X-linked sideroblastic anemia

Etiology: 1) defect in erythrocytic aminolevulinate synthetase 2) ineffective erythropoiesis 3) severity depends upon residual aminolevulinate synthetase activity Clinical manifestations: 1) refractory hemolytic anemia, pallor & weakness in infancy 2) hypersplenism 3) iron overload & hemosiderosis Laboratory: 1) complete blood count a) decreased hemoglobin b) decreased MCV c) decreased MCHC 2) peripheral blood smear a) microcytosis, hypochromic, anisocytosis, poikilocytosis, polychromasia b) leukocytes & platelets appear normal 3) urinalysis: porphyrins & their precursors within normal limits 4) feces: porphyrins & their precursors within normal limits 5) bone marrow biopsy a) hypercellular marrow with a left shift b) megaloblastic erythropoiesis with abnormal maturation c) sideroblast stained by Prussian-blue 6) genetic analysis: PCR Management: 1) anemia may respond to pyridoxine supplementation 2) supplemental folate might not be a bad idea 3) transfusion for patients unresponsive to pyridoxine 4) chelation therapy may be necessary for iron overload

General

sideroblastic anemia X-linked disease

References

Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 2157