First Crohn's Disease Gene Identified

N E W   Y O R K, May 21 -- Researchers say they have identified the first genetic abnormality associated with Crohn's disease, a finding that should help doctors better understand the devastating gastrointestinal disorder and lead to new drugs to treat it.

Crohn's disease is a serious inflammation of the gastrointestinal tract, causing diarrhea, crampy abdominal pain, fever, and at times rectal bleeding. Loss of appetite, weight loss and hospitalizations can also occur.

The disease, which currently affects about 500,000 Americans, is chronic. Most cases are diagnosed before age 30, but the disease can also be seen in the elderly. Episodes recur even after patients take medication, which usually tries to control the symptoms of inflammation.

The number of new cases has been increasing, reflecting changes in the environment and lifestyle, scientists say. The disease tends to cluster in families suggesting that genes play an important role.

Researchers believe faulty responses in Crohn's patients to microbes that live in the stomach may somehow trigger the immune system to attack the intestinal lining, causing it to ulcerate and break up.

Gene on Chromosome 16

Many genes are believed to be responsible for Crohn's disease. In 1996, researchers first reported that a susceptibility to the disorder mapped to a location on human chromosome 16.

Today researchers, from two groups, one European and the other American, are reporting they identified a specific gene, called Nod-2 on chromosome 16 that seems to be associated with the disease in approximately 15 percent to 20 percent of Crohn's patients.

The findings are published in two articles in the May 31 issue of the scientific journal Nature. The results are being reported early at a meeting today of the Digestive Disease Week Conference in Atlanta.

"Finding this crucial genetic clue gives us our first real insight into the complex causes of Crohn's disease,' says American study co-author Dr. Judith Cho, assistant professor of medicine and a researcher in the Martin Boyer Laboratories at the University of Chicago.