Chronic
blood transfusions start at a very young age in subjects with transfusion-dependent
anemias, the majority of whom have hereditary
anemias. To understand how rapidly
iron overload develops, we retrospectively reviewed 308 MRIs for evaluation of liver, pancreatic, or cardiac
iron in 125 subjects less than 10 years old. Median age at first MRI evaluation was 6.0 years. Median liver
iron concentrations in patients less than 3.5 years old were 14 and 13 mg/g dry weight in
thalassemia major (TM) and
Diamond-Blackfan anemia (DBA) patients, respectively. At time of first MRI, pancreatic
iron was markedly elevated (> 100 Hz) in DBA patients, and cardiac
iron ( R₂* >50 Hz) was present in 5/112 subjects (4.5%), including a 2.5 years old subject with DBA. Five of 14 patients (38%) with
congenital dyserythropoietic anemia (CDA) developed excess cardiac
iron before their 10th birthday. Thus, clinically significant hepatic and cardiac
iron accumulation occurs at an early age in patients on chronic transfusions, particularly in those with ineffective or absent erythropoiesis, such as DBA, CDA, and TM, who are at higher risk for
iron cardiomyopathy. Performing MRI for
iron evaluation in the liver, heart, and pancreas as early as feasible, particularly in those conditions in which there is suppressed bone marrow activity is very important in the management of
iron loaded children in order to prescribe appropriate chelation to prevent long-term sequelae.