In psoriasis, skin lesions arise from complex processes involving maladaptive immune signalling among keratinocytes, dendritic cells, neutrophils and T-cells; implicated pathways include IL-17A, IL-22, IL-23 and TNF-α signalling (Albanesi et al., 2018; Koo et al., 2017). The gene discussed is TNF; the disease is psoriasis.