A 5 aa insertion at the C-terminus of the C-terminal zinc finger of GATA1 as a result of an intronic splice variant affected two unrelated males with dyserythropoietic anemia, whereas for one patient with clinical bleeding, defective platelet aggregation in response to collagen, ADP, epinephrine, and arachidonic acid and severely impaired surface expression of the α-granule membrane marker P-selectin and the δ-granule/lysosome membrane marker CD63 in response to thrombin were shown [41]. The gene discussed is GATA1; the disease is Anemia of inadequate production.