Haplotype analysis suggests that the coexistence of the polymorphisms rs1799964 (TNF-α), rs2010963 (VEGF), rs833061 (VEGF), and rs6311 (5HT2A) may be a protective factor for psoriasis.
After correction for multiple testing with a false discovery rate of 5%, two SNPs remained significant: TNF (rs361525) was associated with PsO, PsC10, and PsA; and IL12B (rs6887695) was associated with PsO.
By contrast, healthy individuals homozygous for the common variant D10N, located in the ACT1 tumor necrosis factor receptor-associated factor-interacting domain and previously associated with psoriasis, had impaired, but not abolished, responses to IL-17 cytokines.