In conclusion, our study presents new insights in how GATA1 missense variants C-terminally located to the second zinc finger domain can affect platelet phenotype and function and erythropoiesis in hemizygous and heterozygous carriers and that a heterozygous SLC4A1 c.2210C>T p.A737V variant compounds mild dyserythropoiesis to mild spherocytosis and hemolysis. The gene discussed is SLC4A1; the disease is hereditary spherocytosis.