X-linked sideroblastic anemia

X-linked sideroblastic anemia is not a porphyria but is included here because 6-aminolevulinic acid synthase is involved. 

Anderson KE et al Disorders of heme biosynthesis X-linked sideroblastic anemia and the porphyrias. In The Metabolic and Molecular Bases of Inherited Disease, 8th ed. Scriver CR et al (editors). McGraw-Hill, 2001. 

Cazzola M, May A, Bergamaschi G, Cerani P, FerriUo S, Bishop DF. Absent phenotypic expression of X-linked sideroblastic anemia in one of two brothers with a novel ALAS2 mutation. Blood 2002 100 4236-8. 

Defects in mitochondrial iron transport and utilization can result in mitochondrial iron overload. There is extensive iron accumulation in erythroblast mitochondria of both patients with X-linked sideroblastic anemia due to defective erythroid-speeifie 5-aminolevulinic acid synthase (eALAS) and those with ring sideroblasts associated with myelodysplastic syndrome. Mitochondrial iron overload has also been documented in patients with Friedreich s ataxia with defective frataxin" and in those with sideroblastic anemia with ataxia from defects in the Fe-S transporter ABC7. In addition, studies with yeast, the best studied eukaryotic model of Fe-S cluster synthesis, showed that defects in any of the enzymes of the Fe-S cluster assembly pathway caused mitochondrial iron accumulation and lack of normal mitochondrial function. ... 

The most common cause of iron overload is thalassemia, particularly in the parts of the world where it is prevalent (see earlier section). Indeed, the cardiac complications of iron overload are among the most common causes of death in I-thalassemia major. Sideroblastic anemias are a group of iron-loading disorders, many of which are of unknown cause. In a hereditary type of this disorder, there is deficiency of erythroid specific 5-aminolevulinic acid synthetase in RBC precursors because of mutations involving the X-linked gene that encodes this enzyme. Iron storage is common in patients with congenital dyserythropoietic anemia and may be found in patients with red cell enzyme deficiencies, particularly pyruvate kinase deficiency. ... 

Sideroblastic anemia j Aarskog-Scott syndrome PGK drficiency hemolytic anemia Charcot-Marie-Tooth disease Choroideremia Cleft palate, X-linked Spastic paraplegia, X-linked, 2 Deafness with stapes fixation 1 PRPS-related gout... 

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