Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Divalent metal transporter-1 (DMT1/DCT1/Nramp2) is the major Fe(2+) transporter mediating cellular iron uptake in mammals. Phenotypic analyses of animals with spontaneous mutations in DMT1 indicate that it functions at two distinct sites, transporting dietary iron across the apical membrane of intestinal absorptive cells, and transporting endosomal iron released from transferrin into the cytoplasm of erythroid precursors. DMT1 also acts as a proton-dependent transporter for other heavy metal ions including Mn(2+), Co(2+), and Cu(2), but not for Mg(2+) or Ca(2+). A unique mutation in DMT1, G185R, has occurred spontaneously on two occasions in microcytic (mk) mice and once in Belgrade (b) rats. This mutation severely impairs the iron transport capability of DMT1, leading to systemic iron deficiency and anemia. The repeated occurrence of the G185R mutation cannot readily be explained by hypermutability of the gene. Here we show that G185R mutant DMT1 exhibits a new, constitutive Ca(2+) permeability, suggesting a gain of function that contributes to remutation and the mk and b phenotypes.
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PMID:A spontaneous, recurrent mutation in divalent metal transporter-1 exposes a calcium entry pathway. 1502 13

A mutation of the iron transporter Nramp2 (DMT1, Slc11a2) causes microcytic anemia in mk mice and in Belgrade rats by impairing iron absorption in the duodenum and in erythroid cells, causing severe iron deficiency. Both mk and Belgrade animals display a glycine-to-arginine substitution at position 185 (G185R) in the fourth predicted transmembrane domain of Nramp2. To study the molecular basis for the loss of function of Nramp2(G185R), we established cell lines stably expressing extracellularly tagged versions of wild-type (WT) or mutated transporters. Like WT Nramp2, the G185R mutant was able to reach the plasmalemma and endosomal compartments, but with reduced efficiency. Instead, a large fraction of Nramp2(G185R) was detected in the endoplasmic reticulum, where it was unstable and was rapidly degraded by a proteasome-dependent mechanism. Moreover, the stability of the mutant protein that reached the plasma membrane was greatly reduced, further diminishing its surface density at steady state. Last, the specific metal transport activity of plasmalemmal Nramp2(G185R) was found to be significantly depressed, compared with its WT counterpart. Thus, a singlepoint mutation results in multiple biosynthetic and functional defects that combine to produce the impaired iron deficiency that results in microcytic anemia.
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PMID:Molecular and cellular mechanisms underlying iron transport deficiency in microcytic anemia. 1515 65

Hereditary sideroblastic anemia is a very rare disease recessive and X-linked that affect heme biosynthesis by deficit or decreased of delta aminolevulinic acid synthase (ALAS) activity. We report a case of a six-month-old boy, admitted in the hospital for anemic syndrome. The hemogram showed anemia (hemoglobin: 4.5 g/dL), frankly hypochronic microcytic and a regenerated (mean corpuscular hemoglobin concentration: 26 g/dL, mean cell volume: 53 fl, reticulocytes: 10 x 10(9)/L) with red cells morphologic disorders in smears (anisopoikylocytosis) without attack of the other lineages; white blood cells: 11 x 10(9)/L (neutrophils: 64% and lymphocytes: 35%); platelets: 350 x 10(9)/L. Examination of bone marrow showed an important erythroid hyperplasia (about 69%) with dyserythropoiesis. Perls stain revealed intense siderosis with 90% of ringed sideroblasts and a large number of siderocytes. Exploration of ALAS2 and ABC7 genes on the DNA of the infant was not found abnormalities. Treatment with pyridoxine corrects moderately the anemia. By the way, we proposed to remind that iron deficiency, inflammatory syndrome and thalassemia are the common microcytic anemia. However, it's mandatory to explore other causes if diagnosis is not solved.
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PMID:[Hereditary sideroblastic anemia: a rare diagnosis]. 1521 71

