When the study began, it was well known that individuals with celiac disease have specific tissue types that identify wheat proteins. Why healthy individuals with the same tissue type failed to develop celiac symptoms or celiac disease remained unknown, and was a key question the team set out to answer. The team was led David van Heel, Professor of Gastrointestinal Genetics at Queen Mary, University of London. The Human Genome Project and the Hap Map Project played key support roles in the study.
The results show that a protective DNA sequence in a specific gene segment, generally found in healthy individuals are missing in people with celiac disease. The research team evaluated genome data of 778 individuals with celiac disease and 1,422 controls non-celiacs within the British, Irish and Dutch populations.
Researchers discovered that, compared to people with celiac disease, healthy people more commonly have a DNA sequence in the interleukin-2 and interleukin-21 gene region that protects against celiac disease. Interleukin-2 and interleukin-21 are cytokine proteins that are secreted by white blood cells, and which control inflammation. In people with celiac disease, the protective DNA sequence most likely leads to lesser amounts of these cytokines being produced, which weakens the defense against intestinal inflammation.
About 1 in 133 people develop the disease, but, so far, predicting those at risk to develop the disease has been haphazard at best. Present methods of genetic testing can only narrow down the search to about 30% of the general population. These results give doctors a means to discover what further genetic risk factors leave people vulnerable to developing celiac disease.
Queen Mary, University of London Press Release - Public release date: 10-Jun-2007health writer who lives in San Francisco and is a frequent author of articles for Celiac.com.