Third Genetic Marker for Celiac Disease Discovered

August 11, 2009

A third Class II HLA gene has been identified as another risk factor for celiac disease by a researcher at the University of the Basque Country in Spain.

A third Class II HLA gene has been identified as another risk factor for celiac disease by a researcher at the University of the Basque Country in Spain.

Itziar Zubillaga Azpiroz, who is working on her PhD, found that the HLA-DRB1 gene, in addition to the HLA-DQA1 and HLA-DQB1 genes, “confers a genetic susceptibility to contracting the disorder.” The two previously known genes, HLA-DQA1 and HLA-DQB1, were shown to indicate 40% of the “genetic tendency” to contract celiac disease. Now, with HLA-DRB1 as an additional genetic risk factor for celiac disease, researchers showed “a positive predictive value of 100% and a negative predictive value of 97%” for predicting genetic risk for the disease.

Azpiroz examined the cases of 175 patients afflicted with celiac disease. Analysis of the Class II HLA genes showed that a “genetic imbalance” existed in the patients. Study results showed that “90-95% of patients with celiac disease have illness-related HLA genes,” and “90% of these are carriers of the HLA-DQ2 molecule.”

In terms of diagnosing celiac disease, Azpiroz has shown that patients who are carriers of two of the gens have the greatest risk for contracting the illness, while “carriers of a single copy of the HLA-DQ2 and HLA-DQ8 molecules are at medium risk,” and then there are patients who are “carriers of at least one of HLA genes that code for the HLA-DQ2 molecule.” These individuals were at the lowest risk for contracting celiac disease among all the patients studied, thoughceliac-disease.jpg they were still at a higher risk than patients who did not carry any of the Class II HLA genes.

According to the research, “all those patients in which celiac disease was suspected and who showed both serological and genetic markers fixed for the diagnosis of the disease in these analyses proved in the end to be celiac sufferers,” so results of the new research may provide a new method for testing for the disease.