A Pakistani teenager who entertained street crowds by walking on hot coals and sticking knives through his arms has led scientists to find a genetic defect that renders its carriers unable to feel pain.
Scientists at the University of Cambridge in England pinpointed the cause: a defect in a gene that codes for a protein on the surface of pain-sensing nerve cells.
They found mutations in a gene for a particular protein called the 1.7 sodium channel. This is a sort of gate that opens and shuts on the surface of the nerve cells. When the gate opens, sodium ions flood into the cell, causing it to fire. In children with the defect, the gate is welded shut. So their pain nerves cannot fire.
A report in the journal Nature details six individuals with the mutation in three related families. They feel no pain, but are apparently normal in every other way, sensing both touch and temperature.
Pain experts think that if they can find a drug to block the same protein that is disabled in the Pakistani children, it could be the safest and most effective painkiller ever devised.
For now, doctors marvel at the idea there are some people who never know what it's like to hurt. But those with the mutation also can't tell when they break a bone or suffer a cut. As young children, they sometimes injure themselves without knowing. But they eventually learn to compensate.
But pain teaches crucial lessons about danger -- and people with the pain-blocking gene may not learn those lessons. The Pakistani street performer who led to to the discovery died before his 14th birthday, after falling from a roof.