ABSTRACT
Iron is an essential nutrient and a constituent of ferroproteins and enzymes crucial for human life. Generally, nonmenstruating individuals preserve iron very efficiently, losing less than 0.1% of their body iron content each day, an amount that is replaced through dietary iron absorption. Most of the iron is in the hemoglobin (Hb) of red blood cells (RBCs); thus, blood loss is the most common cause of acute iron depletion and anemia worldwide, and reduced hemoglobin synthesis and anemia are the most common consequences of low plasma iron concentrations. The term iron deficiency (ID) refers to the reduction of total body iron stores due to impaired nutrition, reduced absorption secondary to gastrointestinal conditions, increased blood loss, and increased needs as in pregnancy. Iron deficiency anemia (IDA) is defined as low Hb or hematocrit associated with microcytic and hypochromic erythrocytes and low RBC count due to iron deficiency. IDA most commonly affects women of reproductive age, the developing fetus, children, patients with chronic and inflammatory diseases, and the elderly. IDA is the most frequent hematological disorder in children, with an incidence in industrialized countries of 20.1% between 0 and 4 years of age and 5.9% between 5 and 14 years (39% and 48.1% in developing countries). The diagnosis, management, and treatment of patients with ID and IDA change depending on age and gender and during pregnancy. We herein summarize what is known about the diagnosis, treatment, and prevention of ID and IDA and formulate a specific set of recommendations on this topic.
ABSTRACT
Fibrogenesis is part of a normal protective response to tissue injury that can become irreversible and progressive, leading to fatal diseases. Senescent cells are a main driver of fibrotic diseases through their secretome, known as senescence-associated secretory phenotype (SASP). Here, we report that cellular senescence, and multiple types of fibrotic diseases in mice and humans are characterized by the accumulation of iron. We show that vascular and hemolytic injuries are efficient in triggering iron accumulation, which in turn can cause senescence and promote fibrosis. Notably, we find that senescent cells persistently accumulate iron, even when the surge of extracellular iron has subdued. Indeed, under normal conditions of extracellular iron, cells exposed to different types of senescence-inducing insults accumulate abundant ferritin-bound iron, mostly within lysosomes, and present high levels of labile iron, which fuels the generation of reactive oxygen species and the SASP. Finally, we demonstrate that detection of iron by magnetic resonance imaging might allow non-invasive assessment of fibrotic burden in the kidneys of mice and in patients with renal fibrosis. Our findings suggest that iron accumulation plays a central role in senescence and fibrosis, even when the initiating events may be independent of iron, and identify iron metabolism as a potential therapeutic target for senescence-associated diseases.
Subject(s)
Cellular Senescence , Senescence-Associated Secretory Phenotype , Humans , Iron , Kidney , FibrosisABSTRACT
BACKGROUND: Chronic diseases are associated with a range of functional and psychosocial consequences that can adversely affect patients' quality of life (QoL). Haemochromatosis (HC) is a genetically heterogeneous disorder characterized by chronic iron overload that can ultimately lead to multiple organ dysfunction. Clinical diagnosis remains challenging due to the nonspecificity of symptoms and a lack of confirmatory genotyping in a substantial proportion of patients. Illness perception among HC patients has not been extensively investigated, lacking relevant information on how to improve their QoL. METHODS: We present the results of the first worldwide survey conducted in nearly 1500 HC respondents, in which we collected essential demographic information and identified the aspects that concern HC patients the most. RESULTS: Out of all the participants, 45.3% (n = 676) voiced their concern about physical and psychological consequences such as HC-related arthropathies, which can ultimately affect their social functioning. A similar proportion of patients (n = 635, 42.5%) also consider that better-informed doctors are key for improved HC disease management. Taking a patient-centred approach, we expose differences in patients' disease perspective by social and economic influences. CONCLUSIONS: We identify potential targets to improve patients' health-related QoL and reflect on strategic measures to foster gender equity in access to health resources. Finally, we make a call for a highly coordinated effort across a range of public policy areas to empower participants in the HC research process and design. PATIENT OR PUBLIC CONTRIBUTION: Nearly 1500 patients with hereditary HC responded to an anonymized online survey in which research and clinical priorities were addressed regarding this chronic and rare disease.