Classic iron deficiency (ID) does not represent a challenge for the laboratory and physicians. The anemia that accompanies infection, inflammation, and cancer, commonly termed anemia of chronic disease (ACD), features apparently normal or increased iron stores. However, 20% of these patients have iron-restricted erythropoiesis (functional ID), an imbalance between the iron requirements of the erythroid marrow and the actual iron supply. Functional ID leads to a reduction in red cell hemoglobiniza-tion, causing hypochromic microcytic anemia. The diagnosis of functional ID in real time is based on measuring the hemoglobin content of reticulocytes. An examination of the biochemical markers of iron metabolism demonstrates weaknesses in the diagnosis of functional ID. We developed a diagnostic plot for the assessment of iron status in ACD and the detection of advancing ID in patients with ID, ACD, and the combined state of functional ID and ACD. The plot indicates the correlation between a marker of the iron supply for erythropoiesis (ie, the ratio of the soluble transferrin receptor value to the logarithm of the ferritin value) and the reticulocyte hemoglobin content and functions as a marker of iron demand. The diagnostic plot shows good selectivity for assessing the iron status of disease-specific anemias such as classic ID, end-stage renal failure, cancer-related anemia, and the anemia of infection and inflammation. The therapeutic implications of the diagnostic plot are to differentiate patients who should be administered oral iron supplements, recombinant human erythropoietin (r-HuEPO), or a combination of r-HuEPO and iron. The response of erythropoiesis to r-HuEPO depends on the iron supply and the proliferation of erythropoiesis. The lack of an increase or a decrease in reticulocyte hemoglobin levels indicates a nonresponder to r-HuEPO or functional ID.
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PMID:Anemia of chronic disease: pathophysiology and laboratory diagnosis. 1579 May 48

In patients with renal failure, severe anemia and associated fatigue, cognitive and sexual dysfunctions have a significant impact on the quality of life. Anemia also represents an important etiological factor in the development of left ventricular hypertrophy. An inadequate production of a glycoprotein hormone, erythropoietin (EPO), is the major cause of anemia in presence of a reduction in the glomerular filtration rate. EPO is the primary regulator of the growth and survival of the erythroid progenitor. The treatment of anemia in chronic renal failure has been revolutionized by the introduction of recombinant human EPO. The vast majority of patients responds very well to treatment, although 5-10% of patients shows some resistance to EPO, the most common cause of which is iron deficiency. Several studies have recently been started in order to investigate the effects of preventing renal anemia from ever developing in uremic patients. The hemoglobin concentration target in pre-dialysis and dialysis patients is the subject of continuous re-assessment.
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PMID:Anemia and erythropoietin treatment in chronic kidney diseases. 1594 19

Sideroblastic anemia is an anemic condition characterized by chronic hypochromic anemia and the presence of large iron deposits in erythroid cells. Seven dogs with sideroblastic anemia were evaluated retrospectively. Historical, clinical, and clinicopathologic findings were reviewed to determine whether the condition was idiopathic or associated with disease conditions or drug or toxin exposure. Associated diseases were identified in 6 affected dogs and included acute hepatitis, pancreatitis, acute hepatitis and pancreatitis, inflammatory disease, glomerulonephritis, and myelofibrosis. None of the dogs had a history of recent exposure to drugs or toxins. One dog had no evidence of associated disease. Regardless of the associated disease condition, sideroblastic anemia was characterized by moderate to severe nonregenerative and frequently hypochromic anemia with prominent dysplastic features in bone marrow that were most prominent in the erythroid series. Survival varied from days to years. Identification of large numbers of siderocytes or sideroblasts in blood or bone marrow is inconsistent with a diagnosis of iron deficiency and should prompt a search for inflammatory disease conditions, including hepatitis, pancreatitis, and glomerulonephritis.
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PMID:Sideroblastic anemia in 7 dogs (1996-2002). 1595 46

Hypochromic, microcytic anemias are typically the result of inadequate hemoglobin production because of globin defects or iron deficiency. Here, we describe the phenotypic characteristics and pathogenesis of a new recessive, hypochromic, microcytic anemia mouse mutant, nm1054. Although the mutation nm1054 is pleiotropic, also resulting in sparse hair, male infertility, failure to thrive, and hydrocephaly, the anemia is the focus of this study. Hematologic analysis reveals a moderately severe, congenital, hypochromic, microcytic anemia, with an elevated red cell zinc protoporphyrin, consistent with functional erythroid iron deficiency. However, serum and tissue iron analyses show that nm1054 animals are not systemically iron deficient. From hematopoietic stem cell transplantation and iron uptake studies in nm1054 reticulocytes, we provide evidence that the nm1054 anemia is due to an intrinsic hematopoietic defect resulting in inefficient transferrin-dependent iron uptake by erythroid precursors. Linkage studies demonstrate that nm1054 maps to a genetic locus not previously implicated in microcytic anemia or iron phenotypes.
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PMID:nm1054: a spontaneous, recessive, hypochromic, microcytic anemia mutation in the mouse. 1599 89

