Acantholysis: Separation of the prickle cells of the stratum spinosum of the epidermis, resulting in atrophy of the prickle cell layer. It is seen in diseases such as pemphigus vulgaris (see PEMPHIGUS) and DARIER DISEASE.Pemphigus: Group of chronic blistering diseases characterized histologically by ACANTHOLYSIS and blister formation within the EPIDERMIS.Desmoglein 3: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS VULGARIS.Desmoglein 1: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS FOLIACEUS.Desmosomes: A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Darier Disease: An autosomal dominantly inherited skin disorder characterized by warty malodorous papules that coalesce into plaques. It is caused by mutations in the ATP2A2 gene encoding SERCA2 protein, one of the SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. The condition is similar, clinically and histologically, to BENIGN FAMILIAL PEMPHIGUS, another autosomal dominant skin disorder. Both diseases have defective calcium pumps (CALCIUM-TRANSPORTING ATPASES) and unstable desmosomal adhesion junctions (DESMOSOMES) between KERATINOCYTES.Pemphigus, Benign Familial: An autosomal dominantly inherited skin disorder characterized by recurrent eruptions of vesicles and BULLAE mainly on the neck, axillae, and groin. Mutations in the ATP2C1 gene (encoding the secretory pathway Ca2++/Mn2++ ATPase 1 (SPCA1)) cause this disease. It is clinically and histologically similar to DARIER DISEASE - both have abnormal, unstable DESMOSOMES between KERATINOCYTES and defective CALCIUM-TRANSPORTING ATPASES. It is unrelated to PEMPHIGUS VULGARIS though it closely resembles that disease.Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.Blister: Visible accumulations of fluid within or beneath the epidermis.Desmogleins: A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical CADHERINS.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.