Subject(s)
Hemochromatosis , Quality of Life , Humans , Quality of Life/psychology , Hemochromatosis/genetics , Hemochromatosis/therapy , Surveys and Questionnaires , ResearchABSTRACT
Congenital dyserythropoietic anemia type II (CDA II) is an inherited autosomal recessive blood disorder which belongs to the wide group of ineffective erythropoiesis conditions. It is characterized by mild to severe normocytic anemia, jaundice, and splenomegaly owing to the hemolytic component. This often leads to liver iron overload and gallstones. CDA II is caused by biallelic mutations in the SEC23B gene. In this study, we report 9 new CDA II cases and identify 16 pathogenic variants, 6 of which are novel. The newly reported variants in SEC23B include three missenses (p.Thr445Arg, p.Tyr579Cys, and p.Arg701His), one frameshift (p.Asp693GlyfsTer2), and two splicing variants (c.1512-2A>G, and the complex intronic variant c.1512-3delinsTT linked to c.1512-16_1512-7delACTCTGGAAT in the same allele). Computational analyses of the missense variants indicated a loss of key residue interactions within the beta sheet and the helical and gelsolin domains, respectively. Analysis of SEC23B protein levels done in patient-derived lymphoblastoid cell lines (LCLs) showed a significant decrease in SEC23B protein expression, in the absence of SEC23A compensation. Reduced SEC23B mRNA expression was only detected in two probands carrying nonsense and frameshift variants; the remaining patients showed either higher gene expression levels or no expression changes at all. The skipping of exons 13 and 14 in the newly reported complex variant c.1512-3delinsTT/c.1512-16_1512-7delACTCTGGAAT results in a shorter protein isoform, as assessed by RT-PCR followed by Sanger sequencing. In this work, we summarize a comprehensive spectrum of SEC23B variants, describe nine new CDA II cases accounting for six previously unreported variants, and discuss innovative therapeutic approaches for CDA II.
Subject(s)
Anemia, Dyserythropoietic, Congenital , Humans , Anemia, Dyserythropoietic, Congenital/genetics , Anemia, Dyserythropoietic, Congenital/metabolism , Mutation , Mutation, Missense , Exons , Alleles , Vesicular Transport Proteins/genetics , Vesicular Transport Proteins/metabolismABSTRACT
Divalent metal-iron transporter 1 (DMT1) is a mammalian iron transporter encoded by the SLC11A2 gene. DMT1 has a vital role in iron homeostasis by mediating iron uptake in the intestine and kidneys and by recovering iron from recycling endosomes after transferrin endocytosis. Mutations in SLC11A2 cause an ultra-rare hypochromic microcytic anemia with iron overload (AHMIO1), which has been described in eight patients so far. Here, we report two novel cases of this disease. The first proband is homozygous for a new SLC11A2 splicing variant (c.762 + 35A > G), becoming the first ever patient reported with a SLC11A2 splicing mutation in homozygosity. Splicing studies performed in this work confirm its pathogenicity. The second proband harbors the previously reported DMT1 G75R mutation in homozygosis. Functional studies with the G75R mutation in HuTu 80 cells demonstrate that this mutation results in improper DMT1 accumulation in lysosomes, which correlates with a significant decrease in DMT1 levels in patient-derived lymphoblast cell lines (LCLs). We also suggest that recombinant erythropoietin would be an adequate therapeutic approach for AHMIO1 patients as it improves their anemic state and may possibly contribute to mobilizing excessive hepatic iron.
Subject(s)
Anemia, Hypochromic , Anemia , Iron Overload , Anemia/genetics , Anemia, Hypochromic/genetics , Animals , Humans , Iron/metabolism , Iron Overload/metabolism , Mammals/metabolism , MutationABSTRACT
Hereditary hemochromatosis (HH) is an iron metabolism disease clinically characterized by excessive iron deposition in parenchymal organs such as liver, heart, pancreas, and joints. It is caused by mutations in at least five different genes. HFE hemochromatosis is the most common type of hemochromatosis, while non-HFE related hemochromatosis are rare cases. Here, we describe six new patients of non-HFE related HH from five different families. Two families (Family 1 and 2) have novel nonsense mutations in the HFE2 gene have novel nonsense mutations (p.Arg63Ter and Asp36ThrfsTer96). Three families have mutations in the TFR2 gene, one case has one previously unreported mutation (Family A-p.Asp680Tyr) and two cases have known pathogenic mutations (Family B and D-p.Trp781Ter and p.Gln672Ter respectively). Clinical, biochemical, and genetic data are discussed in all these cases. These rare cases of non-HFE related hereditary hemochromatosis highlight the importance of an earlier molecular diagnosis in a specialized center to prevent serious clinical complications.
