To determine whether psoriasis is associated with the groups of alleles that are marked by specific amino acids within HLA proteins, we used the official protein sequences [31] assigned to each four-digit HLA allele to perform association testing at each amino acid position within HLA-A, -B, -C, -DQA1, -DQB1, and -DRB1. The gene discussed is HLA-DRB1; the disease is psoriasis.