Refractory anaemia with ring sideroblasts (RARS) is distinguished by hyperplastic inefficient erythropoiesis, aberrant mitochondrial ferritin accumulation and anaemia.
Early erythroblasts from patients with refractory anemia (RA) and RA with ringed sideroblasts (RARS) show constitutive mitochondrial release of cytochrome c. Moreover, mature erythroblasts in RARS, but not in RA, display aberrant accumulation of mitochondrial ferritin (MtF).