A gene that puts people at risk of Crohn's disease has been identified by researchers.
Scans currently pick up bowel disorders
The University of Toronto scientists say the discovery will lead to better diagnosis and treatment of the inflammatory bowel condition.
The gene produces a protein that functions improperly in patients with the disease.
Doctors said several genes had been linked to the disease though the latest breakthrough could prove helpful.
Crohn's disease is an inflammatory bowel disease which is increasing in industrialised countries.
Current treatments often require hospitalisation and surgery.
The researchers used DNA samples from family groups to locate the gene.
It produces a protein which sits on the surface of cells and regulates how substances enter and exit the cell.
In a majority of Crohn's disease patients, this protein functions improperly and allows toxins easier access to the cell.
Testing for this protein malfunction would allow doctors to distinguish between Crohn's disease and ulcerative colitis, in which it does not occur.
The researchers, who say the gene is not the only one involved in the disease, are now working on a chemical which could repair the protein.
Professor Katherine Siminovitch at the university said: "Isolating this gene is a critical step towards improved diagnosis of this disease and developing better therapies for Crohn's sufferers.
"There's an urgent need for better treatment for patients with Crohn's."
She added: "If we can identify the majority of the genes involved in this disease, we can learn how these genes act together to cause disease. This information will help us identify potentially preventable environmental triggers as well."
Dr Peter Hawker, a consultant gastroenterologist at Warwick Hospital, said there were a number of factors, including a genetic component, which dictated whether a person would develop Crohn's disease.
"There are some patients where it is difficult to make a diagnosis, you can't place them into the Crohn's category but you know there is something wrong with their gut," he said.
"A genetic test could show it is more likely it is Crohn's disease and may effect management of the patient."
However Dr Hawker said he had yet to see genetic discoveries leading to new treatments in practise and one study alone, though useful, was unlikely to have a big impact.
Richard Driscoll, director of the National Association for Colitis and Crohn's Disease, said particular genes had a role in specific subsets of the disease.