Autosomal recessive sideroblastic anemia

Autosomal recessive sideroblastic anemia is a rare inherited blood disorder characterized by the abnormal accumulation of iron in the mitochondria of developing red blood cells (erythroblasts) in the bone marrow, forming characteristic ring sideroblasts. This condition results from defects in mitochondrial heme biosynthesis or iron-sulfur cluster assembly, leading to ineffective erythropoiesis — the body's inability to produce functional red blood cells efficiently. Several genetic subtypes exist, including forms caused by mutations in genes such as SLC25A38 (the most common autosomal recessive form), GLRX5, and HSPA9, among others. Patients typically present with microcytic or normocytic anemia of variable severity, often manifesting in infancy or childhood with pallor, fatigue, and failure to thrive. Because the body continues to absorb excess iron despite ineffective red blood cell production, iron overload is a significant complication that can damage the liver, heart, and endocrine organs over time. Laboratory findings include low hemoglobin, elevated serum ferritin, increased transferrin saturation, and the presence of ring sideroblasts on bone marrow examination. Treatment depends on the severity of the anemia and the specific genetic subtype. Some patients respond to pyridoxine (vitamin B6) supplementation, particularly those with certain enzymatic deficiencies, though many autosomal recessive forms are pyridoxine-refractory. Red blood cell transfusions may be required for severe anemia, and iron chelation therapy is often necessary to manage or prevent iron overload. In severe cases, hematopoietic stem cell transplantation may be considered as a potentially curative option. Regular monitoring of iron status and organ function is essential for long-term management.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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