An asparagine residue at position 97 of HLA-B is predominantly found on HLA-B*27 alleles, and HLA-B*27:05 is the most associated HLA allele after correcting for age of psoriasis onset (p=3.53×10−7, OR 2.34, 95% CI 1.69 to 3.25); in addition, a serine residue is found on multiple HLA alleles including HLA-B*07 (p=1.9×10−3) and HLA-B*08 (p=0.05). The gene discussed is HLA-B; the disease is psoriasis.