In patients with clonal HE (with or without HES), several different molecular markers can be detected, such as fusion genes involving PDGFRA (eg FIP1L1‐PDGFRA), PDGFRB, FGFR1, ABL1 or JAK2 (eg PCM1‐JAK2).83 The gene discussed is PDGFRA; the disease is hypereosinophilic syndrome.