Many people with irritable bowel syndrome are the only known people with IBS in their families, while others report relatives, sometimes many, who also have or had a diagnosis or symptoms suggestive of IBS and/or one or more of several other chronic conditions that commonly overlap with IBS. This suggests that there are genetic influences in the development of IBS for at least some affected people. Narrowing down precisely what they are has been one of many diverse areas of IBS research in recent years.
A few weeks ago, a team led by principal investigator Miranda van Tilburg, PhD, Associate Professor of Medicine at the University of North Carolina Center for Functional GI and Motility Disorders, published results that show that a small percentage of cases appear, at least in part, to be linked to dysfunction in mitochondrial DNA. Mitochondria are subunits within cells that are involved in generating cellular energy. In human beings, mitochondria are inherited only through a person’s biological mother. Previous medical research has shown that problems with mitochondria also appear to be involved in other functional gastrointestinal disorders, chronic fatigue syndrome, depression and migraines, all of which are commonly overlapping conditions with IBS.
Dr. van Tilburg and her colleagues studied Caucasian adults who included 308 known to have irritable bowel syndrome (IBS), 102 healthy controls and 36 known to have inflammatory bowel disease (IBD). The researchers found probable maternal inheritance in 17.5% of study volunteers with IBS, in contrast to 2% in the control group and 0% of those in the IBD group. The researchers called this a “significant minority” who may have a form of IBS inherited through mitochondrial DNA. Dr. van Tilburg and her colleagues emphasized that the sample size was small, and the results should be replicated with larger groups and further research. There is no single IBS gene per se, that is known at this time.
These are intriguing results that appear to be promising in understanding possible causes of irritable bowel syndrome and, along with other recent genetic and biomarker research as discussed on this blog on February 9, 2014, perhaps collectively leading to usable diagnostic tests and improved treatment options in the long-term future. IBS Impact commends this important scientific work, and looks forward to further progress and answers for our community in the years ahead.