HLA-C and psoriasis: In particular, the IBD3 locus involved in CD and UC, and the PSORS1 locus involved in psoriasis, were found in the 6P21 region [36], and the gene encoding the interleukin 23 receptor (IL-23R) and interleukin 12B (IL-12B) are both implicated in the pathogenesis of psoriasis and IBD [37].