FLG2 gene

The FLG2 gene (FLG2 stands for: Filaggrin 2) is a protein-coding gene located on chromosome 1q21.3. The FLG2 gene codes for the filaggrin-like protein. An important paralog of this gene is the HRNR gene (Hornerin gene).

The encoded filaggrin-like protein is involved in epithelial homeostasis. It is essential for normal cell-cell adhesion in the keratinized cell layers (Mohamad J et al. 2018) and thus for the proper integrity and mechanical strength of the stratum corneum of the epidermis.

The filaggrin-like protein is upregulated by calcium and proteolyzed by calpain 1.

Defects in this gene are associated with corneolytic skin diseases (see peeling skin syndrome below).

Furthermore, the encoded protein is important for the integrity of the skin barrier. In fact, C-terminal fragments of this protein show antimicrobial activity against P. aeruginosa and E. coli in addition to providing a physical barrier.

Diseases associated with FLG2 include:

• exfoliated skin syndrome 6 and
• exfoliated skin syndrome 3.

1. Bolling MC et al. (2018) Generalized Ichthyotic Peeling Skin Syndrome due to FLG2 Mutations. J Invest Dermatol 138:1881-1884.
2. Has C (2018) Peeling Skin Disorders: A Paradigm for Skin Desquamation. J Invest Dermatol 138:1689-1691.
3. Ishida-Yamamoto A et al. (2018) Clinical and molecular implications of structural changes to desmosomes and corneodesmosomes. J Dermatol 45:385-389.
4. Mohamad J et al. (2018) Filaggrin-2 deficiency leads to abnormal cell-cell adhesion in the keratinized cell layers and causes exfoliated skin syndrome type A. J Invest Dermatol 138:1736-1743.