Twins' pain sensitivity varies more than thought
Findings could guide search for better chronic pain treatments
Our pain sensitivity could be changed by lifestyle and environment influences throughout life, a genome study on identical twins suggests.
Researchers used 25 pairs of identical twins in the U.K. to look for "epigenetic" differences in the expression of a gene associated with pain tolerance to heat. They said the findings in Tuesday’s issue of the journal Nature Communications could guide the search for better pain relief treatments for people with chronic pain.
"Epigenetic switching is like a dimmer switch for gene expression," said study author Tim Spector, a professor of genetic epidemiology at King's College London.
The study "shows how identical twins, when combined with the latest technology to look at millions of epigenetic signals, can be used to find the small chemical switches in our genes that make us all unique — and in this case respond to pain differently," he added in a release.
In the study, each twin had a heat probe put on their arm. When the heat became too painful, they pressed a button so researchers could tell what their pain threshold was.
For the first time, the researchers said they found a pain sensitivity gene, called TRPA1, can be switched on and off through chemical changes at an epigenetic level.
Drug companies developing painkillers have their sights set on TRPA1. The study also revealed "compelling candidate genes for pain sensitivity."
The study’s authors confirmed the twin findings by examining the genomes of 50 unrelated individuals.
The research was funded by the European Research Council and academic grants from Pfizer Inc. and the Wellcome Trust, as well as both Guy's and St Thomas' Charity and the National Institute for Health Research, and King's College London.