As both PV and PF are prevalent in southeastern Brazil, there is an opportunity for outpatient follow-up of a large series of patients.4, 5 In the PF series, over a 25-year period, it was observed that 6,64 % of the patients, in addition to being positive for anti-Dsg1, also had reactive titers to Dsg3 in the ELISA test, without, however, showing a phenotype of mucosal lesions. The gene discussed is DSG1; the disease is acquired polycythemia vera.