Filaggrin Mutations Associated with Skin and Allergic Diseases

Mutations in the filaggrin gene are associated with a broad range of skin and allergic diseases. The biology of this molecule and the role of mutations in its altered function offer new insights into a range of conditions not previously thought to be related to one another. Mutations in the filaggrin gene ( FLG ) are among the most common and profound single-gene defects identified to date in the causation and modification of disease. FLG encodes an important epidermal protein abundantly expressed in the outer layers of the epidermis. 1 Approximately 10% of persons of European ancestry are heterozygous carriers of a loss-of-function mutation in FLG, resulting in a 50% reduction in expressed protein. 2 The critical role of filaggrin in epidermal function underlies the pathogenic importance of this gene in common dermatologic and allergic diseases. The spectrum of such diseases encompasses monogenic disorders of keratinization through complex abnormalities . . .