Following the positive result for IgG antibodies BP 180 (74.1 RU/mL; n.v. < 20 RU/mL) and anti-Dsg3 IgG autoantibodies (105.6 RU/mL; n.v. < 20 RU/mlL) and negative result for anti-Dsg1 IgG autoantibodies and anti-epithelium antibodies (1:40), the diagnosis of PV was made (Table 1). This evidence concerns the gene DSG1 and acquired polycythemia vera.