 Participants will be randomized to 1 year of treatment with L1DFO combination therapy or DFO monotherapy. At baseline, 6 months, and 1 year on therapy, cardiac function will be assessed by MRI measurement of left ventricular ejection fraction LVEF, T2, Holter monitoring, and electrocardiography. Additional monitoring for safety includes weekly blood testing, monthly visits, and periodic eye and ear exams. 