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What is a sideroblast:
A nucleated red cell that has a stainable iron!

Sideroblastic Anemias:
Usually microcytic
Occasionally macrocytic
High iron/ferritin
Ineffective erythropoiesis
Mild hepatosplenomegaly (in hereditary SA, usually X-linked)

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Heterogenous group of disorders-characterized by presence of amorphous iron deposits in the form of ferric phosphate & ferric hydroxide in the erythroblast mitochondria.
Note that a ringed sideroblast is a nucleated red cell in which large prussian blue-positive granules form a full or partial ring around the nucleus.
Sideroblastic anemias are characterized y ineffective erythropiesis.
1. Erythroid hyperplasia in the bone marrow
2. Normal or slightly increased reticulocyte count
3. Hypochromic & microcytic erythorcytes
4. Often dimorphism is pronounced
5. The siderotic mitochondria of developing cells may be retained in some circulating red cells -pappenhemier bodies- which are pathognomonic siderocytes in the wright's stained blood smear.
6. Increased iron stores and erythropoietic hemochromatosis (more pronounced if patient does carry HFE mutations)

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CLASSIFICATION:

1. HEREDITARY (these do not evolve into leukemia)

-X-linked **most common**
...............erythroid-specific delta aminolevulinic acid synthase gene defect.
-Autosomal dominant
-Autosomal recessive
-Congenital (sporadic, pearson marrow-pancreas syndrome, DIDMOAD syndrome)

2. ACQUIRED
-PRIMARY (CLONAL)
MDS,
myeloproliferative disorders,
hematologic malignacies,
chemotherapy related

-REVERSIBLE
Alcoholism
Drugs (isoniazid, chloramphenicol)
Toxins (lead)
Copper deficiency - zinc overload
Hypothermia

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MANAGEMENT

1. Treat the underlying disease
2. Vitamin B6 trial 200 mg qd for two months. If it worked, then taper down to prevent the potential neurotoxicity
3. Transfusions, if necessary + Iron chelation
4. Folic acid (may or may not be helpful)
5. Bone marrow transplantation (i.e. MDS patients)
6. Family Survery