An 80‐year‐old man, diagnosed with a JAK2 V617F mutation positive‐polycythemia vera (PV) (Figure 1A–C) with a diploid karyotype in 2011, treated with hydroxyurea and phlebotomies, presented in 2021 with increasing fatigue and unintentional weight loss. The gene discussed is JAK2; the disease is acquired polycythemia vera.