Ten to twelve filaggrin units are post-translationally hydrolyzed from a large profilaggrin precursor protein during terminal differentiation of epidermal cells.

[3] In humans, profilaggrin is encoded by the FLG gene, which is part of the S100 fused-type protein (SFTP) family within the epidermal differentiation complex on chromosome 1q21.

Filaggrin undergoes further processing in the upper stratum corneum to release free amino acids that assist in water retention.

[9] Individuals with truncation mutations in the gene coding for filaggrin are strongly predisposed to a severe form of dry skin, ichthyosis vulgaris, and/or eczema.

[13] The barrier defect seen in filaggrin null carriers also appears to lead to increased asthma susceptibility and exacerbations.