PSO is characterized by atrophy and sometimes absence of SGs in the affected skin samples, raising the questions of whether this plays a role in the development and progression of the disease and whether the alterations in the expression of lipid metabolism-related genes (AWAT2, DHCR7, ELOVL5 or FAR2) identified in this study are specific to PSO. This evidence concerns the gene FAR2 and Atrophy.