Subject(s)
GPI-Linked Proteins/genetics , Hemochromatosis Protein/genetics , Hemochromatosis/genetics , Receptors, Transferrin/genetics , Adult , Codon, Nonsense/genetics , Female , GPI-Linked Proteins/metabolism , Hemochromatosis/physiopathology , Hemochromatosis Protein/metabolism , Histocompatibility Antigens Class I/metabolism , Humans , Iron/metabolism , Liver/metabolism , Male , Membrane Proteins/genetics , Middle Aged , Pedigree , Receptors, Transferrin/metabolismABSTRACT
Hereditary hyperferritinemia-cataract syndrome (HHCS) is a rare disease characterized by high serum ferritin levels, congenital bilateral cataracts, and the absence of tissue iron overload. This disorder is produced by mutations in the iron responsive element (IRE) located in the 5' untranslated regions (UTR) of the light ferritin (FTL) gene. A canonical IRE is a mRNA structure that interacts with the iron regulatory proteins (IRP1 and IRP2) to post-transcriptionally regulate the expression of proteins related to iron metabolism. Ferritin L and H are the proteins responsible for iron storage and intracellular distribution. Mutations in the FTL IRE abrogate the interaction of FTL mRNA with the IRPs, and de-repress the expression of FTL protein. Subsequently, there is an overproduction of ferritin that accumulates in serum (hyperferritinemia) and excess ferritin precipitates in the lens, producing cataracts. To illustrate this disease, we report two new families affected with hereditary hyperferritinemia-cataract syndrome with previous known mutations. In the diagnosis of congenital bilateral cataracts, HHCS should be taken into consideration and, therefore, it is important to test serum ferritin levels in patients with cataracts.
Subject(s)
Cataract/congenital , Ferritins/genetics , Iron Metabolism Disorders/congenital , Adult , Cataract/genetics , Child , Female , Humans , Iron/metabolism , Iron Metabolism Disorders/genetics , Iron-Regulatory Proteins/genetics , Mutation/geneticsABSTRACT
Supplemental Digital Content is available in the text.
ABSTRACT
Aceruloplasminemia is a rare autosomal recessive genetic disease characterized by mild microcytic anemia, diabetes, retinopathy, liver disease, and progressive neurological symptoms due to iron accumulation in pancreas, retina, liver, and brain. The disease is caused by mutations in the Ceruloplasmin (CP) gene that produce a strong reduction or absence of ceruloplasmin ferroxidase activity, leading to an impairment of iron metabolism. Most patients described so far are from Japan. Prompt diagnosis and therapy are crucial to prevent neurological complications since, once established, they are usually irreversible. Here, we describe the largest series of non-Japanese patients with aceruloplasminemia published so far, including 13 individuals from 11 families carrying 13 mutations in the CP gene (7 missense, 3 frameshifts, and 3 splicing mutations), 10 of which are novel. All missense mutations were studied by computational modeling. Clinical manifestations were heterogeneous, but anemia, often but not necessarily microcytic, was frequently the earliest one. This study confirms the clinical and genetic heterogeneity of aceruloplasminemia, a disease expected to be increasingly diagnosed in the Next-Generation Sequencing (NGS) era. Unexplained anemia with low transferrin saturation and high ferritin levels without inflammation should prompt the suspicion of aceruloplasminemia, which can be easily confirmed by low serum ceruloplasmin levels. Collaborative joint efforts are needed to better understand the pathophysiology of this potentially disabling disease.
