C1orf141 is a genetic locus located on chromosome 1 that functions as a susceptibility gene for multiple inflammatory diseases. Positioned adjacent to IL23R, the C1orf141-IL23R locus represents a major genetic risk factor for several conditions. In sarcoidosis, this locus shows the largest effect size among identified susceptibility loci 1, with disease-risk alleles associated with reduced IL23R expression 2. The locus is strongly associated with Vogt-Koyanagi-Harada (VKH) disease, a systemic inflammatory disorder affecting pigmented tissues including the eye, with multiple SNPs (rs78377598, rs117633859) showing significant associations across populations 34. The risk allele in the IL23R promoter region exhibits diminished transcriptional activation and reduced IL23R mRNA expression 4. C1orf141 variants are also implicated in uveitis susceptibility more broadly 5 and psoriasis 6. The shared genetic pathway involves IL23R-mediated immune regulation, suggesting that C1orf141-IL23R dysfunction compromises host defense and promotes aberrant T cell activation and cytokine production 1. These associations are evident across multiple ethnic populations, establishing C1orf141 as a clinically relevant genetic risk factor for inflammatory and autoimmune diseases.