In people with psoriasis who subsequently develop axSpA, or in people with predominant skin involvement where targeted therapies have been led by dermatologists, decisions to switch therapy should consider that certain therapies used in psoriasis have no beneficial effect for axial symptoms (e.g. ustekinumab or IL-23p19 inhibitors), while other inhibitors of IL-17 signalling have (e.g. brodalumab [78]) or are likely to have therapeutic benefit despite not being licenced for axSpA. The gene discussed is IL23A; the disease is psoriasis.