SNPwatch: Common Genetic Variant Linked to Chronic Pain

If you’ve ever stubbed your toe, given yourself a paper cut, or burned yourself on a hot stove, you’re very familiar with the intense — but temporary — feelings of acute pain. Chronic pain, on the other hand, can persist for years, usually precipitated by a significant injury. Older people and those with more extensive injuries are more likely to develop chronic pain following such an event but the risk factors are otherwise not well known.

In a recent study published in the journal Brain, Michael Costigan from the Children’s Hospital in Boston and an international team of scientists searched for genetic factors that might contribute to the development of neuropathic pain(chronic pain following nerve injury) in about 1,350 individuals with European or Jewish ancestry. They found that each copy of a C at was associated with greater pain sensitivity.

Because pain is a complex condition, studies such as this one can be challenging to conduct. Indeed, Costigan’s study comprised several different sub-groups of neuropathic pain sufferers — those with lumbar root pain or sciatica pain following disc herniation, amputees, those with post-mastectomy pain, as well as healthy pain-free individuals. But in all pain groups aside from the post-mastectomy group, the C version of was significantly associated with more severe pain. The study authors are not certain why this SNP was not associated with pain in the post-mastectomy group, but they hypothesize that this group may differ from the others in the underlying causes of pain or in treatment protocols. In the healthy, pain-free individuals, the C version was also significantly associated with increased sensitivity to pain.

Costigan and his colleagues had specifically targeted and other SNPs around the KCNS1 gene based on available data from pain research in mice. KCNS1 codes for a protein that regulates the movement of potassium ions in and out of cells. This function is especially important in nerve cells, which use the relative concentrations of different ions to control the nervous system’s response to environmental and internal signals. Although the C version of alters the resulting KCNS1 protein, it is not known whether this change affects the protein’s function.

Millions of people in the United States suffer from chronic pain of some kind, and research in this area has the potential to impact many. This study identifies a new link between the KCNS1 gene and neuropathic pain, furthering knowledge of genetic factors influencing chronic pain and potentially informing therapeutic strategies. Future research may pinpoint the reason this KCNS1 variant influences pain response and identify additional factors involved in chronic pain.