Relevant for CD, the occurrence and frequency of the HLA-DQ2 epitopes DQ2-Glia-α1, DQ2-Glia-α2 and DQ2-Glia-α3 (previously designated Glia-α20, ref. 12] and the HLA-DQ8 T-cell epitope DQ8-Glia-α1 also differs between the loci [17]. This evidence concerns the gene TOR1A and Cowden disease.