The anaemia associated with chronic renal failure is multi-factorial. Although a relative erythropoietin deficiency is a major factor, it has also been recognized in recent times that uraemia is a chronic inflammatory state, and thus patients with renal failure also develop anaemia due to mechanisms associated with chronic inflammation. Thus, patients with chronic renal failure have activation of various immune cells, both monocytes and T-cells. These mononuclear cells have also been shown to release pro-inflammatory cytokines such as IL-1, IL-6, TNF-alfa and interferon gamma. These cytokines, particularly TNF-alfa and interferon gamma, are known to cause significant suppression of erythropoiesis. The exact molecular mechanism for this effect is not yet clear, but interferon gamma is an important stimulator of apoptosis in various cell types, including erythroid progenitor cells. This effect may be potentiated by other cytokines such as TNF-alfa, and this might then antagonise the anti-apoptotic action of erythropoietin on erythroid progenitors cells, thus reducing responsiveness to exogenous erythropoietic therapy. Chronic renal failure is also associated with increased hepcidin production which may also exacerbate the anaemia by inducing a functional iron deficiency in such patients.
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PMID:Hyporesponsiveness to erythropoietic therapy due to chronic inflammation. 1628 56

Iron has a fundamental role in many metabolic processes, including electron transport, deoxyribonucleotide synthesis, oxygen transport and many essential redox reactions involving haemoproteins and Fe-S cluster proteins. Defective iron homeostasis results in either iron deficiency or iron overload. Precise regulation of iron transport in mitochondria is essential for haem biosynthesis, haemoglobin production and Fe-S cluster protein assembly during red cell development. Here we describe a zebrafish mutant, frascati (frs), that shows profound hypochromic anaemia and erythroid maturation arrest owing to defects in mitochondrial iron uptake. Through positional cloning, we show that the gene mutated in the frs mutant is a member of the vertebrate mitochondrial solute carrier family (SLC25) that we call mitoferrin (mfrn). mfrn is highly expressed in fetal and adult haematopoietic tissues of zebrafish and mouse. Erythroblasts generated from murine embryonic stem cells null for Mfrn (also known as Slc25a37) show maturation arrest with severely impaired incorporation of 55Fe into haem. Disruption of the yeast mfrn orthologues, MRS3 and MRS4, causes defects in iron metabolism and mitochondrial Fe-S cluster biogenesis. Murine Mfrn rescues the defects in frs zebrafish, and zebrafish mfrn complements the yeast mutant, indicating that the function of the gene may be highly conserved. Our data show that mfrn functions as the principal mitochondrial iron importer essential for haem biosynthesis in vertebrate erythroblasts.
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PMID:Mitoferrin is essential for erythroid iron assimilation. 1651 96

The anemia of chronic kidney disease is associated with cardiovascular disease, decreased quality of life, and mortality. The introduction of recombinant human erythropoietin (rHuEPO) has transformed the management of this condition. However, a significant proportion of patients fail to respond to even high doses of rHuEPO. Several factors have been implicated in the hyporesponsiveness to rHuEPO. Iron deficiency, whether absolute or functional, is considered the most important, and maintenance of adequate iron stores reduces rHuEPO requirements among patients on hemodialysis. However, traditional indices of iron that are currently utilized may not reflect iron stores accurately, and there is also increasing concern regarding the potential long-term toxicity of parenteral iron therapy. Infection and inflammation also influence the response to rHuEPO, both by disruption of iron metabolism and by eliciting the release of cytokines that inhibit erythropoiesis. Oxidative stress may contribute to rHuEPO hyporesponsiveness directly by promoting lipid peroxidation in cell membranes, leading to increased erythrocyte fragility and reduced life span and also through its strong association with inflammation. Severe hyperparathyroidism can lead to a reduced number of erythroid progenitor cells. Inadequate dialysis dose, aluminum overload, nutritional factors such as deficiencies of carnitine, vitamin B12, folic acid, and vitamin C can also reduce the efficacy of rHuEPO therapy. Hyporesponsiveness to rHuEPO presents a challenge to both diagnosis and management in an era where optimizing response to rHuEPO is critical both in limiting the burgeoning costs of anemia management and improving clinical outcomes in the dialysis population.
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PMID:Managing erythropoietin hyporesponsiveness. 1655 Dec 93


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