Filaggrin (FLG) - Differentiation marker for squamous epithelia

The FLG gene encodes the filaggrin protein which is an intermediate filament-associated protein found in skin and other keratinizing epithelia. The outermost layers of cells in the epidermis express filaggrin, a protein involved in aggregation of keratin filaments to maintain the skin barrier. Filaggrin is used as a marker for cornifying squamous epithelia. Fillagrin deficiency is linked to skin diseases such as ichthyosis vulgaris and eczema.