Five of these fifteen newly identified non-HLA genes were shown to be significantly enriched in the network (MTHFR, NPPA, AIM2, CASR and IFNGR2; FDR <0.1) (Supplementary Fig. 8).Gene expression analysis on the basis of public psoriasis databases38 indicated that most of the susceptibility genes, newly identified or confirmed in this study, display highly differential expression in skin from psoriatic patients compared with normal controls (Supplementary Table 7). Here, NPPA is linked to psoriasis.