Desmoglein proteins are cadherin-type cell adhesion molecules. Desmoglein 4 (dsg4) shares 41% identity with human desmoglein 1, 37% with human desmoglein 2 and 50% with human desmoglein 3. A type I membrane protein of the cadherin protein family, dsg4 is expressed in salivary gland, suprabasal epidermis, hair follicle, testis, prostate and skin. In the hair follicle, dsg4 is an important mediator of keratinocyte cell adhesion and coordinates the transition from proliferation to differentiation. The human DSG4 gene is composed of 16 exons spanning approximately 37 kb of 18q12 and is situated between DSG1 and DSG3.