Leukemic transformation occurredin two patients (family 1:proband 1; duration:12 years; Family 1; proband’s young sister; duration 12 years), proband 1 harbouring EZH2 (c.707delC (p.Thr236fs mutation experienced erythropoietic failure (normoblasts:2%) with severe anemia. Here, EZH2 is linked to anemia.