A single nucleotide polymorphism -35 kb T>C (rs9264942) is strongly associated with psoriasis vulgaris depending on HLA-Cw(∗)06.

HLA class I molecules play a role both in viral infection control and in autoimmune diseases development. rs9264942T>C polymorphism in HLA-C gene was found to impact on HLA-C surface expression level and to be associated with HIV-1 control. It was found that these HLA alleles which protect against AIDS are associated with autoimmune disease e.g. psoriasis vulgaris (PsV). Whether rs9264942 SNP is associated with PsV was investigated here. rs9264942T>C was genotyped in 292 PsV patients, and 254 controls using TaqMan Genotyping Assay. PsV patients differed from controls in frequencies of rs9264942T>C alleles (p=3.62 × 10(-16)) and genotypes (5.67 × 10(-15)). However, rs9264942C allele was predisposing to PsV 3-fold weaker than HLA-Cw(∗)06 (OR=5.04 vs. OR=15.61, respectively). In addition, this SNP was described earlier to be in strong linkage disequilibrium (LD) with another SNP, rs67384697 ins/del, which by affecting a microRNA binding is responsible for regulating HLA-C expression. However, typing for is cheaper and simpler than that for rs67384697, therefore we think it may substitute for it to some extent.