The combination of HbE with IVSI (G->C) is quite common, but the outcome is unpredictable, as it usually is with HbE beta thal. The PSU database lists this combination as having a typical hemoglobin level of 7, which is the borderline for when transfusions are always recommended. This is similar to thal intermedia and transfusions are determined by need. Folic acid is specifically recommended.