Molecular defect in human erythropoietic protoporphyria with fatal liver failure

Nakahashi, Yoshitsugu; Mitsuya, Hiroaki; Kadota, Yoichi; Naitoh, Yasuyuki; Inoue, Katsumi; Yamamoto, Masayuki; Hayashi, Norio; Taketani, Shigeru

doi:10.1007/bf00217346

Cited by 47 publications

(13 citation statements)

References 13 publications

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“…The first case, reported by Nakahashi and co-workers (25), had a mutation at the donor site of intron 9 which resulted in the deletion of exon 9. Schneider-Yin et al reported a patient with a point mutation (175C→T) that caused a stop codon that produced a truncated protein (43).…”

Section: Discussionmentioning

confidence: 99%

“…Sarkany et al described two siblings that were compound heterozygotes for an exon 10 deletion and developed liver failure in adolescence (30); and proposed that recessive inheritance may be an important factor that predisposes patients with protoporphyria to develop liver disease. However, the patients reported by Nakahashi et al (25) and Schneider-Yin et al (43) both had autosomal dominant inheritance (44). Moreover, no patient in the present study had evidence for recessive inheritance.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies have begun to define the molecular causes of deficient FC activity in patients with protoporphyria (21,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32), and genetic heterogeneity has been found. The study reported here focused on identifying the FC gene defects in patients with protoporphyric liver disease who required liver transplantation, in order to determine if specific mutations were associated with this severe phenotype.…”

Section: Introductionmentioning

confidence: 99%

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Molecular defects in ferrochelatase in patients with protoporphyria requiring liver transplantation.

Bloomer¹,

Bruzzone²,

Zhu³

et al. 1998

J. Clin. Invest.

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Protoporphyria is a genetic disorder in which a deficiency of mitochondrial ferrochelatase activity causes accumulation of protoporphyrin that produces severe liver damage in some patients. In this study, mutations of the ferrochelatase gene were examined in eight unrelated patients who had liver transplantation. RNA was prepared from liver and/ or lymphoblasts, and specific reverse transcriptase-nested polymerase chain reactions amplified and sequenced ferrochelatase cDNAs. Products shorter than normal resulted from an exon 3 deletion in three patients, exon 10 deletion in two, exon 2 deletion in one, and deletion of five nucleotides in exon 5 in one. Sequence of normal-size products revealed no other mutations. Western blot showed a reduced quantity of normal-size ferrochelatase protein in protoporphyria liver compared with normal liver (19-51%, mean 32% of normal). Levels of the mitochondrial protein F 1 -ATPase ␤ -subunit were not decreased to a similar degree. Liver ferrochelatase activity was reduced more than could be explained by the decrease in ferrochelatase protein (4-20%, mean 9% of normal). These results establish genetic heterogeneity in the most severe phenotype of protoporphyria. However, the gene mutations found share the property of causing a major structural alteration in the ferrochelatase protein.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular defects in ferrochelatase in patients with protoporphyria requiring liver transplantation.

Bloomer¹,

Bruzzone²,

Zhu³

et al. 1998

J. Clin. Invest.

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“…A genetic defect in human ferrochelatase causes the disease erythropoietic protoporhyria. Exon deletions are common causes of this disease (32)(33)(34)(35)(36). A set of mutants containing individual deletions of exons 3 through 11 was previously constructed to study the underlying biochemical nature of erythropoietic protoporhyria (37).…”

Section: Characterization Of the C196s Mutant Of Humanmentioning

confidence: 99%

Evidence That the Fourth Ligand to the [2Fe-2S] Cluster in Animal Ferrochelatase Is a Cysteine

Sellers

Wang

Johnson

et al. 1998

Journal of Biological Chemistry

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The terminal enzyme in heme biosynthesis, ferrochelatase (E.C. 4.99.1.1), catalyzes the insertion of iron into protoporphyrin IX. Nuclear-encoded and produced in the cytoplasm, ferrochelatase is proteolytically processed upon translocation into the mitochondrion. In eukaryotes, the mature-length 42,000 Da protein is associated with the inner mitochondrial membrane, with the active site facing the mitochondrial matrix (1). The proposed catalytic mechanism (2) initially involves a metaldependent, enzyme-mediated distortion of the bound porphyrin ring allowing rapid insertion of Fe 2ϩ into the bent porphyrin (3). Distinct from the enzyme's catalytic activity, a labile 2ϩ cluster has been identified in several animal ferrochelatases including human (4), mouse (5), chicken, and frog (6). Although similar to the [2Fe-2S] 2ϩ centers found in plant ferredoxins, the ferrochelatase iron-sulfur cluster is more labile with enhanced sensitivity to degradation by nitric oxide (7). That the cluster plays no direct role part in catalysis is evidenced by the observation that bacterial, plant, and yeast ferrochelatases do not contain the metal center, and by studies showing that the redox state of the cluster is inconsequential to enzyme activity (4). However, when the cluster is disassembled, enzyme activity is lost (4, 7) and the protein readily precipitates. Hence the cluster appears to play a crucial role in maintaining protein structure in animal ferrochelatases and coupled with the sensitivity to nitric oxide, this has lead us to postulate that the cluster may serve as a regulatory NO 1 -sensor as part of an immune response (7).Site-directed mutagenesis of the five conserved cysteines closest to the COOH terminus of recombinant human ferrochelatase, identified Cys-403, Cys-406, and Cys-411 as ligands to the [2Fe-2S] cluster (8). Additionally, at this time it was proposed that certain spectroscopic anomalies and the unusual lability of the cluster may result from one noncysteinyl oxygenic ligand. The objective of the present investigation was to identify the fourth cluster ligand via additional mutagenesis experiments and by cloning, expression, and characterization of cluster-containing ferrochelatases from more distantly related organisms. We report here the first characterization of ferrochelatase from Drosophila melanogaster and, together with the new mutagenesis results with the human enzyme, these new data support the assignment of the cysteine located at position 196 in the human ferrochelatase as the fourth cluster ligand. Tracing the biological evolution of the ironsulfur cluster in ferrochelatase also provides further insight concerning the specific role of this metal center. EXPERIMENTAL PROCEDURESStrains and Cell Culture-Escherichia coli strain JM109 was used to express recombinant human ferrochelatase, mutant human ferrochelatase, and recombinant Drosophila ferrochelatase as described elsewhere (9). For the mutagenesis procedure described below, E. coli strain BMH mut-s was used to amplify the mutant plasmid. E...

