Genetic Fingerprint May Lead to Better Diagnoses and Treatments
Researchers have developed the first genetic profile for Crohn's disease and ulcerative colitis, two types of inflammatory bowel diseases (IBD). The feat, reported in the March issue of Human Molecular Genetics, is a key step toward understanding and defining new treatments for IBD, which afflicts millions of Americans.
"Before this study, only a few genes involved in these diseases were known, but that list has been significantly expanded to 170 genes," says Shukti Chakravarti, Ph.D., an assistant professor of medicine at Johns Hopkins University School of Medicine. "Some of the identified genes may be involved in primary events, directly causing disease, whereas others are likely important in determining the course of disease. For instance, some of these genes play a role in the wounding and healing process, secondary events that lead to tissue damage and fibrosis."
In addition to paving the way for better therapies, Chakravarti, lead investigator of the study, says that the genetic "fingerprints" should also help physicians more specifically diagnose patients who remain in the vague category of having "some type of indeterminate bowel disease." The two diseases share many similar characteristics and thus are sometimes hard to differentiate, but they clearly have very different genetic profiles.
Applying DNA microarray technology, the most powerful method for gene expression profiling, Chakravarti analyzed colon tissue from six individuals who had Crohn's disease (CD), 12 with ulcerative colitis (UC), and six unaffected controls. The scientists screened 7,306 human genes, searching for ones that were activated or repressed in patients, and identified 29 genes uniquely altered in expression in Crohn's disease, 108 in ulcerative colitis, and 33 additional genes involved in both conditions.