Psoriasis, as a disease of multifactorial involvement, is also implicated ininherited susceptibility alleles, TNF-α gene polymorphism in particular.TNF-α is generally considered as the master proinflammatory cytokine and isdeemed to be a key candidate gene for the pathogenesis of psoriasis, which canaccelerate the infiltration of lymphocytes, neutrophils and monocytes. The gene discussed is TNF; the disease is psoriasis.