Although the results of genome-wide association scans (GWAS) and high-density single-nucleotide polymorphism (SNP) data repeatedly point to HLA-C*06:02 as the most likely PSORS1 gene (Veal et al. 2002; Łuszczek et al. 2003; Nair et al. 2006; Feng et al. 2009; Capon 2017), the mechanism by which this allele predisposes to psoriasis is still poorly understood. The gene discussed is HLA-C; the disease is psoriasis.