Filaggrinis an intermediate filament-associated protein that aggregates keratin intermediate filaments in mammalian epidermis. It is initially synthesized as a polyprotein precursor, profilaggrin (consisting of multiple filaggrin units of 324 aa each), which is localized in keratohyalin granules, and is subsequently proteolytically processed into individual functional filaggrin molecules. Mutations in this gene are associated with ichthyosis vulgaris. This structure is similar to that of the mouse; however, the human filaggrin repeat is much longer (972 basepairs; 324 amino acids) and shows little sequence homology to the mouse protein. Amino acid sequences encoding the amino and carboxyl termini were more conserved, as were the 5-prime and 3-prime DNA sequences flanking the coding portions of the gene.