Researchers have identified three variations of a gene called COMT that influence sensitivity to pain and the risk of developing a chronic pain condition.

These findings could ultimately lead to more individualized pain control strategies.

In the study, the presence of a “low pain sensitivity” variant greatly reduced the risk of developing temporomandibular joint disorder (TMD), but the authors believe that this finding will apply to other chronic pain conditions as well. TMD is a common painful condition of the jawbone joint.

“This is the first demonstration that a genetic variation influences both human pain perception and the risk for developing a chronic pain condition,” lead investigator Dr. Luda Diatchenko, from the University of North Carolina at Chapel Hill, said in a statement.

The study, which is reported in the journal Human Molecular Genetics, involved an analysis of COMT variants and pain sensitivity in 202 healthy female volunteers. The subjects were followed for three years to assess the development of TMD.

The researchers identified “low”, “average”, and “high pain sensitivity” variants of the COMT gene. Different combinations of these variants predicted how sensitive the subject was to painful stimuli in the lab.

The COMT variant also influenced the risk of TMD. The presence of the low pain sensitivity variant reduced this risk by as much as 2.3-fold, the investigators report.

“The findings suggest that pain sensitivity is more trait-like - it is not as subjective as we once thought,” senior author Dr. William Maixner told Reuters Health. Moreover, “there is a genetic basis for that trait and one of the key components relates to genetic variations in COMT.”

“By determining the genetic variants present in an individual with a chronic pain condition, it is going to help us tailor the drug treatments,” Maixner noted. “Such testing may even help us tailor behavioral therapy.”

SOURCE: Human Molecular Genetics, January 2005.