Severe refractory anemia with ringed sideroblasts and bone marrow aplasia in a child

Sideroblastic anemia is an extremely rare disorder in children. This report describes a 9-year 4-month-old girl with severe refractory anemia with ringed sideroblasts (RARS) that progressed to severe bone marrow aplasia. Ultrastructural studies revealed the presence of abundant intramitochondrial deposits of iron in erythroblasts similar to that observed in adults with this disorder. Although acid ferrocyanide staining confirmed the ferric valence of the iron deposits, they lacked morphologic and cytochemical characteristics associated with ferritin and hemosiderin. Bone marrow culture showed decreased or absent CFU-GEMM, CFU-GM, CFU-E, and BFU-E. Erythrocyte uroporphyrinogen I synthase, aminolevulinic acid dehydratase, uroporphyrinogen decarboxylase, urinary porphyrins, porphobilinogen, and aminolevulinic acid were normal. Free red cell protoporphyrin was increased. Therapy with corticosteroid and androgens was totally ineffective. The aplastic bone marrow in this child appeared to represent the end stage of RARS and differed from adults with RARS, who more frequently demonstrate a chronic course, often with the onset of leukemia as a terminal sequela. Although this case documents the occurrence of RARS in a child, additional reports of children with this disorder will be required to determine the prognosis and natural history of RARS in children.