In a recent study published in PLOS Genetics, researchers sought to identify potential genetic links behind chronic back pain causes.
Chronic back pain is the foremost cause of disability worldwide. There is evidence to suggest at least 40% of chronic cases have a genetic component which may predispose individuals to back-pain-inducing conditions. Though genetics are often thought to be the primary cause, genetic factors related to structural changes within the spine – such as the wearing away of the fibrous discs that cushion the vertebra and prevent them from rubbing against one another– only account for a minority of cases of chronic back pain.
The majority of genetically-related chronic back pain causes may involve other, as yet unidentified genetic factors, such as those related to pain sensitivity, pain management, or even mental health. A better understanding of the genetic component of chronic back pain causes could provide avenues for identifying and targeting the root causes of chronic back pain and developing more effective therapies to treat the condition.
In a recent study published in PLOS Genetics, researchers analyzed the genes of over 158,000 European patients, with and without chronic back pain. They collected patient information from 16 databases.
Study identified three gene variants linked to chronic back pain
They found a significant association was found between the SOX5 gene and chronic back pain across databases: those with a certain form of the gene were on average 8% more likely to develop chronic back than their peers. When all datasets were analyzed together, potential, though not statistically significant, associations were also found with variant forms of three other genes, two of which may slightly decrease the risk of chronic back pain (DIS3L2 and DCC) and one which may slightly increase the risk (CCDC26/GSDMC). When one dataset was analyzed separately, those with the variant form of DCC were 3% less likely and those with the variant form of CCDC26/GSDMC were 5% more likely to develop chronic back pain.
Those with the SOX5 variant were more prone to have worn discs in their lower back. Further analysis suggested the variant may lead to a reduction in mechanisms which maintain disc integrity. The CCDC26/GSDMC variant was associated with height, hip bone circumference, and having undergone surgery in the lower back. Further analysis suggested the variant may affect cells related to bone maintenance and structure. The DCC variant was associated with a lower risk of depressive symptoms. The overall contribution of genes to chronic back pain was found to be around 8%.
More research needed to understand how these genes contribute to chronic back pain
Overall, the study identified three gene variants linked to chronic back pain. In addition to supporting established findings of the genetics of disc degeneration, the findings suggest height, hip size, bone maintenance, and depression may play roles in chronic back pain causes.
As the sample population in the databases analyzed were all of European descent, future research among other racial and ethnic groups would provide further insight into the contribution of these genes to chronic back pain. As the definition of chronic back pain varied between databases, with some defining it as back pain lasting 3 or more and others 6 or more months, future research may benefit from analysing both groups separately. In addition, further specifying the type of pain by location(e.g. lower versus upper back) could grant a clearer understanding of how these genes contribute to the condition.
Written by Raishard Haynes, MBS
Reference: Suri, P. et al. (2018). Genome-wide meta-analysis of 158,000 individuals of European ancestry identifies three loci associated with chronic back pain. PLoS Genet 14(9): e1007601. https://doi.org/10.1371/journal.pgen.1007601