Among several models developed for both dermatitis and ankylosing enthesitis (Mandour et al, 2021), we selected male DBA/1J mice caged together, in which the symptoms were dependent on IL-17A (Ebihara et al, 2015) and human PsA (McInnes et al, 2015; Mease et al, 2017). The gene discussed is IL17A; the disease is skin disorder.