DSG4
DSG4, or desmoglein-4, is the desmosomal cadherin most closely tied to hair follicle biology, with expression concentrated in the inner root sheath, hair matrix, and differentiating keratinocytes. Like other desmogleins it contributes calcium-dependent adhesion to desmosomes, but its loss is selectively manifest in hair shaft formation. Recessive mutations in DSG4 cause localized autosomal recessive hypotrichosis and the monilethrix-like fragile-hair phenotype, and Dsg4-deficient mice show hair shaft defects with follicular cyst formation. The restricted phenotype, in contrast to the widespread epithelial blistering caused by DSG1 or DSG3 disruption, underscores the tissue-specific division of labor within the desmoglein subfamily.
