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Sideroblastic anemia (SBA)

Sideroblastic anemia (SBA) 

● Anemia in which the bone marrow produces ringed sideroblasts instead of healthy red blood cells (erythrocytes). 

● The human body has available iron, but it cannot be incorporated into hemoglobin, and red blood cells need to transport oxygen efficiently. 

Sideroblasts are atypical, nucleated red blood cells with abnormal nuclei, and iron particles accumulate in mitochondria around the nucleus. Sideroblasts are seen in aspirates of bone marrow. 

The ring Sideroblast is so named because the iron particles are arranged in a ring around the nucleus. 


1- Hereditary or congenital sideroblastic anemia could be X-linked or autosomal. ALA synthase deficiency. 

2. Acquired: 

a. Primary: Idiopathic. 

b. Secondary: 

- Toxins: lead or zinc poisoning. 

- Drugs: ethanol, isoniazid, chloramphenicol, 

cycloserine, Linezolid, oral contraceptives. 

- Nutritional: pyridoxine or copper deficiency. 

- Indirectly part of myelodysplastic syndrome. 

- Linked with Leukemia, Lymphoma, Rheumatoid arthritis, multiple myeloma. 


Pallor, fatiguability, dizziness, and hepatosplenomegaly. The accumulation of iron in these organs can lead to heart disease, liver damage, and kidney failure. 


1. appearance of Ringed sideroblasts in the bone marrow. 


2. The anemia is moderate to severe. 

3. Dimorphic with marked anisocytosis and poikilocytosis. marked Basophilic stippling, and common target cells. Pappenheimer bodies are present. 


4. MCV is decreased (i.e., microcytic anemia). 

5. RDW increases as the red blood cell histogram moves to the left. 

6. Leukocytes and platelets are normal. 

7. Bone marrow reveals erythroid hyperplasia with a maturation arrest. 

8. Over 40% of the developing erythrocytes are ringed sideroblasts. 

9. Increased Serum iron, percentage saturation, and serum ferritin. 

10. The TIBC is normal to decrease. 

11. Stainable marrow hemosiderin is increased. 

Laboratory findings: 

1. Increased ferritin levels. 

2. Normal total iron-binding capacity. 

3. The hematocrit of about 20-30%. 

4. Serum Iron: High. 

5. High transferrin saturation. 

6. MCV is usually normal or low. 

7. With lead poisoning, see RBC coarse basophilic stippling on peripheral blood smear 

8. Specific test: Prussian blue staining of red blood cells in the bone marrow. Shows ring sideroblasts. 

9. Can also cause microcytic hypochromic anemia. 


- Heart Failure, Pericarditis. 

- Formation of liver nodules & scar tissue 

- Diabetes mellitus. 

- Hypothyroidism, Secondary Hypopituitarism. 

- Skin darkening. 

- Leukemia. 
- sideroblastic anemia. 


1. Anemia is so severe that support with transfusion is required. 

2. Patients usually do not respond to erythropoietin therapy. 

3. In severe SBA cases, information on the success rate of bone marrow transplantation is limited. 

4. In the case of sideroblastic anemia caused by isoniazid, the addition of B6 is sufficient to correct the anemia. 

5. Deferoxamine is used to treat iron overload caused by blood transfusion. 

6. Bone marrow transplantation (BMT) is the last possible treatment.