According to reports collected in Argentina, Brazil, Colombia, Uruguay, Chile, Bolivia, Peru, Costa Rica, Puerto Rico, and Ecuador, the combined PV prevalence has been estimated to be between 43 and 54% for MLH1; 32.4 to 43% for MSH2; 9 to 10% for MSH6%; 3 to 10% for PMS2, and nearly 1% for EPCAM [13,15,16]. The gene discussed is MLH1; the disease is acquired polycythemia vera.