Figure 2.

Downregulation of filaggrin in skin diseases and experimental conditions related to epidermal barrier dysfunction. Loss-of-function mutations of FLG (encoding filaggrin) are associated with skin disorders related to barrier dysfunction, including atopic dermatitis (AD) and ichthyoses. Expression levels of filaggrin have also been reported to be reduced in experimental conditions of the disrupted epidermal barrier by tape stripping or retinoic acid (RA) application. SASPase (skin aspartic protease) generates filaggrin monomers from profilaggrin. Loss-of-function mutations of SASPase are associated with ichthyosis in dogs.