Researchers at the University of Toronto have isolated a gene that predisposes people to Crohn's disease.
Crohn's disease is an inflammatory bowel disease and its prevalence is increasing in industrialized nations. Existing treatments are considered unsatisfactory, often requiring recurring hospitalization and surgeries. Using DNA samples from family groups, Siminovitch and her research team employed a technique called positional cloning to first locate the chromosome containing the gene and then identify the gene.
The gene isolated by the researchers produces a protein that sits on the cell surface 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.
The ability to test for this protein malfunction will help physicians distinguish between Crohn's disease and ulcerative colitis, the other major form of inflammatory bowel disease known. The malfunction is not present in ulcerative colitis, so this gene alteration provides a diagnostic test to help distinguish between the two diseases. Siminovitch says that this information can also be used to diagnose Crohn's disease at an earlier stage and to develop new approaches to treatment. She and her fellow researchers are now working on the development of a chemical that would alter the protein to restore its normal function.