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Sideroblastic anemia
Classification and external resources
ICD-10 D64.0-D64.3
ICD-9 285.0
OMIM 301310 206000 300751
DiseasesDB 12110
MeSH D000756

Sideroblastic anemia is caused by abnormal production of ringed sideroblasts,[1] caused either genetically or indirectly as part of myelodysplastic syndrome, [2] which can evolve into hematological malignancies (especially acute myelogenous leukemia). The body has iron available but cannot incorporate it into hemoglobin. Sideroblasts are seen in aspirates of bone marrow; these are atypical nucleated erythrocytes with granules of iron accumulated in perinuclear mitochondria.[3]

"Sideroachrestic anemia" is sometimes used as a synonym for sideroblastic anemia.

Contents

Classification

Sideroblastic anemia is typically divided into subtypes based on its cause.

  • Hereditary or congenital sideroblastic anemia may be X-linked[4] or autosomal.
OMIM Name Gene
300751 X-linked sideroblastic anemia (XLSA) ALAS2
301310 sideroblastic anemia with spinocerebellar ataxia (ASAT) ABCB7
205950 pyridoxine-refractory autosomal recessive sideroblastic anemia SLC25A38
206000 pyridoxine-responsive sideroblastic anemia  ?

GLRX5 has also been implicated.[5]

  • Acquired, or secondary, sideroblastic anemia develops after birth and is divided according to its cause.

Symptoms

Symptoms of sideroblastic anemia include skin paleness, fatigue, dizziness and enlarged spleen and liver. Heart disease, liver damage and kidney failure can result from iron buildup in these organs.[6]

Causes

The common feature of these causes is a failure to completely form heme molecules, whose biosynthesis takes place partly in the mitochondrion. This leads to deposits of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell. Sometimes the disorder represents a stage in evolution of a generalized bone marrow disorder that may ultimately terminate in acute leukemia.

Diagnosis

Ringed sideroblasts are seen in the bone marrow.

The anemia is moderate to severe and dimorphic with marked anisocytosis and poikilocytosis. Basophilic stippling is marked and target cells are common. Pappenheimer bodies are present. The MCV is decreased (i.e., a microcytic anemia). The RDW is increased with the red blood cell histogram shifted to the left. Leukocytes and platelets are normal. Bone marrow shows erythroid hyperplasia with a maturation arrest.

In excess of 40% of the developing erythrocytes are ringed sideroblasts. Serum iron, percentage saturation and ferritin are increased. The TIBC is normal to decreased. Stainable marrow hemosiderin is increased.

Laboratory findings

Treatment

Occasionally, the anemia is so severe that support with transfusion is required. These patients usually do not respond to erythropoietin therapy.[8] Some cases have been reported that the anemia is reversed or heme level is improved through use of moderate to high doses of pyrodoxine (Vitamin B6.) In severe cases of SBA, bone marrow transplant is also an option with limited information about the success rate. Some cases are listed on MedLine and various other medical sites. In the case of isoniazid-induced sideroblastic anemia, the addition of B6 is sufficient to correct the anemia.

See also

References

  1. ^ Caudill JS, Imran H, Porcher JC, Steensma DP (October 2008). "Congenital sideroblastic anemia associated with germline polymorphisms reducing expression of FECH". Haematologica 93 (10): 1582–4. doi:10.3324/haematol.12597. PMID 18698088. http://www.haematologica.org/cgi/pmidlookup?view=long&pmid=18698088.  
  2. ^ Sideroblastic Anemias: Anemias Caused by Deficient Erythropoiesis at Merck Manual of Diagnosis and Therapy Professional Edition
  3. ^ medical-dictionary
  4. ^ X-linked sideroblastic anemia at NLM Genetics Home Reference
  5. ^ Camaschella C (September 2008). "Recent advances in the understanding of inherited sideroblastic anaemia". Br. J. Haematol. 143 (1): 27–38. doi:10.1111/j.1365-2141.2008.07290.x. PMID 18637800. http://dx.doi.org/10.1111/j.1365-2141.2008.07290.x.  
  6. ^ Genetics Home Reference: Genetic Conditions > X-linked sideroblastic anemia Reviewed October 2006. Retrieved on 5 Mars, 2009
  7. ^ Aivado M, Gattermann N, Rong A, et al. (2006). "X-linked sideroblastic anemia associated with a novel ALAS2 mutation and unfortunate skewed X-chromosome inactivation patterns". Blood Cells Mol. Dis. 37 (1): 40–5. doi:10.1016/j.bcmd.2006.04.003. PMID 16735131. http://linkinghub.elsevier.com/retrieve/pii/S1079-9796(06)00089-1.  
  8. ^ Papadakis, Maxine A.; Tierney, Lawrence M.; McPhee, Stephen J. (2005). "Sideroblastic Anemia". Current Medical Diagnosis & Treatment, 2006. McGraw-Hill Medical. ISBN 0-07-145410-1.  

External links

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