Because of the thinning or disappearance of the granular layer at psoriasis lesions, the spinous layer may prematurely express the products (such as fatty acid-binding protein, filaggrin, corneodesmosin, glutaminase, involucrin, and loricrin) normally expressed in the granular layer (Ruissen et al., 1996; Guttman-Yassky et al., 2009). This evidence concerns the gene CDSN and psoriasis.