An international team of scientists believe they have identified a number of genes that may indicate a pre-disposal to developing Crohn's disease and say their discovery confirms the suspicion that the inflammatory bowel ailment has a strong genetic link.
As a rule Crohn's disease is diagnosed in people between the ages of 20 and 30; the debilitating condition usually affects the small intestine and can cause abdominal pain, diarrhea, rectal bleeding, weight loss and arthritis.
The researchers trawled through the entire genome of approximately 1,000 Crohn's patients and 1,000 healthy controls and tested more than 300,000 genetic variations.
Their findings were then tested in two additional sets of patients and controls and lead researcher John Rioux PhD now at the Universite de Montreal, says previous studies had identified two genes involved in the disease but they have now identified eight or nine genes.
According to the researchers their findings demonstrate that genetics play a crucial role in the disease but environmental factors also are involved; smoking appears to increase the risk.
The researchers believe that being able to pinpoint the genes that predispose people to Crohn's disease could lead to new ways to treat the disease.
A genetic component to Crohn's disease was indicated from a previous study by co-senior author Dr. Mark Daly of the MGH Center for Human Genetics Research and the Broad Institute and Dr.Rioux, where they found it appeared to run in families and was more common in certain ethnic groups, especially people of central and eastern European Jewish descent.
Experts suspect a fault exists in the response to the microbes that live in the human digestive system which in some way causes the immune system to attack the lining of the digestive tract, making it decay and become inflamed.
Rioux says some of the genes identified as risk factors are involved in the body's ability to deal with microbes.
Crohn's disease is named after Dr. Burrill Crohn who discovered it in 1932; it can affect any area from the mouth to the anus but most often affects the lower part of the small intestine, known as the ileum and is also called ileitis or enteritis.