When analysing the functional profile of these, we observed that cluster III, containing genes upregulated in PPARβ/δ mice but downregulated in psoriasis, was enriched for markers of late epidermal differentiation (e.g. FLG, PCDH21), indicative of cells in the so-called granular layer, which is prominent in PPARβ/δ mice (fig. This evidence concerns the gene PPARD and psoriasis.