Researchers have identified hundreds of variants in a patient's genetic code that predict which people are more susceptible to persistent chronic pain following amputation.
Dr. Andrew D. Shaw, associate professor of anesthesiology and critical care medicine at Duke University Medical Center in Durham, NC, and colleagues conducted the study on 49 military service members who had amputations and persistent pain.
The International Association for the Study of Pain (IASP) states that 80% of all amputees experience pain in the missing body part - known as phantom limb pain.
Patients complain that the pain is similar to that prior to amputation and is more likely to occur after the amputation of a chronically painful limb.
The IASP explains that large-scale surveys of amputees have revealed that treatments for phantom limb pain are often ineffective, suggesting that they fail to address the underlying mechanisms.
Genetic link to pain response
The new Duke University Medical Center study claims that new DNA sequence variations may be "pathways of biological importance as the possible source of chronic, persistent pain."
Dr. Shaw explains:
"Persistent phantom pain after amputation is a serious problem with no effective treatments. By identifying these 'pain genes,' we may be able to discover the reasons why pain occurs and predict which patients are more likely to have it. In the future, we hope to discover the biology of persistent pain and develop ways to combat it."
The Armed Forces Health Surveillance Center points out that from 2000 to 2011, 5,695 service personnel underwent a total of 6,144 traumatic amputations. And over 30% of these involved a "major amputation" - defined as the loss of a hand, foot or more.
For the study, Dr. Shaw and his colleagues collected DNA, RNA and plasma extractions from blood samples from the 49 service members. They mapped these using Exome Sequencing technology to see if there were any variations common to other members of the trial.
The results revealed hundreds of previously unknown DNA sequence variations.
Presenting their findings at the Anesthesiology 2013 annual meeting this month, Dr. Shaw explained:
"This is one of the first studies where 'pain genes' have been identified in humans using next-generation sequencing. We have known about some of them in lab studies. Now that we have identified these gene variations, we need to study them and then create new medicines to prevent and relieve the chronic pain for these patients."
In 2010, Medical News Today reported mirror therapy had some success treating injured soldiers for phantom limb pain. And in 2012, we reported that a Swiss study identified a genetic component in pain responses from children following major surgery.