Acquired or hereditary anemia marked by sideroblasts: bone marrow cells with large mitochondrial deposits of insoluble iron due to defective heme synthesis, leading to ineffective erythropoiesis.

Sideroblastic anemia, or sideroachrestic anemia, is a form of anemia in which the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes). In sideroblastic anemia, the body has iron available but cannot incorporate it into hemoglobin, which red blood cells need in order to transport oxygen efficiently...