Is IBS Genetic?

The results of recent studies at the Institute of Human Genetics do indicate that irritable bowel syndrome can have genetic causes. Mutations in certain genes have been frequently seen in IBS patients who are most prone to diarrhea rather than constipation as a symptom. Changes in the number of surface cell receptors or in the composition of the genes are caused by these mutations. As a result, signals that are controlled by the transfer of genetic material are disturbed, leading to excessive stimulation of the intestine. This affects the normal balance of fluid in the intestinal tract and results in diarrhea.

Additionally, a direct link between pain, depression and IBS has been established in patients with these genetic mutations, indicating further that these mutations can cause IBS. Although new studies have identified genetic abnormalities that occur commonly in IBS patients, further research is necessary before it can be determined whether or not a specific gene that causes IBS may exist or if mutations of genes are a root cause of the disorder. Currently, research is being done on the genetic structure of this disorder. The purpose of this research is to help identify and explain the co-existence of other disorders such as pain, depression and anxiety with IBS. Additionally, it will be possible to use these genetic discoveries to identify groups of patients who will respond to treatment of the disorder that has been customized to fit their genetic profile. Because of the multiple symptoms presented in patients with IBS, it is difficult to replicate the results of genetic abnormalities, meaning conclusions about the role of genetics in the disease will need to be handled with caution.

A different type of genetic affectation is that of genes passed down from parents to their children. In a survey of 117 pairs of identical twins and 164 pairs of fraternal twins with irritable bowel syndrome in the state of Virginia confirmed that each pair suffered from the disorder. Additionally, 17% of the mothers of identical twins were diagnosed with IBS and 15% of the mothers of fraternal twins were diagnosed with the disorder. Identical twins will share the same number of gene sets with each other. Fraternal twins will have the same number of gene sets with each other as their mothers have with them. The rate of occurrence of IBS in twin sets does indicate that there is a clear genetic connection and that the disorder can be passed down from parent to child.