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“…[7][8][9] Chronic liver disease is associated with marked PPIX accumulation in liver, which can begin insidiously. 10 The source of the excessive amounts of PPIX in patients with EPP is, according to most authors, the bone marrow, and mild anemia is observed in 20% to 50% of EPP patients. 11,12 Pathogenesis of the hematologic symptoms is not yet fully understood, and controversial hypotheses have been reported about its origin.…”

Section: Introductionmentioning

confidence: 99%

Increased plasma transferrin, altered body iron distribution, and microcytic hypochromic anemia in ferrochelatase-deficient mice

Lyoumi

Abitbol

Andrieu³

et al. 2006

Blood

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Patients with deficiency in ferrochelatase (FECH), the last enzyme of the heme biosynthetic pathway, experience a painful type of skin photosensitivity called erythropoietic protoporphyria (EPP), which is caused by the excessive production of protoporphyrin IX (PPIX) by erythrocytes. Controversial results have been reported regarding hematologic status and iron status of patients with EPP. We thoroughly explored these parameters in Fech m1Pas mutant mice of 3 different genetic backgrounds. FECH deficiency induced microcytic hypochromic anemia without ringed sideroblasts, little or no hemolysis, and no erythroid hyperplasia. Serum iron, ferritin, hepcidin mRNA, and Dcytb levels were normal. The homozygous Fech m1Pas mutant involved no tissue iron deficiency but showed a clear-cut redistribution of iron stores from peripheral tissues to the spleen, with a concomitant 2-to 3-fold increase in transferrin expression at the mRNA and the protein levels. Erythrocyte PPIX levels strongly correlated with serum transferrin levels. At all stages of differentiation in our study, transferrin receptor expression in bone marrow erythroid cells in Fech m1Pas was normal in mutant mice but not in patients with iron-deficiency anemia. Based on these observations, we suggest that oral iron therapy is not the therapy of choice for patients with EPP and that the PPIXliver transferrin pathway plays a role in the orchestration of iron distribution between peripheral iron stores, the spleen, and the bone marrow. IntroductionErythropoietic protoporphyria (EPP; Mendelian Inheritance in Man [MIM] 177000) is an inherited disorder caused by partial deficiency of ferrochelatase (FECH; EC 4.99.1.1.), the last enzyme of the heme biosynthetic pathway. 1 FECH is an inner membrane mitochondrial enzyme catalyzing the insertion of ferrous iron into protoporphyrin IX (PPIX) to form heme. FECH deficiency in bone marrow erythroid cells is responsible for the primary overproduction of PPIX, leading to an accumulation of protoporphyrin in the bone marrow, plasma, erythrocytes, skin, bile, and feces. 2 Because of its hydrophobic nature, PPIX can be removed from the body only through the liver, where it is secreted into bile and then is excreted by fecal elimination. 3 More than100 mutations in the FECH gene, including missense, nonsense, splicing, deletions, and insertions, have been identified in EPP families (Human Gene Mutation Database, http:// archive.uwcm.ac.uk/uwcm/mg/hgmd0.html). Usually, EPP is inherited as an autosomal pseudodominant disorder, and clinical penetrance is mainly modulated by the presence of a common intronic single-nucleotide polymorphism (SNP), IVS3-48C, in trans to a dominant mutation. 4,5 The most common clinical manifestation of EPP is lifelong acute photosensitivity of sun-exposed skin appearing in early childhood. 6 Although EPP is generally a benign disease, hepatic complications such as cholelithiasis or, in rare cases (approximately 2%), rapid fatal liver disease with cirrhosis may occur. [7][8][9] Chronic liver disease i...

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Molecular defect in human erythropoietic protoporphyria with fatal liver failure

Cited by 47 publications

References 13 publications

Molecular defects in ferrochelatase in patients with protoporphyria requiring liver transplantation.

Molecular defects in ferrochelatase in patients with protoporphyria requiring liver transplantation.

Evidence That the Fourth Ligand to the [2Fe-2S] Cluster in Animal Ferrochelatase Is a Cysteine

Increased plasma transferrin, altered body iron distribution, and microcytic hypochromic anemia in ferrochelatase-deficient mice

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