood. The way in which the young street performer
died also highlighted the importance of pain as a built-in defence
mechanism to stop people damaging themselves.Detailed neurological tests
on the families, all of whom originated in northern Pakistan, revealed
they responded normally to touch, temperature, tickling and pressure and
had no signs of nerve disease. An explanation for the rare condition
only became apparent when a team of scientists led by Geoff Woods, a
medical geneticist at Cambridge, conducted extensive genetic tests that
revealed they all carried an extremely unusual mutation in a single
gene.

The defect, in a gene called SCN9A, disrupts the flow of sodium ions in
specific nerve fibres that sense damage. The results of the research are
published on Thursday in the journal Nature.John Wood, a neurobiologist
at University College London and co-author of the study, said: "The
mutation means that the very first stage of that electrical signal is
lost, so the pain signal doesn't reach the brain." Scientists have
previously written about people who do not feel pain, but in all other
cases they suffered other medical problems because of the damage to
their nerves.Woods, from the University of Cambridge institute for
medical research, said: "This paper shows that rare diseases can still
be of great importance because of the insights they give into biological
and developmental processes."The researchers included a number of
investigators from Pakistan and other United Kingdom institutions.
The work, which was carried out with the drug company Pfizer, paves the
way for a new approach to managing pain, the scientists believe.They
hope drugs that block the same biological pathway affected by the
mutation will yield new and potentially safer pain medications."This
gives us an excellent target to develop painkillers, because we know
that if we can block this sodium channel, you will lose the perception
of pain, but it will not affect you in any other way," said Wood.
"Potentially this is as important as the identification of the morphine
receptors.

It is fascinating that this same gene, when mutated to encode a
hyperactive channel, has also been found to contribute to ongoing pain
in some heritable human disorders." -- Guardian