PSORS1C1 (psoriasis susceptibility 1 candidate 1) is a candidate gene located 127 kb telomeric to the HLA-C locus on chromosome 6 involved in autoimmune disease susceptibility 1. The gene encodes a protein whose expression is upregulated in disease states, with elevated levels detected in blood of rheumatoid arthritis (RA) patients and increased expression in RA synovial tissues 2. Functionally, PSORS1C1 knockdown in rheumatoid synovial fibroblasts decreases IL-17 and IL-1β production, suggesting involvement in inflammatory cytokine regulation 2. Genetically, specific SNPs in PSORS1C1 (rs1062470, rs3130983, rs4959053) demonstrate associations with psoriasis risk, with stronger effects in early-onset disease and male-specific associations with disease severity 3. The gene also associates with systemic sclerosis (P = 5.70×10⁻¹⁰) 4, Graves' disease susceptibility 5, and shares genetic architecture with depression and obesity comorbidity through immunometabolic pathways 6. However, in Chinese populations, PSORS1C1 polymorphisms showed no significant association with chr6 plaque psoriasis after correction for multiple testing 1. PSORS1C1 represents a pleiotropic autoimmunity risk locus with potential as a therapeutic target for multiple immune-mediated diseases.