HLA-DQ2 is the predominant molecule in CD (over 90% of CD patients) It is now well accepted that the major gluten protein involved in CD is the α-gliadin isoform having the main 33-mer immunogenic fragment comprising six overlapping DQ2-restricted toxic epitopes (blocks of PFPPQQ and PYPQPQ) and an additional DQ2-restricted epitope which partially overlaps with the 33-mer peptide (4, 30, 37) (Figure 5). This evidence concerns the gene TOR1A and Cowden disease.