doi:10.1038/nindia.2013.136 Published online 11 October 2013
Researchers have investigated a variation in the gene that codes for a protein responsible for re-uptake of serotonin in the gut . They claim that this genetic variation reduces serotonin levels in the gut. Studies have shown that serotonin plays a role in irritable bowel syndrome (IBS). This genetic anomaly could be used to develop a genetic screening test for diagnosing IBS.
IBS is a common chronic gastrointestinal disorder whose symptoms include recurrent abdominal pain, abdominal swelling and altered bowel function. The SLC6A4 gene codes for the serotonin transporter protein, which is responsible for re-uptake of serotonin into gut epithelial cells and neurons. Variations in this gene could alter serotonin levels in the gut, resulting in gut disorders such as IBS. However, previous studies had found conflicting evidence regarding the link between genetic defects and IBS.
Based on knowledge of the functional significance of the serotonin signaling in the gastrointestinal tract, the SLC6A4 variation was considered to be a potential susceptibility factor for IBS. To determine the nature of the relationship between the variation in the serotonin transporter gene and IBS, the researchers analysed the results from 12 previously published studies of Asian and American IBS patients. Their analysis clearly indicates that the SLC6A4 variation is associated with reduced risk of IBS in both Asian and American populations. This genetic variation could thus be used to develop a screening test for IBS risk.