A Single Nucleotide Polymorphism Of MHC Region

Background Psoriasis is a common inflammatory cutaneous disorder characterized by red scaly patches. The prevalevence of psoriasis is about 0.123% in Chinese Han population. So far there have heen about 4 million psoriasis patients in China.Clinically, psoriasis vulgaris is the most common, accounting for the total number of patients over 90%. The exact pathogenesis of psoriasis remains unclear. It is agreed generally that the psoriasis is a complex disease which arises from genetic and environmental factors. The predisposing genes can be grouped into two parts: HLA-associated and lacking HLA associations genes. Genome wide association study is a kind of genome-wide within the common genetic variation (single nucleotide polymorphisms and copy number variation) for the overall correlation analysis method, the comprehensive study of the disease within the whole genome can be a one-time overview of outline for complex diseases research,including Psoriasis.Whether association analysis or the present whole-genome association analysis ,are prompted to demolish the pain of human autoimmune diseases involving the immune response of MHC loci (eg HLA-Cw6, and other MHC variants) are closely related.Objective The purpose of this study was to confirm the association of a Single Nucleotide Polymorphisms (SNP) within MHC locus with psoriasis and to investigate the relationship between this SNP and subphenotypes of psoriasis in Chinese. Methods After genotyping rs1265181 in 2519 cases and 2498 controls and combining with the prior study samples (1139 cases and 1132 controls), we set up a model to classify all patients into Risk Allele Group (RAG) and Protective Allele Group (PAG). According to this, we investigate the distribution of subphenotypes of psoriasis in different groups.Results Extremely high significance of association was detected between rs1265181 and psoriasis in combined result and was under the dominant model (P <10-300, OR =23.4, 95%CI: 20.7-26.4). We observed that 82.06% of samples with risk allele (G) of this SNP were psoriasis patients and 83.63% of samples taking protective (C) alleles were controls. RAG patients (n=3079) had an earlier disease onset, higher incidence of severe disease, higher frequency of guttate psoriasis, more affected in trunk and more susceptible to diabetes mellitus. PAG patients (n=579) had more scalp involvement. However, there was no statistically significant difference between the two groups regarding age and gender.