Diabetes mellitus caused by secondary hemochromatosis after multiple blood transfusions in 2 patients with severe aplastic anemia

Hemochromatosis is an inherited or secondary disorder caused by excessive iron storage leading to multiple organ damage. We describe 2 patients with diabetes mellitus caused by hemochromatosis secondary to multiple blood transfusions due to severe aplastic anemia. Subject 1, who was diagnosed with severe aplastic anemia at 15 years of age, received multiple red blood cell transfusions before he underwent autologous peripheral blood stem cell transplantation (PBSCT) at 22 years of age. At 21 years of age, hyperglycemia was detected with increased hemoglobin A1c and serum ferritin levels, 9.7% and 12,910 ng/mL (normal range, 20–320 ng/mL), respectively. The 24-hour urine C-peptide level was normal with negative antiglutamic acid decarboxylase antibody. Subsequently, metformin and an iron-chelating agent were administered. However, an intensive insulin regimen was necessary 2 years after the onset of diabetes. Subject 2, who was diagnosed with severe aplastic anemia at 2 years of age, received multiple blood transfusions until she underwent haploidentical PBSCT at 13 years of age. At 11 years of age, she developed diabetes mellitus with a high serum ferritin level (12,559.8 ng/mL). She is currently 18 years old and has been treated with an intensive insulin regimen and estrogen/progesterone replacement therapy because of hypogonadotropic hypogonadism. It is presumed that the loss of insulin secretory capacity and insulin resistance played a role in the pathogenesis of diabetes mellitus due to hemochromatosis in these cases.