An international team of researchers has identified 21 new genetic risk factors for Crohn's disease, bringing the total number of genes linked with the disease to 32. The findings may one day help researchers to develop new treatments for the disease.

Crohn's disease affects close to half a million people across Europe, and many more around the world. This chronic inflammatory bowel disease has, as yet, no cure and its exact cause is still unknown. Its symptoms include abdominal pain, diarrhoea, constipation, vomiting, weight loss or weight gain.

The condition is widely believed by the medical community to be an autoimmune disease and genetically linked, although smokers are more likely to get Crohn's disease than non-smokers.

'We now know of more than 30 genetic regions that affect susceptibility to Crohn's disease,' commented Dr Jeffrey Barrett from the Wellcome Trust Centre for Human Genetics at the University of Oxford, lead author of the study.

'These explain only about a fifth of the genetic risk, which implies that there may be hundreds of genes implicated in the disease, each increasing susceptibility by a small amount,' he continued.

The international consortium was made up of three separate research teams, with one based in North America, involving six institutions and clinical sites; a UK team supported by the Wellcome Trust; and a group of French and Belgian investigators. The results of their research can be read in the journal Nature Genetics.

The three teams were able to combine their data through a process called meta-analysis, allowing the comparison of data from more than 3,200 Crohn's patients with more than 4,800 controls. This was supplemented by an analysis of new data from an additional 3,700 patients and matching controls.

Their discovery reveals the genetics behind the disease and greatly assists researchers in producing new therapies which may help sufferers.

'This greatly increases our knowledge of the genetic architecture of Crohn's and gives us more detailed insight into the biological underpinnings of the disease,' says Mark Daly, of the Massachusetts General Hospital (MGH) Center for Human Genetic Research and the Broad Institute of MIT and Harvard. 'Better understanding of the precise functions of these genes and the molecular effects of Crohn's-associated variants should lead us to novel strategies for therapies and, someday, prevention.'

Nature Genetics

Source: Community R&D Information Service (CORDIS)