In severe or refractory psoriasis, guidelines recommend using biological therapies directed against TNF-alpha (adalimumab, etanercept, certolizumab, infliximab) or the IL-23/17 axis (ustekinumab, guselkumab, risankizumab, tildrakizumab, brodalumab, ixekizumab, secukinumab, bimekizumab) [18,19]. This evidence concerns the gene IL23A and psoriasis.