A new study has discovered that irritable bowel syndrome and some psychiatric disorders share common genes, shedding more light on the interaction between the gut and the brain. The findings may lead to new treatments for the common intestinal condition.
Irritable bowel syndrome (IBS) has previously been associated with psychiatric disorders, with studies finding that its comorbidity with these disorders ranges from 54% to 94%. The chronic condition has also been referred to as a psychosomatic illness because it does not present with identifiable pathology on clinical or laboratory examination. Nonetheless, there’s a known genetic component to IBS.
A new study by researchers at the University of Bergen in Norway investigated the genetic underpinnings of IBS and whether there was any connection with mental illness. Using genetic data from 53,400 individuals with IBS and 433,201 controls, they identified 116 new genomic risk loci for the condition. Genomic loci are the specific locations where genes are found on DNA.
The researchers identified 70 unique loci shared between IBS and different psychiatric disorders: seven with generalized anxiety disorder, 35 with major depression, 27 with bipolar disease and 15 with schizophrenia.
Investigating further, they found that there were underlying biological mechanisms common to IBS and psychiatric disorders. Genes mapped to shared loci were enriched for pathways relevant to the nervous and immune systems. Further research is needed to determine the extent to which these mechanisms contribute.
“This expands our understanding of the genetics of IBS and where IBS lies in relation to gastroenterological and psychiatric diseases,” said Markos Tesfaye, lead author of the study. “
While it was beyond the scope of the study to determine if and how intestinal problems led to the development of psychiatric disorders, the researchers offered a possible explanation.
“Some researchers have reported that inflammation in the intestines may lead to disruption of the intestinal barrier and leakage of bacterial products into the circulation, which in turn may reduce the permeability of the blood-brain barrier and thus the brain may be affected,” said Tesfaye.
The researchers hope that their findings can be used to develop new treatments for IBS.
The study was published in the journal Genome Medicine.
Source: University of Bergen
