C2 and psoriasis: Genes with strong signals in both GWAS (p < 5e-8) and EWAS (p < 1e-5) were mostly peripheral nodes in the networks (Fig. 3), such as C2, FYN, ICAM3, LTB, PSMB8, TAP1, and TNF. Exclusion of HLA genes from the nine psoriasis-associated supersets did not appear to have major influence on the KDs identified (Additional file 1: Table S9).