Subject(s)
Ceruloplasmin/deficiency , Ceruloplasmin/genetics , Iron Metabolism Disorders/genetics , Neurodegenerative Diseases/genetics , Adult , Aged , Early Diagnosis , Female , Humans , Iron Metabolism Disorders/diagnosis , Iron Metabolism Disorders/pathology , Liver/pathology , Male , Middle Aged , Models, Molecular , Mutation , Neurodegenerative Diseases/diagnosis , Neurodegenerative Diseases/pathologyABSTRACT
Congenital Dyserythropoietic Anemia (CDA) is a heterogeneous group of hematological disorders characterized by chronic hyporegenerative anemia and distinct morphological abnormalities of erythroid precursors in the bone marrow. In many cases, a final diagnosis is not achieved due to different levels of awareness for the diagnosis of CDAs and lack of use of advanced diagnostic procedures. Researchers have identified five major types of CDA: types I, II, III, IV, and X-linked dyserythropoietic anemia and thrombocytopenia (XLDAT). Proper management in CDA is still unsatisfactory, as the different subtypes of CDA have different genetic causes and different but overlapping patterns of signs and symptoms. For this reason, we developed a new telemedicine tool that will help doctors to achieve a faster diagnostic for this disease. Using open access code, we have created a responsive webpage named CoDysAn (Congenital Dyserythropoietic Anemia) that includes practical information for CDA awareness and a step-by-step diagnostic tool based on a CDA algorithm. The site is currently available in four languages (Catalan, Spanish, Italian, and English). This telemedicine webpage is available at http://www.codysan.eu.
ABSTRACT
Ferritin is a multimeric protein composed of light (L-ferritin) and heavy (H-ferritin) subunits that binds and stores iron inside the cell. A variety of mutations have been reported in the L-ferritin subunit gene (FTL gene) that cause the following five diseases: (1) hereditary hyperferritinemia with cataract syndrome (HHCS), (2) neuroferritinopathy, a subtype of neurodegeneration with brain iron accumulation (NBIA), (3) benign hyperferritinemia, (4) L-ferritin deficiency with autosomal dominant inheritance, and (5) L-ferritin deficiency with autosomal recessive inheritance. Defects in the FTL gene lead to abnormally high levels of serum ferritin (hyperferritinemia) in HHCS and benign hyperferritinemia, while low levels (hypoferritinemia) are present in neuroferritinopathy and in autosomal dominant and recessive L-ferritin deficiency. Iron disturbances as well as neuromuscular and cognitive deficits are present in some, but not all, of these diseases. Here, we identified two novel FTL variants that cause dominant L-ferritin deficiency and HHCS (c.375+2T > A and 36_42delCAACAGT, respectively), and one previously reported variant (Met1Val) that causes dominant L-ferritin deficiency. Globally, genetic changes in the FTL gene are responsible for multiple phenotypes and an accurate diagnosis is useful for appropriate treatment. To help in this goal, we included a diagnostic algorithm for the detection of diseases caused by defects in FTL gene.
ABSTRACT
YARS2 variants have previously been described in patients with myopathy, lactic acidosis and sideroblastic anemia 2 (MLASA2). YARS2 encodes the mitochondrial tyrosyl-tRNA synthetase, which is responsible for conjugating tyrosine to its cognate mt-tRNA for mitochondrial protein synthesis. Here we describe 14 individuals from 11 families presenting with sideroblastic anemia and YARS2 variants that we identified using a sideroblastic anemia gene panel or exome sequencing. The phenotype of these patients ranged from MLASA to isolated congenital sideroblastic anemia. As in previous cases, inter- and intra-familial phenotypic variability was observed, however, this report includes the first cases with isolated sideroblastic anemia and patients with biallelic YARS2 variants that have no clinically ascertainable phenotype. We identified ten novel YARS2 variants and three previously reported variants. In vitro amino-acylation assays of five novel missense variants showed that three had less effect on the catalytic activity of YARS2 than the most commonly reported variant, p.(Phe52Leu), associated with MLASA2, which may explain the milder phenotypes in patients with these variants. However, the other two missense variants had a more severe effect on YARS2 catalytic efficiency. Several patients carried the common YARS2 c.572 G>T, p.(Gly191Val) variant (minor allele frequency =0.1259) in trans with a rare deleterious YARS2 variant. We have previously shown that the p.(Gly191Val) variant reduces YARS2 catalytic activity. Consequently, we suggest that biallelic YARS2 variants, including severe loss-of-function alleles in trans of the common p.(Gly191Val) variant, should be considered as a cause of isolated congenital sideroblastic anemia, as well as the MLASA syndromic phenotype.
