Authors: Mohammed I, Cherkas LF, Riley SA, Spector TD, Trudgill NJ.

Institution: Department of Gastroenterology, Sandwell General Hospital, West Bromwich, United Kingdom.

Background: Aggregation of symptoms of abdominal pain or bowel disturbance has been described in the families of patients with irritable bowel syndrome (IBS). This may be due to environmental factors, including learned responses to abdominal symptoms or a genetic contribution to the etiology of IBS. OBJECTIVES: To determine the relative contribution of genetic factors to IBS by evaluating IBS symptoms in monozygotic (MZ) and dizygotic (DZ) twins.

Methods: A total of 4,480 unselected twin pairs identified from a national volunteer twin register were asked to complete a validated questionnaire. IBS was defined by the Rome II criteria.

Conclusion: Genetic factors are of little or no influence on IBS where the predominant influences appear to be environmental.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15929767&query_hl=64&itool=pubmed_docsum

• Genetic Influences in Irritable Bowel Syndrome: a Twin Study
• Irritable Bowel Syndrome in Twins: Heredity and Social Learning Both Contribute to Etiology
• The Natural History of Childhood Abdominal Pain and its Association with Adult Irritable Bowel Syndrome: Birth-Cohort Study
• Development of Irritable Bowel Syndrome may be Associated With a Parental History of Bowel Problems