It was originally thought that the clinical phenotype of pemphigus is defined by the anti-Dsg autoantibody profile as follows: anti-Dsg 1 antibody alone is associated with PF, anti-Dsg 3 antibody alone—with mucosal variant of PV, and both antibodies—with mucocutaneous variant of PV [115]. This evidence concerns the gene DSG1 and acquired polycythemia vera.