In humans, selective IL-23 blockade has demonstrated clinical benefit in psoriasis and psoriatic arthritis (Blauvelt et al, 2020, 2017; Coates et al, 2022; Deodhar et al, 2020; Gordon et al, 2018; Mease et al, 2020; Papp et al, 2017; Reich et al, 2017a, 2017b; Wolk et al, 2006; Zaba et al, 2007). The gene discussed is IL23A; the disease is psoriasis.