Congenital pure red cell aplasia, more commonly referred to as Diamond-Blackfan anemia, is a rare condition characterized by a selective depletion of erythroid precursors. The condition usually is detected in infants 2 weeks to 1 year of age. Laboratory findings include moderate to severe anemia, usually with no significant leukocyte or platelet abnormalities. Another classic finding is an absolute reticulocytopenia (decrease in the number of reticulocytes in the blood). A number of factors are believed to cause this disease but the most widely held theory is the presence of defective erythropoietic stem cells. Steroid therapy has become the standard treatment; transfusions and marrow transplants are used only in those individuals who do not respond to steroids.