The dyserythropoietic features detected in the bone marrow of II.4 supports the hypothesis that KCNN4 may play a role in erythroid maturation, suggested also by the I-V-curves in precursor cells indicating a higher abundance of Gardos channels in erythroid precursors compared to mature RBCs; therefore, iron overload detected in our and other patients with KCNN4 mutation11 may be a consequence of dyserythropoiesis, similar to what is reported in DHSt with PIEZO1 mutations28, 29. This evidence concerns the gene PIEZO1 and Tangier disease.