All participants underwent standardized clinical assessment, serological testing (IgA anti-tissue transglutaminase [tTG] and/or IgA anti-endomysial antibodies [EMAs]), upper digestive endoscopy with duodenal biopsies graded according to the Marsh-Oberhuber classification, and evaluation for <i>Helicobacter pylori</i> co-infection. This evidence concerns the gene TGM2 and coinfection.