3→HbH disease(β4) moderate to severe microcytic hypochromic anemia
4→Hb Barts disease(γ4) hydrops fetalis(incompatible with life)
☆anasarca全身浮腫, ascites, pleural/pericardial effusions
→has to have both parents with more severe form of alpha thalassemia than alpha thalassemia minor(not minima)