Subject(s)
Acidosis, Lactic/genetics , Anemia, Sideroblastic/genetics , Genetic Diseases, X-Linked/genetics , Germ-Line Mutation , MELAS Syndrome/genetics , Mitochondrial Proteins/genetics , Tyrosine-tRNA Ligase/genetics , Acidosis, Lactic/enzymology , Adolescent , Anemia, Sideroblastic/enzymology , Female , Genetic Association Studies , Genetic Diseases, X-Linked/enzymology , Humans , Infant , MELAS Syndrome/enzymology , Male , Middle Aged , Mutation, Missense , Young AdultABSTRACT
Although guidelines are available for hereditary hemochromatosis, a high percentage of the recommendations within them are not shared between the different guidelines. Our main aim is to provide an objective, simple, brief, and practical set of recommendations about therapeutic aspects of HFE hemochromatosis for p.Cys282Tyr (C282Y/C282Y) homozygous genotype, based on the published scientific studies and guidelines, in a form that is reasonably comprehensible to patients and people without medical training. This final version was approved at the Hemochromatosis International meeting on 12th May 2017 in Los Angeles.
Subject(s)
Hemochromatosis , Female , Humans , Male , Chelation Therapy/methods , Diet , Hemochromatosis/genetics , Hemochromatosis/therapy , Hemochromatosis Protein/genetics , Homozygote , Phlebotomy/methodsABSTRACT
Hereditary hyperferritinaemia-cataract syndrome (HHCS) is a rare disorder usually caused by heterozygous mutations in the iron-responsive element (IRE) in the 5' untranslated region (5'UTR) of the L-ferritin gene (FTL), disturbing the binding of iron regulatory proteins (IRPs) and the post-transcriptional regulation of ferritin expression. Here, the proband of a consanguineous family displayed moderate bilateral cataracts and elevated serum ferritin in the absence of iron overload. The parents and siblings showed variable degrees of mild bilateral cataracts combined with elevated levels of circulating ferritin. Sequencing of FTL identified a novel 5'UTR mutation c.-151A > G, also named "Ghent +49A > G". The zygosity of the mutation, occurring in homozygous and heterozygous state in the proband and other affected family members respectively, correlated well with severity of ophthalmological and hematological manifestations. The substitution is expected to impair the secondary structure of the upper IRE stem. Functional characterization of +49A > G by electrophoretic mobility shift assays demonstrated a reduced binding affinity for IRP1 compared to the wild-type IRE of FTL. Overall, we have expanded the repertoire of deleterious biallelic FTL IRE mutations in HHCS with this novel +49A > G mutation, the zygosity of which correlated well with the disease expression.
Subject(s)
Apoferritins/genetics , Cataract/congenital , Iron Metabolism Disorders/congenital , Mutation , Adolescent , Adult , Cataract/genetics , Child , Female , Humans , Iron/metabolism , Iron Metabolism Disorders/genetics , Male , PedigreeABSTRACT
Cellular iron homeostasis is controlled by the iron regulatory proteins (IRPs) 1 and 2 that bind cis-regulatory iron-responsive elements (IRE) on target messenger RNAs (mRNA). We identified profilin 2 (Pfn2) mRNA, which encodes an actin-binding protein involved in endocytosis and neurotransmitter release, as a novel IRP-interacting transcript, and studied its role in iron metabolism. A combination of electrophoretic mobility shift assay experiments and bioinformatic analyses led to the identification of an atypical and conserved IRE in the 3' untranslated region of Pfn2 mRNA. Pfn2 mRNA levels were significantly reduced in duodenal samples from mice with intestinal IRP ablation, suggesting that IRPs exert a positive effect on Pfn2 mRNA expression in vivo. Overexpression of Pfn2 in HeLa and Hepa1-6 cells reduced their metabolically active iron pool. Importantly, Pfn2-deficient mice showed iron accumulation in discrete areas of the brain (olfactory bulb, hippocampus, and midbrain) and reduction of the hepatic iron store without anemia. Despite low liver iron levels, hepatic hepcidin expression remained high, likely because of compensatory activation of hepcidin by mild inflammation. Splenic ferroportin was increased probably to sustain hematopoiesis. Overall, our results indicate that Pfn2 expression is controlled by the IRPs in vivo and that Pfn2 contributes to maintaining iron homeostasis in cell lines and mice.