Serologic and Genetic Markers Identify Celiac Disease in First-Degree Relatives of Patients

Dig Dis Sci 1999;44:2344-2349.

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Celiac.com 04/10/2000 - Dr. Carme Farre, of Hospital Sant Joan de Deu, in Barcelona, Spain, and his multi-center colleagues, report in the November issue of Digestive Diseases and Sciences that both serologic markers and the human lymphocyte antigen class II extended DQ2 (HLA-DQ2) haplotype are useful markers for screening first-degree relatives of patients with celiac disease for the disorder. These markers are more reliable predictors of celiac disease than other clinical features, which are absent from one third of relatives of people with celiac disease.

The researchers examined the usefulness of serologic markers, HLA-DQ2 haplotype, and clinical features common to celiac disease in the diagnosis of the disorder in 675 first-degree relatives of celiac disease patients. The diagnosis was confirmed by intestinal biopsy. Their results showed that 5.5% of the subjects were diagnosed with celiac disease, which is significantly higher than what was observed in the general public in a previous study. Serum IgA-class anti-endomysium antibodies (IgA-AEA) and IgA-class anti-gliadin antibodies (IgA-AGA) were observed in 5.8% and 1.9% of the relatives, respectively.

According to the researchers: Our results show that IgA-AEA is the most useful marker, since all but one IgA-AEA-positive relative showed histological findings of [celiac disease]. Further, the measurement of IgA-AGA would have missed 66% of the affected relatives. The researchers also concluded that the HLA-DQ2 haplotype also appeared to be a more useful indicator to determine which first-degree relatives had an increased genetic susceptibility to celiac disease, because the marker was detected in 93% of first-degree relatives found to have celiac disease, and 18% of those without it. The four most common clinical symptoms for celiac disease, diarrhea, anemia, food intolerance and growth retardation, were not found in one third of the relatives of patients with celiac disease.

The researchers conclude: Although the definitive diagnosis of [celiac disease] relies upon the intestinal biopsy, it should be preceded by a noninvasive, inexpensive and easy-to-perform screening technique. Their findings indicate that using blood serum IgA-AEA measurements is a useful screening tool for noninvasive screening, and HLA-DQ2 assessment may delineate a very high risk population with a particular genetic susceptibility to [celiac disease].