The presence of enthesitis, which may be subclinical is very common in psoriasis and substantially increase the frequency of PsA in patients with psoriasis (Sakkas et al., 2019; Mease et al., 2019b) The pathogeneses of both PsA and psoriasis are incompletely understood, but innate and adaptive cells and proinflammatory cytokines are involved, particularly the interleukin(IL)-23/IL-17 axis (Sakkas and Bogdanos, 2017). The gene discussed is IL17A; the disease is psoriasis.