DSG4 (Desmoglein 4) is a component of intercellular desmosome junctions. DSG4 is involved in the interaction of plaque proteins and intermediate filaments mediating cell-cell adhesion. DSG4 coordinates the transition from proliferation to differentiation in hair follicle keratinocytes. The essential role of desmoglein 4 in skin was established by identifying mutations in families with inherited hypotrichosis, as well as in the lanceolate hair mouse. The human desmoglein 4 (DSG4) demonstrates that it is composed of 16 exons spanning approximately 37 kb of 18q12 and is situated between DSG1 and DSG3. Defects in DSG4 are the cause of localized autosomal hypotrichosis (LAH). LAH is an autosomal recessive skin disorder. DSG4 is one of the target molecules recognized by autoantibodies in patients with pemphigus vulgaris. Pemphigus vulgaris is a potentially lethal skin disease in which epidermal blisters occur as the result of the loss of cell-cell adhesion.