Crohn's disease, which shares some pathophysiological features with psoriasis [34] and is also slightly enriched for HLA-C*06:02 (p = 4.2×10−5, OR 1.32) and HLA-B*57:01 (p = 3.68×10−4, OR 1.40), showed some similarity to psoriasis and HIV-1 control at these positions, but the magnitude of the association was smaller and several important residues such as Asn70 and Asn97 in HLA-B and Gln156 in HLA-C were not concordant. This evidence concerns the gene HLA-C and Crohn disease.